Sexual health

Tadalafil

Name: Tadalafil: What the Research Actually Shows
Creator: Peptide Health Lab

Also known as: Cialis, Adcirca

Regulatory status: FDA approved
Evidence grade: Human RCT evidence

Last reviewed September 1, 2026 · 12 sources

What tadalafil is and how it works

Tadalafil is a small synthetic molecule — not a peptide — classified as a selective inhibitor of phosphodiesterase type 5. The approved US labeling describes the mechanism directly: sexual stimulation releases nitric oxide, which drives synthesis of cyclic GMP in smooth muscle; cyclic GMP relaxes that muscle and increases blood flow; PDE5 degrades cyclic GMP, and inhibiting PDE5 raises the amount available. The same labeling adds the sentence that makes this a conditional drug rather than an unconditional one — because sexual stimulation is required to initiate the local release of nitric oxide, inhibiting PDE5 has no effect in its absence. That is a regulatory document describing pharmacology and it is stated here without a citation for that reason.

Where the enzyme sits explains why one molecule has four approved indications. The labeling's clinical pharmacology section 12.1 names PDE5 in the smooth muscle of the corpus cavernosum, the prostate and the bladder as well as in vascular and visceral smooth muscle and elsewhere, and states that the effect on cyclic GMP seen in the corpus cavernosum and the pulmonary arteries is also observed in the prostate, the bladder and their vascular supply. It then says plainly that the mechanism for reducing prostate symptoms has not been established — a limit the label sets on itself, and one a randomized perfusion trial later failed to close.^[4]

Selectivity is where this molecule's own pharmacology is unusual, and it is not the retinal enzyme. The same section reports tadalafil as more than 10,000-fold more potent for PDE5 than for PDE1, PDE2, PDE3, PDE4 and PDE7, and 700-fold more potent than for PDE6, the retinal enzyme responsible for phototransduction. Its narrow ratios are against PDE11: 14-fold for PDE11A1 and 40-fold for PDE11A4, an enzyme the label locates in human prostate, testes and skeletal muscle. The labeling states that tadalafil inhibits recombinant PDE11A1, and to a lesser degree PDE11A4, at concentrations within the therapeutic range, and that the physiological role and clinical consequence of that inhibition in humans have not been defined. An unexplained inhibition inside the therapeutic range is a real open question, and it is specific to this molecule rather than to the class.

The retinal enzyme is on the label too, and its treatment there is worth carrying exactly rather than skipping. The same section attributes transient dose-related impairment of blue/green colour discrimination on the Farnsworth-Munsell 100-hue test to PDE6 inhibition as a class effect, records that across all clinical studies with the erectile-dysfunction product reports of changes in colour vision were rare, at under 0.1% of patients, and reports a dedicated study of a single 40 mg dose on vision (N=59) that found no effect on visual acuity, intraocular pressure or pupilometry. A 700-fold margin against PDE6, a rare-report frequency and a negative vision study are three separate statements, and dropping any one of them would misdescribe the label.

Two pharmacokinetic facts shape everything downstream. The labeled mean terminal half-life is 17.5 hours in healthy subjects, with a mean oral clearance of 2.5 L/hr — and in the separate pulmonary-hypertension labeling the same molecule is given 15 hours in healthy subjects and 35 hours in patients with pulmonary hypertension not receiving bosentan, so even within one molecule the number is scoped to a product and a population. And the rate and extent of absorption are stated as not influenced by food. Tadalafil is not sildenafil, not vardenafil and not avanafil; "PDE5 inhibitors" is a class, and a class-level result on this page is labelled as one every time it appears.

What the research actually shows

On the approved erectile-dysfunction claim, the randomized evidence is strong, large and old. An integrated analysis of six randomized, double-blind, placebo-controlled studies in 1,913 men with at least a three-month history of erectile dysfunction reported improvements on the erectile-function domain against placebo on both once-daily amounts, with 44.5% of men with severe baseline disease reaching the severity-specific clinically important difference on 5 mg against 11.6% on placebo. Its authors state the analysis is descriptive, and three of its five authors give a manufacturer as their affiliation.^[1]

Where the molecule is compared head to head, the direction runs against this page's subject and is stated anyway. A 2026 network meta-analysis of 83 double-blind placebo-controlled randomized trials in 6,029 participants, restricted to on-demand doses, ranked sildenafil 100 mg and 50 mg above tadalafil 20 mg and 10 mg on the odds of satisfactory erectile function, and concluded that sildenafil showed significantly greater efficacy compared with the other PDE5 inhibitors — while putting the odds of treatment-related adverse events lowest for tadalafil. Two of its twelve co-authors give a pharmaceutical company's medical-affairs departments as their affiliation, read from the record's own per-author affiliation entries rather than matched by surname; that is disclosed because the paper carries a comparative-efficacy claim.^[2]

On prostate symptoms the picture is thinner than the approval suggests. Against an alpha-blocker in 100 men over two months, tadalafil 5 mg once daily improved symptom score, flow rate and residual volume within its own arm, but the between-group differences were not significant and quality of life favoured the comparator.^[3] Added to an alpha-blocker across 11 trials and 940 patients, it improved symptom score, flow rate and erectile function — and raised the odds of pain more than fivefold and of other adverse events threefold.^[5] And the trial built to demonstrate the proposed mechanism did not: prostate transition-zone resistive index, the primary endpoint, MISSED at P = .118, with the perfusion secondary measures null alongside it.^[4]

In pulmonary arterial hypertension, the evidence is on a different product at a different dose. The 405-patient registration trial improved six-minute walk distance dose-dependently, but only the 40 mg once-daily arm met the prespecified level of significance, and the effect in patients already on bosentan had a confidence interval crossing zero.^[6] The one trial in this area with a hard composite clinical endpoint randomized 500 treatment-naive adults and put first clinical-failure events at 18% on ambrisentan plus tadalafil, 34% on ambrisentan alone and 28% on tadalafil 40 mg alone — the tadalafil monotherapy arm being the comparator that lost.^[7] A 2025 Cochrane review of nine trials in 1,807 participants is the counterweight: it grades the added benefit over a PDE5 inhibitor alone as very-low-certainty on clinical worsening and finds little to no difference in mortality.^[9] A fixed-dose macitentan-and-tadalafil single tablet outperformed tadalafil monotherapy on pulmonary vascular resistance, a haemodynamic surrogate, while its posted registry results record 3 deaths of 108 in the combination arm against 0 of 44 on tadalafil alone — and that is a finding about a different product, not about this ingredient.^[8]

Where the evidence is weak

The compound-level badge reads Human RCT evidence, and it is earned by the erectile-dysfunction and pulmonary-hypertension trials rather than by anything a wellness reader is asking about. That is the deliberate grading choice: the typical claim on this page — does it improve erectile function — rests on randomized placebo-controlled trials, so grading lower would contradict the evidence. Two claim areas are separately graded down to anecdotal because the evidence behind them is observational rather than randomized.

Every trial cited here enrolled people with a diagnosis, and most readers of this page do not have one. A PubMed search on 1 September 2026 for tadalafil AND "healthy volunteers"[mh] AND randomized controlled trial[pt] AND (libido OR "sexual desire") returned zero records, and a search for tadalafil AND randomized controlled trial[pt] AND "quality of life" AND healthy returned zero records. The distance between a man with a three-month history of erectile dysfunction in a manufacturer's trial and a person considering this as general sexual-wellness maintenance is the largest unmeasured gap on the page, and no count of trials closes it.

Most of the endpoints are surrogates. A resistive index is not a symptom, a pulmonary vascular resistance is not an outcome, and a six-minute walk distance is a proxy for capacity rather than a clinical event. Where a hard composite endpoint was measured, tadalafil monotherapy was the arm that performed worse than the combination.^[7] A PubMed search on 1 September 2026 for tadalafil AND randomized controlled trial[pt] AND (mortality OR "major adverse cardiovascular") returned 10 records, every one of them in a pulmonary-hypertension population — so for erectile dysfunction and prostate symptoms, the two indications most readers arrive for, no randomized clinical-event evidence surfaced by that search exists at all.

Two safety signals sit in tension with the labeling, and both halves belong here. The label's own conclusion is that neither the rare postmarketing reports nor the observational associations substantiate a causal relationship between PDE5 inhibitor use and non-arteritic anterior ischemic optic neuropathy; against it, a cohort study with a nested case-control analysis in 213,033 men reported an adjusted incidence rate ratio of 1.85 (95% CI 1.41-2.42) for a composite of three ocular outcomes — class-level rather than tadalafil-specific, and indexed by PubMed as a journal article rather than as a trial.^[10] On melanoma, a 2025 meta-analysis of 7,620,765 patients found a significant class-level odds ratio of 1.60 at 98% heterogeneity while the tadalafil-specific estimate, 1.54, was not significant (P = 0.203) — a shape that supports a scary sentence and a reassuring one equally well, which is why both figures are printed.^[12]

Industry authorship is present and disclosed on the same basis throughout. Affiliations were read from each record's own per-author affiliation entries rather than matched by surname, because surname matching sweeps in different people and PubMed reverses given and family order on some records. On that basis: the once-daily integrated analysis carries three manufacturer-affiliated authors of five; the perfusion trial carries a manufacturer-affiliated author; the 2026 network meta-analysis carries two industry-affiliated co-authors of twelve; and the fixed-dose combination trial is manufacturer-funded with three employee authors. No paper on this page is described as independent.

The counterfeit thread is real, documented, and it is about products that are not this drug. FDA's Health Fraud Product Database, retrieved from fda.gov on 1 September 2026 and parsed as a table of 2,197 data rows rather than searched as text, returns 283 rows naming tadalafil in the Subject column, spanning 2007 to 2026, split by action into 199 public notifications, 80 recalls, 3 warning letters and 1 safety alert. Counting the raw page text instead of the table returns 290, which is why the figure is a table parse and not a text search. Of those 283 rows, 262 name tadalafil itself and 21 name only a structurally modified analogue — aminotadalafil in 11, chloropretadalafil in 5, nortadalafil in 4 and N-desmethyl tadalafil in 1, which sums to the 21 exactly because no row in this set names more than one tadalafil analogue. The split is made by one rule, applied identically on this page and on the sildenafil page: a row counts as naming the ingredient itself only where the Subject cell carries the bare ingredient name as its own word, with no chemical modifier attached to it or standing immediately in front of it — so aminotadalafil reads as an analogue name, and so does the space-separated N-desmethyl tadalafil, and a row naming only an analogue class without naming a molecule would name no parent either, though no row in the tadalafil set takes that form. All of these are chemically distinct molecules and are not tadalafil. Separately, openFDA's drug enforcement endpoint returned 151 records on an unfielded full-text search for tadalafil on the same date, of which, classifying each by its own reason-for-recall text, 124 are undeclared-ingredient or unapproved-product findings and 27 are pharmaceutical-quality, compounding or labeling matters. The same endpoint on the fielded openfda.generic_name path returns only 9, because the undeclared-ingredient records are not annotated as approved drug products at all — which is the clearest available measure of what that thread is. These are findings about adulterated consumer products, not safety findings about the prescription molecule, and reading a Class I recall count as evidence about prescription-drug safety misreads the source.

Legal and regulatory status

Tadalafil is FDA-approved, on more than one application, for more than one indication, at more than one dose ceiling.

A Drugs@FDA query on the products.active_ingredients.name field for "TADALAFIL" on 1 September 2026 returned 52 applications covering 141 products. Running the same claim on openfda.generic_name returned 35, and the two row sets are nested — all 35 appear among the 52, 17 applications appear only in the larger set, none only in the smaller — so a two-field cross-check "agrees" here while silently omitting 17 applications. Enumerating the distinct ingredient names inside those 141 products gives TADALAFIL alone on 136, FINASTERIDE + TADALAFIL on 3 and MACITENTAN + TADALAFIL on 2: 48 applications carry at least one single-ingredient tadalafil product and 4 are combination-only. The .exact variant of the ingredient field returns the same 52, which is a fact about this molecule rather than a general property — the same filter on the same field for "ESTRADIOL" on the same date cuts 484 applications to 83, so the field discriminates and this census simply is not contaminated. A same-session negative control on that ingredient field for "ZZZNOTADRUGZZZ" returned HTTP 404, so a genuine empty set is distinguishable from a malformed query. Of the 141 products, 125 are in prescription marketing status and 16 are discontinued, none is over-the-counter, and the route is ORAL on all 141 — no parenteral tadalafil product exists in that register. Six applications are NDAs and 46 are ANDAs; one widely-named pulmonary-hypertension brand is an ANDA rather than an NDA, because famous names are not reliable guides to application type.

The indications are four, on two applications, and they are not interchangeable. The brand erectile-dysfunction labeling read for this page — application NDA 021368, SPL version 52, effective 3 June 2026, selected by sorting on effective time rather than on version number — carries three indication subsections: erectile dysfunction (1.1); the signs and symptoms of benign prostatic hyperplasia (1.2); and erectile dysfunction and the signs and symptoms of benign prostatic hyperplasia together (1.3). It then carries a fourth subsection that is a Limitation of Use (1.4): if the product is used with finasteride to initiate treatment for prostate symptoms, such use is recommended for up to 26 weeks, because the incremental benefit decreases from 4 weeks to 26 weeks and beyond 26 weeks is unknown. Separately, application NDA 022332, SPL version 34, effective 15 December 2025, is indicated for pulmonary arterial hypertension (WHO Group 1) to improve exercise ability, and states that the studies establishing effectiveness included predominantly patients with NYHA functional class II to III symptoms.

The labeled dosing is a regulatory fact and is described here rather than placed in the protocol block. The erectile-dysfunction label describes an as-needed regimen with a starting amount of 10 mg before anticipated activity, adjustable up or down, not to be taken more than once per day in most patients — and it makes an explicit post-dose efficacy claim, stating that the product was shown to improve erectile function compared to placebo up to 36 hours following dosing. It separately describes once-daily regimens across all three of its indications, taken without regard to timing of sexual activity for erectile dysfunction. The pulmonary-hypertension label's regimen is 40 mg (two 20 mg tablets) once daily, with the instruction that dividing that dose over the course of the day is not recommended. Both labels state the product may be taken without regard to food.

One badge covers all four indications, and the evidence beneath them is not comparable: randomized placebo-controlled trials pooling nearly two thousand men for erectile dysfunction,^[1] a 405-patient dose-ranging registration trial in which one arm carried the conclusion for pulmonary arterial hypertension,^[6] and, for prostate symptoms, a comparative result that was a null difference against an alpha-blocker in 100 men.^[3]

The absolute safety content, named by the section it comes from. On the erectile-dysfunction label, Contraindications section 4.1 makes any form of organic nitrate, regular or intermittent, a contraindication; section 4.3 does the same for guanylate cyclase stimulators such as riociguat, and section 4.2 for known serious hypersensitivity. Drug Interactions section 7.1 states that where nitrate administration is deemed medically necessary in a life-threatening situation, at least 48 hours should elapse after the last dose, under close medical supervision with hemodynamic monitoring — while the pulmonary-hypertension label states the same 48-hour interval inside its own Contraindications section 4.1 as a flat instruction rather than a supervised exception. Warnings sections 5.3, 5.4 and 5.5 cover prolonged erection and priapism, non-arteritic anterior ischemic optic neuropathy with the label's own non-causal hedge and its "crowded" optic disc note, and sudden decrease or loss of hearing with its own hedge. Section 2.7 splits the alpha-blocker instruction by indication: stable on the alpha-blocker first and start at the lowest recommended dose for erectile dysfunction, and not recommended in combination at all for prostate symptoms. Pediatric use is excluded on both applications, and section 8.4 additionally records a randomized, double-blind, placebo-controlled trial in children aged 7 to 14 with Duchenne muscular dystrophy, given 0.3 or 0.6 mg/kg daily for 48 weeks, which failed to demonstrate any benefit.

No single-ingredient tadalafil product carries boxed-warning text, and that was verified by inspecting field content rather than by reading a count. Querying openFDA's drug labeling endpoint on openfda.generic_name for "tadalafil" on 1 September 2026 returns 144 labels; adding an existence filter on the boxed_warning field returns 2. Both are artifacts. One is the macitentan-and-tadalafil fixed-dose combination under NDA 218490, whose 1,188-character boxed warning is an embryo-fetal toxicity warning belonging to the other ingredient, matched only because the generic-name phrase field is tokenized. The other, under ANDA 209907, has a boxed_warning field 13 characters long whose entire content is the literal string "BOXED WARNING" — a section heading with no warning text. A count-only sentence here would have been false. The same field query run on "estradiol" in the same session returned 426 labels carrying real warning text, so the field itself is functional.

Tadalafil is a prescription drug in the United States. It is not a controlled substance and it is not a dietary supplement. Prescription status, monitoring and any change in treatment are matters for the licensed prescriber managing the case.

In competitive sport, tadalafil is not named on the 2026 Prohibited List. Retrieved on 1 September 2026 through the United States Anti-Doping Agency's prohibited-list page to the WADA-hosted PDF of the World Anti-Doping Code International Standard Prohibited List 2026, which states that it comes into effect on 1 January 2026: case-insensitive searches of the extracted text for tadalafil, sildenafil, vardenafil, phosphodiesterase, PDE5 and PDE-5 each returned zero occurrences, while in-document positive controls on the same extracted text returned 32 for testosterone, 4 for erythropoietin and 2 for meldonium — so the zeros are real absences rather than a failed extraction. The same searches on the separately retrieved 2026 Monitoring Program returned zero, with its own in-document controls firing on tramadol, bupropion, caffeine, nicotine and ecdysterone. S0 Non-Approved Substances does not reach tadalafil, and that determination is stated rather than left to silence: S0 prohibits a substance that is both "not addressed by any of the subsequent sections of the List" and has "no current approval by any governmental regulatory health authority for human therapeutic use". The second condition fails on the verified US approvals described above — 125 products in prescription marketing status — so the conjunction is broken and S0 does not apply. Absence from the List is not a statement that a substance is permitted, and a tested athlete's question belongs with the relevant sport body before treatment begins, not after a test.

Questions to bring to a provider

Everything below turns on one prior question: which of the four approved indications, if any, the proposal is being made under — because the product, the dose and the population change with the answer.

Is any nitrate in use, in any form, regularly or intermittently, including one taken rarely for chest pain? This is an absolute labeled contraindication, and the labeling's 48-hour interval exists for life-threatening situations under monitoring rather than as a workaround.
Is a guanylate cyclase stimulator such as riociguat in use or under consideration, given that one of this molecule's own products treats the same condition riociguat does?
Is an alpha-blocker in use, and is the question being asked about erectile dysfunction or about prostate symptoms? The labeling gives different answers to those two questions, and the trial evidence for the combination reports more pain and more adverse events alongside the symptom benefit.^[5]
What is the cardiovascular assessment before anything is considered, given that the labeling frames sexual activity itself as carrying cardiac risk?
If prostate symptoms are the reason, what does it change to know that the labeling states the mechanism has not been established and that the randomized perfusion trial built to demonstrate it missed its primary endpoint?^[4]
If this is being considered without a diagnosis in any of the four approved indications, what evidence is the expectation resting on, and what population produced it?^[1]
Is there a history of non-arteritic anterior ischemic optic neuropathy, a "crowded" optic disc, or unexplained visual or hearing change?^[11]
Is there sickle cell anemia, multiple myeloma, leukemia or an anatomical deformation of the penis? The labeling names all four as conditions that might predispose to priapism, and it states that an erection lasting more than four hours is a reason to seek emergency medical attention.
Is there a personal or family melanoma history, given that the class-level association is significant and the molecule-level estimate is not?^[12]
What is the agreed review point, and what result would prompt stopping? The once-daily erectile-dysfunction evidence cited here runs 12 weeks, and the prostate-symptom comparison runs two months.^[3]

A clinician who wants the medication list before the conversation about efficacy is reading the same labeling this page describes.

Evidence by claim

Grades describe how strong the evidence is; the line under each grade describes what kind of studies it is. How we grade evidence.

Erectile function on a once-daily regimen

Human RCT evidence review

Established in randomized placebo-controlled trials, and this is the claim the compound-level badge rests on. An integrated analysis of six randomized, double-blind, placebo-controlled studies in 1,913 men reported least-squares mean improvements against placebo of 17.8% and 23.6% in Sexual Encounter Profile question 3 responses and of 4.2 and 5.4 points in the erectile-function domain on 2.5 mg and 5 mg once daily respectively (p<0.01), with severity-specific minimal clinically important difference reached by 44.5% of men with severe baseline erectile dysfunction on 5 mg against 11.6% on placebo. The analysis is indexed by PubMed as a journal article rather than as a randomized controlled trial, its authors state it can only provide descriptive results, and three of its five authors give a manufacturer as their affiliation. Every participant had at least a three-month history of erectile dysfunction; none was a man without the diagnosis.

[1]

Comparative efficacy against the other approved PDE5 inhibitors on demand

Human RCT evidence review

Evidence exists and it does not favour this molecule. A 2026 systematic review and network meta-analysis of 83 double-blind placebo-controlled randomized trials in 6,029 participants, restricted to on-demand doses, reported odds ratios against placebo for satisfactory erectile function of 9.06 for sildenafil 100 mg and 7.90 for sildenafil 50 mg, then 7.13 for tadalafil 20 mg and 3.14 for tadalafil 10 mg, and its stated conclusion is that sildenafil showed significantly greater efficacy compared with the other PDE5 inhibitors. The same analysis reported the odds of treatment-related adverse events as lowest for tadalafil, and noted that wide confidence intervals in some instances indicate uncertainty in the effect estimates. Two of its twelve co-authors give a pharmaceutical company's medical-affairs departments as their affiliation, read from the record's own author-affiliation entries rather than matched by surname; that disclosure is made because the paper carries a comparative-efficacy claim.

[2]

Lower urinary tract symptoms from benign prostatic hyperplasia, on tadalafil alone

Human RCT evidence human RCT

Randomized evidence exists and its comparative result is null. In 100 men with an International Prostate Symptom Score above 7, randomized to tadalafil 5 mg or tamsulosin 0.4 mg once daily for two months, symptom scores, peak flow rate and post-void residual improved within both groups but the between-group differences were not significant (P = .096, P = .552 and P = .131 respectively), and the quality-of-life index improved more in the alpha-blocker arm (P = .010). The authors conclude the two were equally efficacious in the majority of patients and call for larger trials. This is an open-label single-centre trial of 100 men, which is the ceiling of what this claim area rests on here.

[3]

The mechanism by which tadalafil relieves prostate symptoms

Human RCT evidence human RCT

Not established, and the strongest test of the leading hypothesis was negative. The approved labeling states in its own words that the mechanism for reducing benign-prostatic-hyperplasia symptoms has not been established. A randomized, double-blind, multicentre, placebo-controlled trial randomized 97 men aged 45 and over to tadalafil 5 mg once daily or placebo for 8 weeks with transrectal ultrasonography at baseline, 4 and 8 weeks; the primary efficacy measure, prostate transition-zone resistive index, MISSED — the overall treatment effect was not statistically significant (least-squares mean change: placebo -0.01, tadalafil 0.00, P = .118) — and colour pixel intensity and density were also null (P = .564 and P = .592). The authors' own reading is that detection may have been limited by low baseline resistive index or technique sensitivity, or that other mechanisms not assessed may be more prominently involved. A drug can relieve a symptom without the proposed mechanism being demonstrated, and that is what this claim area records.

[4]

Adding tadalafil to an alpha-blocker for prostate symptoms

Human RCT evidence review

Positive on symptom measures and negative on tolerability, and both halves are reported. A meta-analysis and meta-regression of 11 randomized controlled trials in 940 patients found combination therapy associated with greater reduction in overall symptom score (MD -2.78, 95% CI -3.97 to -1.59; P < 0.01), better erectile-function score (MD 2.98, 95% CI 1.64 to 4.33), better quality-of-life score, lower post-void residual and higher peak flow rate (MD 1.04, 95% CI 0.43 to 1.64) against tamsulosin alone — and a higher incidence of pain (OR 5.66, 95% CI 2.56 to 12.52) and of other adverse events (OR 2.97, 95% CI 1.60 to 5.49). Note the scope: this is an alpha-blocker taken alongside tadalafil in trials, which is not what the erectile-dysfunction label recommends for the prostate indication.

[5]

Exercise capacity in pulmonary arterial hypertension

Human RCT evidence human RCT

Established for one dose on one product in one population. The registration trial randomized 405 adults with pulmonary arterial hypertension to placebo or tadalafil 2.5, 10, 20 or 40 mg once daily for 16 weeks; six-minute walk distance increased dose-dependently but only the 40 mg arm met the prespecified level of significance (P<0.01), the overall placebo-corrected effect was 33 m (95% CI 15 to 50 m), and the effect was 44 m (95% CI 20 to 69 m) in bosentan-naive patients against 23 m (95% CI -2 to 48 m) — an interval crossing zero — in those on background bosentan. Time to clinical worsening improved on 40 mg (P=0.041) while the change in World Health Organization functional class was not statistically significant. The trial registration for this study records no posted results, checked on 1 September 2026. Nothing in this claim area transfers to erectile dysfunction: it is a different application, a different dose and a different population.

[6]

Clinical-event outcomes in pulmonary arterial hypertension

Human RCT evidence human RCT · review

This is the one claim area on the page whose PRIMARY endpoint was a composite clinical event rather than a surrogate, and it is a combination question. In an event-driven double-blind trial, 500 treatment-naive adults were randomized to ambrisentan 10 mg plus tadalafil 40 mg, to ambrisentan plus placebo, or to tadalafil 40 mg plus placebo, all once daily; a first clinical-failure event — death, hospitalization for worsening disease, disease progression, or unsatisfactory long-term clinical response — occurred in 18%, 34% and 28% of those groups, with a hazard ratio of 0.50 (95% CI 0.35 to 0.72; P<0.001) for combination against pooled monotherapy. The tadalafil monotherapy arm's 28% is the figure that belongs on this page, and it was the comparator that lost. A 2025 Cochrane review of nine trials in 1,807 participants separately grades the benefit of adding an endothelin receptor antagonist to a PDE5 inhibitor as very-low-certainty on clinical worsening and finds little to no difference in mortality, which is the counterweight.

[7] [9]

A fixed-dose macitentan and tadalafil combination product

Human RCT evidence human RCT

Cited here only to mark a boundary: a finding about a combination product is not a finding about tadalafil alone. The adaptive phase 3 trial randomized 187 patients to the single-tablet combination (n=108), to macitentan 10 mg (n=35) or to tadalafil 40 mg (n=44); pulmonary vascular resistance fell 28% more on the combination than on tadalafil (geometric mean ratio 0.72, 95% CL 0.64-0.80; P < 0.0001). The other half is material and the abstract states it: three patients died in the combination arm, and adverse events leading to discontinuation, serious adverse events and events of special interest were more frequent on the combination. The registry record for this trial carries posted results, checked on 1 September 2026, and they put deaths in the double-blind period at 3 of 108 on the combination against 0 of 44 on tadalafil monotherapy and 0 of 35 on macitentan monotherapy, and serious adverse events at 15 of 107 against 4 of 44 and 3 of 35. The endpoint here is a haemodynamic surrogate, not a clinical event.

[8]

Melanoma risk

Anecdotal reports only review

Graded down deliberately, because the evidence is observational and the two halves point in different directions. A 2025 systematic review and meta-analysis of eight studies in 7,620,765 patients reported a class-level association between PDE5 inhibitor use and melanoma (OR 1.60, 95% CI 1.13-2.27, P = 0.009) — at an I-squared of 98%, which the authors print — alongside a pooled hazard ratio of 1.10 (95% CI 1.03-1.17, P = 0.005, I-squared 43%). When the drugs were examined separately, the authors state that the increased incidence was not statistically significant for any of them, and the tadalafil-specific estimate was OR 1.54 (95% CI 0.79-3.00, P = 0.203, I-squared 96%). A class-level significant result whose molecule-level estimate is not significant is exactly the shape that gets misreported in both directions, so both figures are printed here.

[12]

Use by people without an approved indication

Anecdotal reports only review · human RCT

No randomized evidence located for this page addresses it. A PubMed search on 1 September 2026 for tadalafil AND "healthy volunteers"[mh] AND randomized controlled trial[pt] AND (libido OR "sexual desire") returned zero records, and a search for tadalafil AND randomized controlled trial[pt] AND "quality of life" AND healthy returned zero records. What the trials cited on this page did enrol is a positive fact about them and is the reason this entry carries the two citations it does: the once-daily erectile-dysfunction analysis enrolled 1,913 men with at least a three-month history of erectile dysfunction, and the pulmonary-hypertension registration trial enrolled 405 adults with idiopathic or associated pulmonary arterial hypertension, treatment-naive or on background bosentan. What that leaves for a reader with neither diagnosis is inference from a different population, which is what this grade records rather than a finding.

[1] [6]

Claim area	Evidence & sources	What the research shows
Erectile function on a once-daily regimen	Human RCT evidence review [1]	Established in randomized placebo-controlled trials, and this is the claim the compound-level badge rests on. An integrated analysis of six randomized, double-blind, placebo-controlled studies in 1,913 men reported least-squares mean improvements against placebo of 17.8% and 23.6% in Sexual Encounter Profile question 3 responses and of 4.2 and 5.4 points in the erectile-function domain on 2.5 mg and 5 mg once daily respectively (p<0.01), with severity-specific minimal clinically important difference reached by 44.5% of men with severe baseline erectile dysfunction on 5 mg against 11.6% on placebo. The analysis is indexed by PubMed as a journal article rather than as a randomized controlled trial, its authors state it can only provide descriptive results, and three of its five authors give a manufacturer as their affiliation. Every participant had at least a three-month history of erectile dysfunction; none was a man without the diagnosis.
Comparative efficacy against the other approved PDE5 inhibitors on demand	Human RCT evidence review [2]	Evidence exists and it does not favour this molecule. A 2026 systematic review and network meta-analysis of 83 double-blind placebo-controlled randomized trials in 6,029 participants, restricted to on-demand doses, reported odds ratios against placebo for satisfactory erectile function of 9.06 for sildenafil 100 mg and 7.90 for sildenafil 50 mg, then 7.13 for tadalafil 20 mg and 3.14 for tadalafil 10 mg, and its stated conclusion is that sildenafil showed significantly greater efficacy compared with the other PDE5 inhibitors. The same analysis reported the odds of treatment-related adverse events as lowest for tadalafil, and noted that wide confidence intervals in some instances indicate uncertainty in the effect estimates. Two of its twelve co-authors give a pharmaceutical company's medical-affairs departments as their affiliation, read from the record's own author-affiliation entries rather than matched by surname; that disclosure is made because the paper carries a comparative-efficacy claim.
Lower urinary tract symptoms from benign prostatic hyperplasia, on tadalafil alone	Human RCT evidence human RCT [3]	Randomized evidence exists and its comparative result is null. In 100 men with an International Prostate Symptom Score above 7, randomized to tadalafil 5 mg or tamsulosin 0.4 mg once daily for two months, symptom scores, peak flow rate and post-void residual improved within both groups but the between-group differences were not significant (P = .096, P = .552 and P = .131 respectively), and the quality-of-life index improved more in the alpha-blocker arm (P = .010). The authors conclude the two were equally efficacious in the majority of patients and call for larger trials. This is an open-label single-centre trial of 100 men, which is the ceiling of what this claim area rests on here.
The mechanism by which tadalafil relieves prostate symptoms	Human RCT evidence human RCT [4]	Not established, and the strongest test of the leading hypothesis was negative. The approved labeling states in its own words that the mechanism for reducing benign-prostatic-hyperplasia symptoms has not been established. A randomized, double-blind, multicentre, placebo-controlled trial randomized 97 men aged 45 and over to tadalafil 5 mg once daily or placebo for 8 weeks with transrectal ultrasonography at baseline, 4 and 8 weeks; the primary efficacy measure, prostate transition-zone resistive index, MISSED — the overall treatment effect was not statistically significant (least-squares mean change: placebo -0.01, tadalafil 0.00, P = .118) — and colour pixel intensity and density were also null (P = .564 and P = .592). The authors' own reading is that detection may have been limited by low baseline resistive index or technique sensitivity, or that other mechanisms not assessed may be more prominently involved. A drug can relieve a symptom without the proposed mechanism being demonstrated, and that is what this claim area records.
Adding tadalafil to an alpha-blocker for prostate symptoms	Human RCT evidence review [5]	Positive on symptom measures and negative on tolerability, and both halves are reported. A meta-analysis and meta-regression of 11 randomized controlled trials in 940 patients found combination therapy associated with greater reduction in overall symptom score (MD -2.78, 95% CI -3.97 to -1.59; P < 0.01), better erectile-function score (MD 2.98, 95% CI 1.64 to 4.33), better quality-of-life score, lower post-void residual and higher peak flow rate (MD 1.04, 95% CI 0.43 to 1.64) against tamsulosin alone — and a higher incidence of pain (OR 5.66, 95% CI 2.56 to 12.52) and of other adverse events (OR 2.97, 95% CI 1.60 to 5.49). Note the scope: this is an alpha-blocker taken alongside tadalafil in trials, which is not what the erectile-dysfunction label recommends for the prostate indication.
Exercise capacity in pulmonary arterial hypertension	Human RCT evidence human RCT [6]	Established for one dose on one product in one population. The registration trial randomized 405 adults with pulmonary arterial hypertension to placebo or tadalafil 2.5, 10, 20 or 40 mg once daily for 16 weeks; six-minute walk distance increased dose-dependently but only the 40 mg arm met the prespecified level of significance (P<0.01), the overall placebo-corrected effect was 33 m (95% CI 15 to 50 m), and the effect was 44 m (95% CI 20 to 69 m) in bosentan-naive patients against 23 m (95% CI -2 to 48 m) — an interval crossing zero — in those on background bosentan. Time to clinical worsening improved on 40 mg (P=0.041) while the change in World Health Organization functional class was not statistically significant. The trial registration for this study records no posted results, checked on 1 September 2026. Nothing in this claim area transfers to erectile dysfunction: it is a different application, a different dose and a different population.
Clinical-event outcomes in pulmonary arterial hypertension	Human RCT evidence human RCT · review [7] [9]	This is the one claim area on the page whose PRIMARY endpoint was a composite clinical event rather than a surrogate, and it is a combination question. In an event-driven double-blind trial, 500 treatment-naive adults were randomized to ambrisentan 10 mg plus tadalafil 40 mg, to ambrisentan plus placebo, or to tadalafil 40 mg plus placebo, all once daily; a first clinical-failure event — death, hospitalization for worsening disease, disease progression, or unsatisfactory long-term clinical response — occurred in 18%, 34% and 28% of those groups, with a hazard ratio of 0.50 (95% CI 0.35 to 0.72; P<0.001) for combination against pooled monotherapy. The tadalafil monotherapy arm's 28% is the figure that belongs on this page, and it was the comparator that lost. A 2025 Cochrane review of nine trials in 1,807 participants separately grades the benefit of adding an endothelin receptor antagonist to a PDE5 inhibitor as very-low-certainty on clinical worsening and finds little to no difference in mortality, which is the counterweight.
A fixed-dose macitentan and tadalafil combination product	Human RCT evidence human RCT [8]	Cited here only to mark a boundary: a finding about a combination product is not a finding about tadalafil alone. The adaptive phase 3 trial randomized 187 patients to the single-tablet combination (n=108), to macitentan 10 mg (n=35) or to tadalafil 40 mg (n=44); pulmonary vascular resistance fell 28% more on the combination than on tadalafil (geometric mean ratio 0.72, 95% CL 0.64-0.80; P < 0.0001). The other half is material and the abstract states it: three patients died in the combination arm, and adverse events leading to discontinuation, serious adverse events and events of special interest were more frequent on the combination. The registry record for this trial carries posted results, checked on 1 September 2026, and they put deaths in the double-blind period at 3 of 108 on the combination against 0 of 44 on tadalafil monotherapy and 0 of 35 on macitentan monotherapy, and serious adverse events at 15 of 107 against 4 of 44 and 3 of 35. The endpoint here is a haemodynamic surrogate, not a clinical event.
Melanoma risk	Anecdotal reports only review [12]	Graded down deliberately, because the evidence is observational and the two halves point in different directions. A 2025 systematic review and meta-analysis of eight studies in 7,620,765 patients reported a class-level association between PDE5 inhibitor use and melanoma (OR 1.60, 95% CI 1.13-2.27, P = 0.009) — at an I-squared of 98%, which the authors print — alongside a pooled hazard ratio of 1.10 (95% CI 1.03-1.17, P = 0.005, I-squared 43%). When the drugs were examined separately, the authors state that the increased incidence was not statistically significant for any of them, and the tadalafil-specific estimate was OR 1.54 (95% CI 0.79-3.00, P = 0.203, I-squared 96%). A class-level significant result whose molecule-level estimate is not significant is exactly the shape that gets misreported in both directions, so both figures are printed here.
Use by people without an approved indication	Anecdotal reports only review · human RCT [1] [6]	No randomized evidence located for this page addresses it. A PubMed search on 1 September 2026 for tadalafil AND "healthy volunteers"[mh] AND randomized controlled trial[pt] AND (libido OR "sexual desire") returned zero records, and a search for tadalafil AND randomized controlled trial[pt] AND "quality of life" AND healthy returned zero records. What the trials cited on this page did enrol is a positive fact about them and is the reason this entry carries the two citations it does: the once-daily erectile-dysfunction analysis enrolled 1,913 men with at least a three-month history of erectile dysfunction, and the pulmonary-hypertension registration trial enrolled 405 adults with idiopathic or associated pulmonary arterial hypertension, treatment-naive or on background bosentan. What that leaves for a reader with neither diagnosis is inference from a different population, which is what this grade records rather than a finding.

Typical protocol range in the research

An integrated analysis of six randomized, double-blind, placebo-controlled studies in 1,913 men with at least a three-month history of erectile dysfunction, treated once daily for 12 weeks. The figures below are the amounts the six trials administered by mouth in named arms

Tadalafil 2.5 mg once daily (394 men) or tadalafil 5 mg once daily (923 men), against once-daily placebo (596 men), for 12 weeks. Both amounts improved Sexual Encounter Profile question 3 responses and erectile-function domain scores against placebo (p<0.01); the analysis is descriptive and its authors say so [1]
An open-label randomized controlled trial in 100 men with benign prostatic hyperplasia and an International Prostate Symptom Score above 7, at a single tertiary teaching hospital, compared against an alpha-blocker rather than against placebo

Tadalafil 5 mg by mouth once daily for two months, against tamsulosin 0.4 mg by mouth once daily. Both arms improved within themselves; the between-group difference in symptom score was not significant (P = .096) and the quality-of-life index favoured the alpha-blocker arm (P = .010) [3]
The registration trial in pulmonary arterial hypertension: 405 adults with idiopathic or associated pulmonary arterial hypertension, either treatment-naive or on background bosentan, randomized double-blind for 16 weeks across four active dose arms and placebo

Tadalafil 2.5, 10, 20 or 40 mg by mouth once daily. Only the 40 mg arm met the prespecified level of statistical significance on the primary endpoint (P<0.01); the lower arms did not, so this is a dose-ranging range in which one arm carried the conclusion [6]

Every figure above is an amount administered to a named population in a named arm of a published trial, by mouth, with the indication and the regimen stated. A pulmonary-hypertension amount is never merged with an erectile-dysfunction one and an as-needed regimen is never merged with a once-daily one — they are different products at different dose ceilings. The as-needed erectile-dysfunction amounts that appear on the approved US labeling are a regulatory fact about a label and are described in the Legal and regulatory status section rather than lifted into a range here. A PubMed search on 1 September 2026 for tadalafil AND randomized controlled trial[pt] AND (mortality OR "major adverse cardiovascular") returned 10 records, every one of them in a pulmonary-hypertension population — none reports mortality or major adverse cardiovascular outcomes for tadalafil in an erectile-dysfunction or benign-prostatic-hyperplasia population, so no range on this page is backed by a clinical-event endpoint in the populations most readers of this page belong to.

Ranges are what published research reports, not a recommendation. PHL does not prescribe, and nothing here is personalized to you.

Side effects & safety signals

Non-arteritic anterior ischemic optic neuropathy and other ocular events

Reported rarely postmarketing, and the label's own causal language is hedged. Section 5.4 of the brand erectile-dysfunction label cites an observational case-crossover study with a class-level risk estimate of 2.15 (95% CI 1.06, 4.34) and a similar study at 2.27 (95% CI 0.99, 5.20), against a background annual incidence it states as 2.5 to 11.8 cases per 100,000 in males aged 50 and over · Both halves belong here. The label's own conclusion is that neither the rare postmarketing reports nor the association in the observational studies substantiate a causal relationship between PDE5 inhibitor use and this event, and that hedge is carried rather than dropped. Against it, a cohort study with a nested case-control analysis in 213,033 US men receiving PDE5 inhibitors reported an adjusted incidence rate ratio of 1.85 (95% CI 1.41-2.42) for a composite of serous retinal detachment, retinal vascular occlusion and ischemic optic neuropathy, and 2.02 (95% CI 1.14-3.58) for ischemic optic neuropathy alone. That study is class-level and observational, not tadalafil-specific and not randomized. A history of this event, or the "crowded" optic disc the labeling names, is a reason to raise this with a clinician before anything is considered.

[10]
Sudden decrease or loss of hearing

Reported postmarketing in temporal association with PDE5 inhibitors, including tadalafil, per section 5.5 of the brand erectile-dysfunction label, which gives no incidence figure. A 2019 systematic review of 22 articles found nine individual case reports, all male, mean age 57.4 years, of whom 25% had bilateral hearing loss and 22% had accompanying tinnitus · The labeling's own hedge is part of the fact: it states that these events may be accompanied by tinnitus and dizziness, that other medical conditions and factors were reported in some cases, that follow-up information was often limited, and that it is not possible to determine whether they are related directly to the drug. The systematic review lands in the same place from the other direction — all of its prospective studies failed to find a significant association, its retrospective results were heterogeneous, and its stated conclusion is that the literature is inconclusive. It is class-level rather than tadalafil-specific. The labeled instruction is to stop the drug and seek prompt medical attention if it happens.

[11]
Headache, myalgia and flushing

The most common treatment-related adverse events reported with tadalafil in the 405-patient pulmonary-arterial-hypertension registration trial, named as such by its authors · Framing rather than a verdict: these are the dose-related vasodilatory complaints that this drug class produces, and the registration trial describes tadalafil 40 mg once daily as well tolerated overall. The same profile recurs at the same dose in the 500-patient clinical-failure trial, where peripheral edema, headache, nasal congestion and anemia were more frequent on ambrisentan plus tadalafil than on either monotherapy — which is a statement about a combination arm, not about tadalafil alone.

[6] [7]
More frequent adverse events when tadalafil is added to an alpha-blocker for prostate symptoms

In a meta-analysis of 11 randomized controlled trials totalling 940 patients, adding tadalafil to tamsulosin raised the odds of pain (OR 5.66, 95% CI 2.56 to 12.52; P < 0.01) and of other adverse events (OR 2.97, 95% CI 1.60 to 5.49; P < 0.01) against tamsulosin alone · Reported alongside the benefit half from the same analysis, which found greater symptom-score, flow-rate and erectile-function improvement on the combination. The labeling treats this pairing differently depending on why it is being considered: section 2.7 of the brand erectile-dysfunction label says that for erectile dysfunction a patient should be stable on alpha-blocker therapy first and the PDE5 inhibitor started at the lowest recommended dose, while for benign prostatic hyperplasia it states that the product is not recommended for use in combination with alpha-blockers at all. Which question is being asked changes the labeled answer, which is a provider conversation rather than something a page can resolve.

[5]
Melanoma, as a class-level association that does not reproduce at molecule level

A 2025 systematic review and meta-analysis of eight studies in 7,620,765 patients reported a class-level odds ratio of 1.60 (95% CI 1.13-2.27, P = 0.009) at 98% heterogeneity, while the tadalafil-specific estimate was OR 1.54 (95% CI 0.79-3.00, P = 0.203, I-squared 96%) — not statistically significant · Both figures are printed because either one alone misdescribes the paper. The included studies are observational, the heterogeneity is extreme, and the authors' own separate-drug analysis reports that the increased incidence was not statistically significant for any individual agent. The paper's own closing advice is that people with a history of skin cancer, a family history of melanoma, or other risk factors should avoid these medications; that is the authors' recommendation, reported as theirs, and it is a provider-discussion flag rather than a verdict.

[12]
Comparative tolerability against the other approved PDE5 inhibitors

In a 2026 network meta-analysis of 83 double-blind placebo-controlled randomized trials in 6,029 participants restricted to on-demand doses, the odds of treatment-related adverse events against placebo were highest for vardenafil, then avanafil and sildenafil, and lowest for tadalafil · The favourable half of a paper whose efficacy conclusion runs the other way, and it is reported here for that reason. The same analysis states that wide confidence intervals in some instances indicate higher variability and potential uncertainty in the effect estimates, so the ranking is not a precise ordering. Two of its twelve co-authors give a pharmaceutical company's medical-affairs departments as their affiliation.

[2]

Published lists are never exhaustive, so report anything unexpected to a licensed provider.

Storage, handling & reconstitution

Lyophilized storage: Every one of the 141 products under the 52 Drugs@FDA applications returned on the products.active_ingredients.name field for "TADALAFIL" on 1 September 2026 is an oral product, none of them a lyophilized powder, and the finished dosage forms are tablets, an orally disintegrating tablet and an oral suspension. Storage is therefore whatever the dispensed container's labeling states rather than a research-peptide convention; the brand erectile-dysfunction labeling read for this page directs storage at 25 degrees Celsius (77 degrees Fahrenheit), with excursions permitted to 15 to 30 degrees Celsius (59 to 86 degrees Fahrenheit).
Reconstituted storage: Not applicable. Across the 141 products under the 52 applications the Drugs@FDA products.active_ingredients.name field returned for "TADALAFIL" on 1 September 2026, every dosage form is oral and none is a lyophilized powder, so there is no reconstituted storage window to describe and none is invented here. The oral suspension is supplied as a liquid, not as a powder a person mixes.
Reconstitution: Not applicable. Tadalafil is supplied only in oral dosage forms — tablets, an orally disintegrating tablet and an oral suspension. Every product row in the Drugs@FDA census read for this page carries the route ORAL, 141 of 141, and no parenteral tadalafil product exists in that register. There is no vial, no diluent and no powder, so there is nothing to reconstitute and no handling technique to describe.
Handling notes: The drug substance is described in the approved labeling as a crystalline solid that is practically insoluble in water, which is a description of the bulk chemical in a manufacturing context rather than of anything a person is dispensed. Nothing on this page describes the handling of unfinished material.

The how-to guides cover the conventions behind these fields, and what the published stability data does and does not establish: Storage, Reconstitution, Handling.

Working with a licensed provider

This is a prescription therapy. A licensed provider is required — to judge whether it is appropriate at all, to order and interpret the labs that monitor it, and to manage titration over time. Peptide Health Lab does not prescribe.

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Questions for your provider

Bring this page to a licensed provider. A provider can order labs, review your medications and history, and tell you whether anything here is relevant to your situation. This page can't. Peptide Health Lab does not prescribe and does not sell peptides.

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Citations

12 sources · every identifier checked against PubMed

[1] Tadalafil once daily in men with erectile dysfunction: an integrated analysis of data obtained from 1913 patients from six randomized, double-blind, placebo-controlled, clinical studies · European Urology, 2014. Review
[2] A comparative evaluation of on-demand phosphodiesterase-5 inhibitor efficacy in erectile dysfunction treatment: a systematic review and network meta-analysis of double-blind, placebo-controlled, randomized trials · The Journal of Sexual Medicine, 2026. Review
[3] Efficacy and safety of tadalafil vs tamsulosin in lower urinary tract symptoms (LUTS) as a result of benign prostate hyperplasia (BPH)-open label randomised controlled study · International Journal of Clinical Practice, 2020. Human RCT
[4] Effect of tadalafil once daily on prostate blood flow and perfusion in men with lower urinary tract symptoms secondary to benign prostatic hyperplasia: a randomized, double-blind, multicenter, placebo-controlled trial · Urology, 2014. Human RCT
[5] Tamsulosin plus Tadalafil compared with Tamsulosin alone for benign prostate hyperplasia in patients with or without erectile dysfunction: a meta-analysis and meta-regression of randomized controlled trials · World Journal of Urology, 2025. Review
[6] Tadalafil therapy for pulmonary arterial hypertension · Circulation, 2009. Human RCT
[7] Initial Use of Ambrisentan plus Tadalafil in Pulmonary Arterial Hypertension · The New England Journal of Medicine, 2015. Human RCT
[8] Randomized Trial of Macitentan/Tadalafil Single-Tablet Combination Therapy for Pulmonary Arterial Hypertension · Journal of the American College of Cardiology, 2024. Human RCT
[9] Phosphodiesterase type 5 inhibitor plus endothelin receptor antagonist compared to either alone for group 1 pulmonary arterial hypertension · Cochrane Database of Systematic Reviews, 2025. Review
[10] Risk of Ocular Adverse Events Associated With Use of Phosphodiesterase 5 Inhibitors in Men in the US · JAMA Ophthalmology, 2022. Human observational study
[11] Phosphodiesterase-5 (PDE-5) Inhibitors and Ototoxicity: A Systematic Review · Otology & Neurotology, 2019. Review
[12] Updated meta-analysis on the risk of melanoma associated with phosphodiesterase type 5 inhibitors · Melanoma Research, 2025. Review

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