PT-141

What PT-141 is and how it works

PT-141 is bremelanotide, a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone. It is an agonist at melanocortin receptors, with high affinity for the melanocortin type 4 receptor and activity at the type 3 receptor as well. Both are expressed primarily in the central nervous system.^[1][10]

One molecule, three names. PT-141 is the development code, bremelanotide is the international nonproprietary name, and VYLEESI is the brand the molecule is approved and marketed under in the United States. The registers say so in their own schemas rather than by inference. PubChem, queried by name on 2026-09-01, resolves both bremelanotide and PT-141 to compound CID 9941379, whose synonym list holds PT-141, Bremelanotide [USAN:INN] and Vyleesi (TN) under CAS 189691-06-3, and whose molecular formula C50H68N14O10 at molecular weight 1025.2 is the formula and free-base weight the approved US labeling prints in its own DESCRIPTION section. ChEMBL's entry CHEMBL2070241, retrieved the same day, types each name in its own molecule_synonyms field — Bremelanotide | INN alongside PT-141 | RESEARCH_CODE — with max_phase 4.0 and first_approval 2019. And PubMed does not index the two names as two subjects: a search for PT-141 on 2026-09-01 is translated by the database itself into "bremelanotide"[Supplementary Concept] OR "bremelanotide"[All Fields] OR "pt 141"[All Fields], while bremelanotide NOT PT-141 on the same date returns 0 records against 121 for PT-141 alone and 109 for bremelanotide alone — every record indexed under the INN is also returned by a search on the development code. One caution about where each piece of that evidence comes from: the approved labeling never uses the string "PT-141", naming only the INN and the acetate salt. The label establishes the molecule; the name equivalence comes from the chemical and bibliographic registers.

The melanotan-II relationship, and its limit. A 2006 review of melanocortin peptide therapeutics describes PT-141 as an analog of melanotan II.^[5] That is a structural relationship and it is all it is. Melanotan II has its own page in this library, its own literature, and no approval anywhere; bremelanotide has a US approval, a label, and the trials summarized below, none of which studied melanotan II. Nothing transfers in either direction, and the two compounds sit in visibly different places in the federal record — a difference set out in the regulatory section below.

The central site of action is the point of difference. Phosphodiesterase type 5 inhibitors act on vascular smooth muscle in the periphery and address the plumbing of an erection; a melanocortin agonist acts on brain pathways involved in sexual response. In rats and nonhuman primates, systemic PT-141 produces erections, and it increases c-Fos immunoreactivity in hypothalamic neurons that occupy the same region as neurons labeled by pseudorabies virus injected into the corpus cavernosum. That is an anatomical argument that the drug is acting on a central circuit connected to the periphery.^[1]

PT-141 is unusual among the compounds in this library in one important respect: it is an approved drug. The FDA approved bremelanotide in 2019 under the brand name Vyleesi for premenopausal women with acquired, generalized hypoactive sexual desire disorder, and it is a self-administered, on-demand subcutaneous therapy rather than a daily one.^[10] Everything below is therefore a discussion of a regulated medicine with a label rather than a grey-market research compound, which raises the standard the evidence should be held to. The compound-level evidence grade on this page is human_rct because the page's typical claim — improvement in desire and desire-related distress in premenopausal women with HSDD — rests on two published randomized, placebo-controlled phase 3 trials; it is not a statement that every claim below is that well supported, and the mechanism claim below is graded animal-only and the durability claim anecdotal.

The compound's path to that approval was not direct. It was first developed as an intranasal treatment for male erectile dysfunction, tested in that form for several years, and only later redirected to subcutaneous administration in women with low desire.^[2][10]

What the research actually shows

The literature this page selects from is small, and its size is worth stating. PubMed record counts retrieved on 2026-09-01: bremelanotide returns 109 records, PT-141 returns 121, bremelanotide OR PT-141 returns 121, and bremelanotide AND randomized controlled trial[pt] returns 14. This is not a field where a page can pick a flattering subset without the omission being visible.

Two positive phase 3 trials in premenopausal women with HSDD. The RECONNECT programme comprised two identical randomized, double-blind, placebo-controlled, multicenter studies. Of 1,267 women randomized, 1,247 were in the safety population and 1,202 in the efficacy population; participants were mostly white, almost entirely at US sites, with a mean age of 39. Over 24 weeks of as-needed 1.75 mg subcutaneous dosing, both coprimary endpoints were met in both studies: desire, measured on the Female Sexual Function Index desire domain, improved by 0.30 and 0.42 over placebo, and distress related to low desire fell by 0.37 and 0.29.^[11]

The posted registry results agree with the publication — and add the number the publication leaves out. Both pivotal studies have results tables posted on ClinicalTrials.gov under NCT02333071 and NCT02338960; retrieved 2026-09-01, they reproduce the published between-group differences exactly. What they also print, which the abstract does not, is each arm on its own: the desire domain improved by 0.54 on drug against 0.24 on placebo in the first study and 0.63 against 0.21 in the second. Roughly a third of the improvement measured on the drug was also measured on placebo. That is a registry record rather than a published finding, and it is reported here as such.

The dose was chosen in a randomized dose-ranging trial before phase 3. A 12-week phase 2b study randomized premenopausal women with female sexual dysfunctions to placebo or to 0.75, 1.25 or 1.75 mg self-administered subcutaneously as desired, with 327 in the efficacy analysis. The pooled 1.25/1.75 mg comparison reported +0.7 versus +0.2 satisfying sexual events per month (p = 0.0180), +3.6 versus +1.9 on the Female Sexual Function Index total score (p = 0.0017), and −11.1 versus −6.8 on the desire/arousal/orgasm distress scale (p = 0.0014), with nausea, flushing and headache as the adverse events it names.^[7] The 1.75 mg amount the label carries is the top of a tested range, not an arbitrary one.

The blood-pressure effect was measured in its own randomized trial, not inferred from the safety database. A randomized, double-blind, placebo-controlled, parallel-arm study used ambulatory monitoring in 397 premenopausal women with normotension or controlled hypertension. In the 0-to-4 hour window after each of two doses given 24 hours apart, systolic pressure rose 2.4 and 3.0 mmHg over placebo at 1.25 mg (p = 0.029 and p = 0.076) and 3.1 and 3.2 mmHg at 1.75 mg (p = 0.006 and p = 0.027), with peaks typically lasting under 15 minutes; heart rate fell 4.6 to 4.7 beats per minute at 1.75 mg (p < 0.001). Both halves belong on the page: one of those four systolic comparisons did not reach significance, and although 26 participants discontinued for prespecified pressure increases, the proportions were similar across all four groups including placebo.^[8]

The safety picture across the whole programme is well characterized. Forty-three completed studies across phases 1 through 3 covered roughly 3,500 subjects, with phase 3 exposure up to 18 months. The dominant findings were tolerability effects: nausea in 40% versus 1.3% on placebo, flushing 20.3% versus 1.3%, headache 11.3% versus 1.9%, injection-site reactions 5.4% versus 0.5%. Focal hyperpigmentation was rare under labeled use but occurred in more than a third of subjects given up to 16 consecutive daily doses. Ambulatory monitoring showed small, transient, statistically significant blood-pressure increases.^[14]

A 52-week open-label extension reported no new safety signals. Of the 856 patients eligible after the controlled phase, 684 enrolled in the extension and 272 completed it. Improvements were maintained descriptively; the analysis was not controlled and was not intended to be.^[12]

The most recent pooled analysis is not hostile to the drug. A 2026 systematic review and meta-analysis of treatments for female sexual desire, arousal and orgasmic dysfunction, drawing on six databases plus the trial registry and carrying 36 studies through to abstraction, ran meta-analyses for mindfulness-based cognitive behavioural therapy, flibanserin and bremelanotide. It reported that bremelanotide improved the Female Sexual Function Index total score and both its desire and arousal subscales, and that all three modalities reduced distress; it also reported that no study directly compared psychological therapy with drug therapy.^[16]

The male erectile-dysfunction work is real but did not reach approval. Randomized, placebo-controlled intranasal studies in healthy men and in men with mild-to-moderate erectile dysfunction reported statistically significant erectile responses at doses above 7 mg, with onset around 30 minutes, and flushing and nausea as the commonest adverse events.^[2] A randomized crossover study found that adding a subtherapeutic intranasal dose to a low dose of sildenafil produced a greater erectile response than sildenafil alone.^[3] A larger randomized trial in sildenafil non-responders reported benefit as well, but that publication now carries a journal expression of concern, and this page does not treat it as support for anything.^[6]

Where the evidence is weak

The effect sizes are small, and independent analysts dispute what they mean. A change of 0.30 to 0.42 points on a desire-domain score is statistically reliable across 1,200 women and clinically modest. Two independent analyses go further. The first found that 72.72% of protocol-listed outcomes were not reported in the primary publication, that 15 reported secondary measures were absent from the protocols, and that no efficacy outcome was reported to CONSORT standards; its re-analysis from the FDA submission reproduced the published effect estimates but also surfaced an adverse-event-driven discontinuation odds ratio of 11.98 and a finding that participants substantially preferred placebo.^[13] The second examined the measurement properties of the instruments themselves and reported that the desire and distress scales have questionable validity evidence in women with HSDD, that previously unpublished protocol-specified outcomes showed effects ranging from nil to small, and that the categorical response outcomes had no validity evidence at all.^[15]

Placebo does most of the work in this therapeutic area generally. A 2018 meta-analysis of the placebo arms of randomized trials in female sexual dysfunction — a field-level analysis, not a bremelanotide trial, and it did not pool this compound — identified 24 randomized trials with a placebo arm, of which eight used the Female Sexual Function Index, covering 1,723 women on placebo against 2,236 on active treatment. It reported that 67.7% of the measured treatment effect across that literature was accounted for by placebo.^[9] That figure belongs to the field rather than to this molecule, and it is the reason the arm-level registry numbers above matter more than the between-group difference alone.

One randomized trial in an indication this page discusses has been retracted. A 2008 randomized, placebo-controlled, fixed-dose study of bremelanotide in female subjects with arousal disorder carries the PubMed publication type Retracted Publication, and PubMed's own title for it begins "RETRACTED:" (record PMID 18179455, checked 2026-09-01). A retracted paper is not evidence and is not cited on this page; it is named because the page discusses that indication and a reader searching it will find the paper. It is a different record from, and much larger than, the 18-subject arousal-disorder study cited below, which stands.

Author lists on the pivotal literature carry the sponsor's affiliation, and that is true consistently rather than selectively. Read from each record's own Affiliation field on PubMed on 2026-09-01: the two phase 3 publications, the open-label extension, the phase 2b dose-finding trial, the ambulatory blood-pressure trial and the programme-wide safety review each carry at least one author affiliation naming a company that developed or commercialized the drug. The two re-analyses, the approval summary, the 2018 placebo meta-analysis and the 2026 systematic review carry none. Sponsorship does not make a result wrong and the approval is not in question; it does mean the published effect sizes should be read as the most favorable defensible account, and the reporting problems above were identified by outside analysts working from the regulatory submission rather than from the published papers.

Nobody outside the approved population has been studied properly. There is no trial supporting use in postmenopausal women, in men with low desire, or in people without an HSDD diagnosis. The one non-retracted randomized study in premenopausal women looked at a different diagnosis, sexual arousal disorder. It enrolled 18 women, used a single intranasal dose, found no significant change in vaginal vasocongestion by photoplethysmography, reported subjective improvements only, and called itself preliminary.^[4]

Tolerability is the practical limit. Forty percent nausea is not a footnote, and it was the leading reason people stopped. The cumulative-dose hyperpigmentation finding means frequency of use matters in a way that is easy to ignore.^[14]

Long-term data stop at 18 months, in a self-selected group. No published study follows anyone beyond the extension phase, and the extension enrolled only people who had already tolerated the controlled phase.^[12]

Legal and regulatory status

Bremelanotide is FDA-approved, verified against openFDA on 2026-09-01. A query on the products.active_ingredients.name field for BREMELANOTIDE in the Drugs@FDA database returns exactly one application, NDA210557, whose product is VYLEESI (AUTOINJECTOR), a subcutaneous solution at EQ 1.75MG BASE/0.3ML, with marketing_status: Prescription and the sponsor of record printed as Cosette Pharmaceuticals; the original approval submission is dated 21 June 2019 and typed a new molecular entity. The same claim run on the openfda.generic_name field returns the same single application — the two row sets are identical, one application each and one in common. Enumerating the distinct ingredient strings in that result set returns exactly one value, and it is not the bare name: the register stores BREMELANOTIDE ACETATE, and on products.active_ingredients.name.exact the bare BREMELANOTIDE returns HTTP 404 while BREMELANOTIDE ACETATE returns the application, so the phrase field had matched the longer stored string. The development code finds nothing there: on 2026-09-01 both products.active_ingredients.name and openfda.generic_name queried for PT-141 returned HTTP 404 from Drugs@FDA, on the same two fields that returned the application for the INN.

Marketing status was checked rather than assumed. In the openFDA NDC directory on 2026-09-01, the finished product 0713-0897 carries a marketing_start_date of 12 November 2025 and no marketing_end_date. The current labeling is SPL set id f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dcf, version 1, effective 13 November 2025.

There is no boxed warning, and that was proved rather than assumed. Three checks on the openFDA drug-labeling endpoint on 2026-09-01. The base query on openfda.brand_name for VYLEESI returns HTTP 200 and one label, so the product is present in that corpus. The boxed_warning key is absent from that record's returned keys — checked by key presence, not by searching for a string. And openfda.brand_name:"VYLEESI" AND _exists_:boxed_warning returns HTTP 404, which on this API is an empty result rather than a missing route; the same-session positive control on the same field, openfda.generic_name:"estradiol" AND _exists_:boxed_warning, returns 426 labels against 489 for the unfiltered estradiol query, so the field is populated and the filter discriminates. What the label carries in sections rather than in a box is the contraindication in uncontrolled hypertension or known cardiovascular disease, and warnings on transient blood-pressure increase with heart-rate reduction, focal hyperpigmentation, and nausea.

The approval is narrow, and the labeling says so twice. The indication is the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder, characterized as low sexual desire causing marked distress or interpersonal difficulty and not due to a co-existing medical or psychiatric condition, problems with the relationship, or the effects of a medication or drug substance. The labeling then adds a Limitations of Use subsection: not indicated for the treatment of HSDD in postmenopausal women or in men, and not indicated to enhance sexual performance. The claim a reader arrives with — a libido peptide, for anybody, from any supply — is not the approved claim, and the label rules out two of its three parts in its own words. The labeling also advises effective contraception during treatment and stopping if pregnancy is suspected, on the basis of fetal harm in animal reproduction studies, with human pregnancy exposure in the trials too limited to determine risk. Its reported adverse-reaction discontinuation rate is 18% on drug against 2% on placebo, and its cap of no more than 8 doses a month has a published basis rather than an arbitrary one: focal hyperpigmentation appeared in more than a third of subjects given up to 16 consecutive daily doses.^[14]

Two federal records describe material that is not the approved product. The openFDA drug-enforcement database, queried on the product_description field on 2026-09-01, returns four Class II recall records for compounded preparations labeled with the development code, at strengths of 10 to 20 mg per millilitre against an approved 1.75 mg dose, every one for lack of assurance of sterility or associated manufacturing deviations; the same field queried for VYLEESI returns HTTP 404, and queried for bremelanotide returns two records, both already inside the set of four. The NDC directory on the generic_name field for bremelanotide on the same date returns ten rows, of which one is the approved finished prescription product and nine are bulk active-ingredient or further-processing registrations, four categorized BULK INGREDIENT FOR HUMAN PRESCRIPTION COMPOUNDING and two carrying the development code inside the registered name. Those are registry and enforcement facts about a category, stated because material labeled with this compound's name is not automatically the regulated product, and none of the published safety data above was generated with anything other than the regulated product.^[14]

Three FDA compounding documents, three dates, three negatives. All retrieved 2026-09-01. The 503A bulk drug substances list, self-dated Updated May 14, 2026, returns zero occurrences of bremelanotide, PT-141, PT 141 or melanotan, against an in-document positive control on Quinacrine Hydrochloride, which appears on 2 lines of that document. The separate 503B list, self-dated Updated March 21, 2025, returns zero for the same four terms against the same control term, which appears on 1 line of that document. FDA's separate page on bulk drug substances that may present significant safety risks, content current as of 04/22/2026, likewise returns zero for bremelanotide and for both spellings of the development code — but it does name Melanotan II, describing an immunogenicity risk for certain routes and citing published case reports of serious adverse events. Three documents, three different dates: a single date for "the FDA compounding lists" would be wrong, and the contrast between the two molecules is not small.

Anti-doping: not named, and structurally out of reach of the catch-all. Retrieved 2026-09-01 by way of the USADA prohibited-list page, which links the WADA-hosted assets. A text search of the 2026 WADA International Standard Prohibited List returned zero occurrences of bremelanotide, PT-141, PT 141, PT141, melanotan, melanocortin and Vyleesi, with in-document controls firing (testosterone on 32 lines, insulin on 5). The same seven terms returned zero in the 2026 Monitoring Program, whose own controls (ecdysterone, tramadol, caffeine) each fired once. Absence from the List is never a statement that a substance is permitted, and an athlete's position is a question for their own anti-doping authority. Section S0 is worth reading explicitly, because it is where an unapproved peptide would land: its trigger is conjunctive, covering a substance "not addressed by any of the subsequent sections of the List" and "with no current approval by any governmental regulatory health authority for human therapeutic use". The second condition fails on the current US approval verified above, so S0 cannot reach this compound however the first condition resolves. That is a materially different anti-doping position from an unapproved melanocortin peptide's, and it follows from the approval rather than from any finding about the drug.

Two labeled limits complete the picture, and both are descriptions of a regulated document rather than instructions from this page: no more than one dose in any 24 hours, which is the interval the ambulatory blood-pressure trial used between its two doses and measured across^[8], and a direction to stop after 8 weeks without symptom improvement. The label's own reason for the 24-hour limit is the risk of additive effects on blood pressure. One further distinction matters for anyone reading about "PT-141" rather than about Vyleesi: use in men and in postmenopausal women is off-label, and the male erectile-dysfunction programme was studied in a different formulation by a different route and never reached approval.^[2]

PHL does not sell peptides, does not prescribe, and takes no position on how any material reaches anyone.

Questions to bring to a provider

The approved indication is narrow and the diagnosis does real work, so the productive conversation starts there. Questions worth raising:

• Is low desire the actual problem, and is it acquired and generalized, or situational, or better explained by a relationship, a medication, sleep, mood, or a hormonal cause that should be worked up first?^[10]
• Given that the average trial benefit was a fraction of a point on a desire scale, and that the posted registry tables show the placebo arms improving too, what would a meaningful personal change look like, and how long would it be reasonable to try before calling it?^[11]
• Nausea affected four in ten participants and was the leading reason for stopping. What is the plan if that happens?^[14]
• Uncontrolled hypertension and known cardiovascular disease are labeled contraindications, and the product is not recommended for people at high cardiovascular risk. Where does the current blood-pressure and cardiac picture sit relative to that line, and does the ambulatory-monitoring finding change how it should be checked?^[8]
• The labeled frequency limit is no more than one dose in 24 hours and no more than 8 doses a month, and the labeling asks for roughly 45 minutes of lead time while saying the duration of effect is not characterized. What does that imply about how the drug would actually fit into a life, and what happens if that ceiling is not enough?^[10]
• The labeling advises effective contraception during treatment and stopping if pregnancy is suspected. Where does that sit against current plans?
• Are there interactions worth reviewing with current oral medications, particularly indomethacin or naltrexone?^[14]
• For anyone outside the approved population, meaning postmenopausal women and men, what is the actual evidence base, and what does off-label mean for monitoring and follow-up?^[4]
• If what is being considered is not the approved product but material carrying the same name, what is known about its identity and sterility, given the four Class II recall records above?

An approved drug with a modest, contested effect and a heavy tolerability burden is a reasonable thing to try and a reasonable thing to decline. Both are defensible; the point is to decide with the numbers in view.