Peptide Health Lab

Sexual health

PT-141

Also known as: Bremelanotide, Vyleesi

Regulatory status
FDA approved
Evidence grade
Human RCT evidence

Last reviewed August 2, 2026 · 11 sources

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][6]

That central location 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, defined as low sexual desire causing marked distress or interpersonal difficulty. It is a self-administered, on-demand subcutaneous therapy rather than a daily one.[6] Everything below is therefore a discussion of a regulated medicine with a label rather than a grey-market research compound. That changes what is known, and it raises the standard the evidence should be held to.

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][6]

What the research actually shows

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.[7]

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.[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.[10]

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.[5]

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.[9] 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.[11]

Trial sponsorship and reporting practice are part of the picture. The phase 3 programme was funded by the drug's developers, and the reporting problems above were identified by outside analysts working from the regulatory submission rather than from the published papers. That does not make the approval wrong. It does mean the published effect sizes should be read as the most favorable defensible account.

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 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.[10]

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.[8]

Legal and regulatory status

Bremelanotide is FDA-approved, the only compound in this batch that is. The approval, granted in 2019, covers premenopausal women with acquired, generalized hypoactive sexual desire disorder, and the product is dispensed as a self-administered on-demand subcutaneous autoinjector under the brand name Vyleesi.[6] It is a prescription medicine; a clinician makes the diagnosis, and the diagnosis is specific: acquired (previously present desire that declined) and generalized (not situational).

Being approved means the product carries a label, and the label carries limits that a research-compound framing tends to erase. It states a contraindication in uncontrolled hypertension or known cardiovascular disease, says the product is not recommended for people at high cardiovascular risk, caps frequency at one dose per 24 hours and no more than 8 doses per month, and directs stopping after 8 weeks without symptom improvement. Those are descriptions of a regulated document rather than instructions from this page, and they are the parts most often absent from discussion of "PT-141" as a peptide.[10]

Two distinctions matter for anyone reading about "PT-141" rather than about Vyleesi. First, use in men and in postmenopausal women is off-label: the male erectile-dysfunction programme was studied in a different formulation by a different route and never reached approval.[2] Second, material sold as "PT-141" outside the pharmacy channel is not the approved product, carries none of its labeling, release testing, or assigned expiry, and none of the safety data summarized above were generated with it.[10]

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?[6]
  • Given that the average trial benefit was a fraction of a point on a desire scale, what would a meaningful personal change look like, and how long would it be reasonable to try before calling it?[7]
  • Nausea affected four in ten participants and was the leading reason for stopping. What is the plan if that happens?[10]
  • 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?[10]
  • The labeled frequency limit is no more than one dose in 24 hours and no more than 8 doses a month. What does that imply about how the drug would actually fit into a life, and what happens if that ceiling is not enough?[6]
  • Are there interactions worth reviewing with current oral medications, particularly indomethacin or naltrexone?[10]
  • 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]

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.

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.

Sexual desire and desire-related distress in premenopausal women with HSDD
Human RCT evidence human RCT

Two identical 24-week phase 3 randomized, double-blind, placebo-controlled multicenter trials in 1,267 randomized women met both coprimary endpoints. Improvement in the Female Sexual Function Index desire domain was 0.30 and 0.42 over placebo in the two studies, and reduction in desire-related distress was −0.37 and −0.29. Statistically significant, consistent across two trials, and small in absolute terms.

[7]

Durability of benefit beyond 24 weeks
Anecdotal reports only human observational

A 52-week open-label extension reported sustained improvement and no new safety signals, but it was uncontrolled, analyzed descriptively, and enrolled only patients who had already tolerated the core phase. Of 856 eligible patients, 684 entered and 272 finished. Open-label continuation in a self-selected group is not evidence of durable efficacy.

[8]

Magnitude and validity of the measured benefit
Human RCT evidence review

Two independent analyses of the same trial data report that most protocol-specified efficacy outcomes went unpublished, that reported secondary measures were largely post hoc, and that the instruments used have limited validity evidence in this population. Re-analysis from the FDA submission reproduced the effect estimates but placed them alongside much higher adverse-event discontinuation and a participant preference for placebo. The benefit is real in the statistical sense and contested in the clinical sense.

[9] [11]

Erectile function in men
Human RCT evidence human RCT

Early randomized, placebo-controlled work with intranasal PT-141 reported dose-dependent erectile responses above 7 mg in healthy men and in men with mild-to-moderate erectile dysfunction, and a crossover study found that a subtherapeutic intranasal dose added to low-dose sildenafil produced a greater response than sildenafil alone. A larger randomized trial in sildenafil non-responders also reported benefit, but that publication now carries a journal expression of concern and should not be leaned on. No product is approved for men, and this line of development did not reach approval.

[2] [3] [5]

Central melanocortin mechanism
Animal studies only review

PT-141 is a synthetic analog of alpha-melanocyte-stimulating hormone and an agonist at the MC3 and MC4 receptors, which are expressed mainly in the central nervous system. In rats and nonhuman primates it produces erections, and systemic administration activates hypothalamic neurons that overlap anatomically with neurons connected to the penis by retrograde tracing. The mechanism is a central one, and it was worked out in animals.

[1] [6]

Use outside the approved population
Anecdotal reports only review · human RCT

The approval covers acquired, generalized hypoactive sexual desire disorder in premenopausal women. No trial supports use in postmenopausal women, in men with low desire, or as a general enhancer in people without a diagnosis. The one randomized study in premenopausal women with sexual arousal disorder, a different diagnosis, enrolled 18 subjects, used a single intranasal dose, found no change in the physiological measure of vaginal vasocongestion, and described itself as preliminary.

[6] [4]

Typical protocol range in the research

  • The two phase 3 RECONNECT trials, identical randomized, double-blind, placebo-controlled, multicenter studies in 1,267 premenopausal women with hypoactive sexual desire disorder, over 24 weeks of as-needed use

    1.75 mg subcutaneously, as needed before anticipated sexual activity [7]

  • The approved US labeling for the marketed product, an on-demand subcutaneous autoinjector rather than a titration schedule, as described in the approval summary and the programme-wide safety review

    A single self-administered 1.75 mg subcutaneous injection on demand; the safety review reports that focal hyperpigmentation was rare when the product was used in accordance with labeled recommendations and occurred in more than a third of subjects given up to 16 consecutive daily doses [6] [10]

  • Early intranasal studies in men with erectile dysfunction, a route and an indication that were never approved

    Intranasal doses above 7 mg produced a statistically significant erectile response versus placebo, with first erection at roughly 30 minutes; a maximum tolerated dose was not identified in those studies [2]

The approved product is an on-demand injection for one diagnosis in one population: acquired, generalized hypoactive sexual desire disorder in premenopausal women. The labeling puts two numerical limits on frequency and states both plainly: not more than one dose within any 24 hours, and more than 8 doses per month is not recommended. Describing those limits is describing the label, not advising anyone. The label attaches its own reasons to each: doses taken close together may have additive effects on blood pressure, and more frequent dosing raises the risk of focal hyperpigmentation and lengthens the part of the month when blood pressure is elevated. The label also directs discontinuation after 8 weeks if symptoms have not improved. Ranges here describe what the trials and the label report; the dispensed product's own labeling governs its use.

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

Side effects & safety signals

  • Nausea

    40.0% versus 1.3% on placebo in the integrated double-blind phase 3 data; 40.4% during the 52-week open-label extension · The most common adverse event and the most common reason participants stopped the drug. In the open-label extension, nausea was the only severe treatment-emergent event experienced by more than one participant in both studies. Mostly mild to moderate, but frequent enough to define the experience of using it.

    [10] [8]

  • Flushing, headache, and injection-site reactions

    Flushing 20.3% versus 1.3%, headache 11.3% versus 1.9%, injection-site reactions 5.4% versus 0.5%, drug versus placebo · Tolerability effects rather than safety signals, consistently reported across the phase 3 programme and its open-label extension, and consistent with the flushing and nausea seen in the earliest intranasal studies.

    [10] [7] [2]

  • Focal hyperpigmentation

    The approved labeling reports 1% of patients receiving up to 8 doses per month in the phase 3 trials versus none on placebo, and, from a separate clinical study, 38% after 8 consecutive daily doses with a further 14% developing new pigmentary changes over 8 more consecutive days. The programme-wide safety review describes it as rare under labeled dosing and as occurring in more than a third of subjects after up to 16 consecutive daily doses. · Darkening of the skin at discrete sites, tied to cumulative exposure and a predictable consequence of agonism at melanocortin receptors. The label names the face, gums, and breasts. Two qualifiers in the labeling are easy to miss and matter. Patients with dark skin were more likely to develop it, so the risk is not distributed evenly. And resolution after stopping was not confirmed in all patients, which means this is not reliably a temporary effect. The label directs prescribers to consider discontinuing if hyperpigmentation develops. This is the dose-frequency finding that most directly explains the labeled limits on how often the product may be used, and it is the effect most likely to be encountered by anyone using the compound outside the labeled pattern.

    [10]

  • Blood-pressure increases, plus a labeled contraindication in uncontrolled hypertension or known cardiovascular disease

    Small and transient but statistically significant on ambulatory monitoring across the development programme; the labeling describes maximal increases of about 6 mmHg systolic and 3 mmHg diastolic peaking 2 to 4 hours after a dose and returning to baseline usually within 12 hours · This is the one place on this page where the labeled position and the published review do not read the same way, and the difference is worth stating rather than smoothing over. The approved US labeling makes it a contraindication: the product is contraindicated in patients who have uncontrolled hypertension or known cardiovascular disease, is not recommended for patients at high risk for cardiovascular disease, and directs that cardiovascular risk be considered and blood pressure be well controlled before starting and periodically during treatment. The softer "should be used with caution in patients at risk of cardiovascular disease" wording, together with the judgement that the changes were not deemed clinically important, comes from the programme-wide safety review, a paper written by an author group that includes employees of AMAG Pharmaceuticals and Palatin Technologies, the companies that developed and marketed the drug. Where a sponsor-authored review and a label diverge, the label is the regulated statement. Existing hypertension or cardiovascular disease is not a caution here; it is a labeled contraindication, and it belongs in a clinician conversation before anything is considered.

    [10]

  • Drug interactions with orally administered medicines

    Documented for specific agents in the development programme · Most interaction studies found no clinically significant effect, with the exception of interactions that lowered plasma concentrations of indomethacin and naltrexone. Anyone taking regular oral medication has a concrete reason to have the list reviewed rather than assume no interaction.

    [10]

  • Adverse-event-driven discontinuation

    Odds ratio 11.98 (95% CI 3.74–38.37) for discontinuation due to adverse events versus placebo in an independent re-analysis · The same re-analysis reported that participants were substantially more likely to both complete the trial and enroll in the open-label extension if they had been on placebo (odds ratio 0.30). Whatever the average symptom score showed, the revealed preference of trial participants runs the other way, and that is a legitimate input to a decision.

    [9]

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

Storage, handling & reconstitution

Lyophilized storage
Bremelanotide is not supplied as a lyophilized powder. The approved product is a sterile solution already filled into a prefilled syringe inside a single-dose autoinjector, and the storage requirement is whatever the dispensed product's own labeling states: the labeling for the marketed autoinjector directs storage at or below 25 °C, protected from light, and not frozen. Because the dosage form is an approved, lot-released pharmaceutical, the storage answer comes from the carton it arrives in rather than from peptide convention.
Reconstitution
Not applicable. Bremelanotide is dispensed ready to use. The approved product is a single-dose, disposable prefilled autoinjector delivering 1.75 mg of bremelanotide in 0.3 mL of solution subcutaneously; the labeled procedure is to inspect the solution through the device's view window, remove the cap, and inject. There is no powder, no diluent, no vial-wall technique, and no unit math involved.
Handling notes
This is the one compound in this page group where a regulated product with a label, an assigned expiry, and lot-level release testing actually exists. Anything supplied outside that channel has none of those things, and every piece of published safety data below was generated with the regulated product.

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

Goal pages that include PT-141

Each one starts from the goal rather than the molecule, and grades what the evidence supports for that goal specifically.

  • Sexual health

    A research reference for the compounds mapped to sexual desire and sexual function, one of them FDA-approved with a labeled contraindication, one carrying the largest randomized literature in this library, and one whose approved use is local rather than systemic.

Questions for your provider

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Citations

11 sources · every identifier checked against PubMed

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