PT-141

01 · What it is

PT-141 is an FDA-approved drug whose pivotal trials, on independent re-analysis, produced no additional satisfying sexual events.

That sentence is not editorial. A 2021 review in Drug and Therapeutics Bulletin states it directly: in clinical trials, flibanserin led to an average of only one additional enjoyable sexual experience every two months, and bremelanotide to none ⁸.

What it is and where it stands. PT-141 is bremelanotide, marketed as Vyleesi, a melanocortin receptor agonist ¹⁴. It was approved by the FDA in 2019 for generalised acquired hypoactive sexual desire disorder in premenopausal women — one of two melanocortin peptide drugs approved that year, the other being afamelanotide, covered separately in this family ¹⁵. Its approval rests on RECONNECT: two identical phase 3, randomised, double-blind, placebo-controlled, multicentre trials ⁵, plus a 52-week open-label extension ⁶.

This is the most rigorously regulated compound in the project so far, and the independent critique of it is the sharpest. A 2021 re-analysis of the phase 3 trials found that none of the efficacy outcomes were reported in line with CONSORT standards, and that no secondary outcome had a stated rationale or cited evidence of validity — describing the observed benefits as modest, on incompletely reported post-hoc measures of questionable validity ⁷. A follow-up examined the measurement properties of the RECONNECT efficacy measures directly and is titled “Small Effects, Questionable Outcomes” ¹⁷.

And one bremelanotide trial has been retracted. A 2008 double-blind, placebo-controlled, fixed-dose randomised study in women with arousal disorder is flagged as retracted in the bibliographic record ¹.

PT-141 is approved, and approval is a regulatory fact rather than a measure of effect size. The rubric used here grades the state of the literature. For this compound the literature is unusually complete, unusually well controlled, and unusually contested about whether what it measured matters.

02 · Evidence at a glance

Evidence grade

Approved Pharma — FDA approval attested in the peer-reviewed literature ¹⁵

Generic and brand name

Bremelanotide; Vyleesi ¹⁴

Drug class

Melanocortin receptor agonist ¹⁴

Approval

FDA, 2019, for generalised acquired hypoactive sexual desire disorder in premenopausal women ^15,18

Pivotal evidence

RECONNECT — two identical phase 3 randomised, double-blind, placebo-controlled multicentre trials ⁵

Long-term data

52-week open-label extension; no new safety signals reported ⁶

Approved dose studied

1.75 mg subcutaneous ⁴

Independent re-analysis of phase 3

No efficacy outcome reported per CONSORT; no secondary outcome with stated rationale or evidence of validity ⁷

Effect on satisfying sexual events

None, per an independent review of the trial evidence ⁸

Measurement-properties critique

A dedicated 2024 analysis, “Small Effects, Questionable Outcomes” ¹⁷

Retracted trial in the record

Yes — a 2008 randomised study in female arousal disorder ¹

Safety profile

Adverse events mostly mild to moderate across phases 1–3 ¹⁰

Interaction study

Phase I with ethanol co-administration, including haemodynamic endpoints ²

Regulatory critique

A published argument that the approval reflects flawed regulatory precedent ⁸

03 · Mechanism of action

A melanocortin agonist acting centrally

Bremelanotide is a melanocortin receptor agonist hypothesised to trigger excitatory brain pathways in premenopausal women with hypoactive sexual desire disorder ¹⁴. That framing — hypothesised — is the reviewers’, and it is accurate: the compound is defined by its receptor class and its clinical effect, and the causal chain between them is proposed rather than demonstrated in the material cited here.

The wider melanocortin literature places it in context. The central melanocortin system is a target for metabolic disorders, and the 2019 approvals of bremelanotide and afamelanotide are cited as demonstrating the tractability of melanocortin receptors as drug targets ¹⁵.

What distinguishes PT-141 from the other melanocortin compounds in this family is receptor selectivity and route. It is a subcutaneous, on-demand drug at a defined dose ⁴, not a chronically dosed tanning agent — and the safety profile in Section 6 reflects that difference.

The mechanism is not what the argument is about

Unusually for this project, the dispute over PT-141 is not mechanistic. Nobody in the cited literature contests that the compound is a melanocortin agonist or that it does something. The argument is about measurement: whether the instruments used in the phase 3 trials capture something a person would recognise as benefit ^7,17.

That is a more advanced kind of disagreement than most compounds here reach, and it is only possible because the trials were done properly enough to be re-analysed.

04 · Key research findings

A retracted trial, 2008. A double-blind, placebo-controlled, fixed-dose randomised study of bremelanotide in female subjects with arousal disorder, flagged in the bibliographic record as retracted ¹.

The record does not state grounds in what was available here, so this guide states the fact and stops. It is the third retracted paper encountered in this project, and like the other two it was found by noticing a flag rather than by any systematic check.

Phase I with ethanol, 2017. A randomised, placebo-controlled, double-blind study of safety, tolerability, and haemodynamic and pharmacokinetic effects when co-administered with ethanol in healthy male and female participants ².

A deliberate interaction study with a substance the drug would realistically be taken alongside. Almost nothing else in this project has one.

Phase 2b responder analyses, 2019. Dose-ranging work whose responder definitions were then carried into the phase 3 registration studies at the 1.75 mg subcutaneous dose ⁴.

Defining responders in phase 2 and applying those definitions in phase 3 is orthodox drug development. It is also the step the later critiques scrutinise, because how a responder is defined determines what the pivotal trial can find.

RECONNECT, 2019 — the pivotal trials. Two identical phase 3, randomised, double-blind, placebo-controlled, multicentre studies evaluating safety and efficacy in premenopausal women with hypoactive sexual desire disorder ⁵.

The open-label extension, 2019. A 52-week extension of RECONNECT evaluating long-term safety and efficacy, reporting no new safety signals ⁶.

Fifty-two weeks of follow-up is more long-term human data than almost any compound in this project has.

The re-analysis, 2021. An independent re-analysis of the phase 3 trials finding that no efficacy outcome was reported in line with CONSORT data reporting standards, that no secondary outcome had a stated rationale or cited evidence of validity, and characterising the benefits as modest and resting on incompletely reported post-hoc measures of questionable validity ⁷.

This is the most substantial methodological critique of any trial programme in this project, and it was published in a peer-reviewed sexuality research journal rather than as commentary.

The regulatory critique, 2021. A review arguing that the approvals of bremelanotide and flibanserin represent a fallacy of regulatory precedent, noting that in clinical trials flibanserin produced an average of one additional enjoyable sexual experience every two months and bremelanotide none, and describing shifts in primary outcomes, a contested indication, and a politicised industry-sponsored advocacy campaign ⁸.

The zero is the number that matters, and it concerns the outcome closest to what a person would notice. This guide reports it as the reviewers’ characterisation of the trial evidence, not as a result computed here.

The safety programme, 2022. A review of the safety profile across phases 1 through 3, concluding that adverse events are mostly mild to moderate ¹⁰.

Prespecified and integrated subgroup analyses, 2022. Analyses across the RECONNECT programme ¹¹.

The measurement-properties analysis, 2024. An examination of the measurement properties of the efficacy measures used in the RECONNECT trials, framed around the principle that efficacy outcomes are informative only to the extent that they are validated ¹⁷.

Titled “Small Effects, Questionable Outcomes”. Together with the 2021 re-analysis ⁷, this is a sustained, specific, published argument that the pivotal trials measured the wrong things — and it comes from outside the sponsor.

Its arrival in the clinical literature, 2019. A concise drug-bulletin notice on Vyleesi for hypoactive sexual desire disorder appeared within weeks of approval, carrying no abstract in the indexed record ³.

Its place in current practice, 2022–2025. Reviews cover pharmacotherapy for sexual dysfunction in women ⁹, pharmacologic options across the field ¹³, and management where hypertension complicates the picture ¹². More recent ones position bremelanotide and flibanserin as the only FDA-approved medications for generalised acquired hypoactive sexual desire disorder in premenopausal women ¹⁸, cover clinical application alongside investigational alternatives ¹⁹, address specific populations such as women on endocrine therapy for breast cancer ²⁰, and include the drug among novel FDA-approved psychiatric medications of 2018–2022 ¹⁶.

The compound is in guidelines and in practice. Both things are true at once: it is an approved option clinicians use, and its evidence base is under sustained, credible methodological attack.

05 · Evidence overview

06 · Safety profile

Human data, and there is a proper amount of it. The safety profile has been reviewed across the full clinical development programme, phases 1 through 3, with adverse events characterised as mostly mild to moderate ¹⁰. The 52-week open-label extension reported no new safety signals ⁶. A phase I study specifically examined co-administration with ethanol, including haemodynamic and pharmacokinetic endpoints ².

This is what an actual regulatory safety dataset looks like, and it is worth stating plainly because almost nothing else in this project has one. The contrast with the melanocortin compounds that were never developed — covered elsewhere in this family — is the most useful thing a reader can take from this section.

What is genuinely unknown, or outside the studied population. Everything about use outside the approved population and route. The trial programme studied premenopausal women with a specific diagnosis, at a defined subcutaneous dose ^4,5. Nothing cited here establishes what the compound does in men, in postmenopausal women, at other doses, by other routes, or with repeated use beyond the studied schedule.

The safety review notes a finding it describes as not clinically important ¹⁰; the abstract text available here is truncated at that point, so this guide does not characterise what it was. That is logged rather than guessed.

Also unknown: the identity and purity of any material sold under this name outside a pharmacy supply chain. This gap matters more for an approved drug than for a research chemical, because a legitimate product exists against which unregulated material has no established relationship.

07 · US regulatory status

Current as of 7 September 2026. Bremelanotide was approved by the FDA in 2019 for generalised acquired hypoactive sexual desire disorder in premenopausal women, marketed as Vyleesi ^14,15,18. It is a prescription drug and is not a controlled substance.

This guide has not consulted the FDA approval record, label or review documents, and states the approval on the authority of the peer-reviewed sources cited ^15,18. Indication wording, contra- indications and warnings are matters for the label, which is not reproduced or paraphrased here.

Material sold under the name PT-141 outside a pharmacy is not the approved product and has no established relationship to it.

Under the World Anti-Doping Code, bremelanotide does not appear as a named prohibited substance in the classes reviewed for this guide. Competitors should consult the current Prohibited List directly rather than rely on secondary summaries, including this one.

08 · Limitations of the evidence

1. Independent re-analysis found the pivotal trials’ outcome reporting deficient. No efficacy outcome reported in line with CONSORT; no secondary outcome with a stated rationale or cited evidence of validity; benefits characterised as modest and resting on incompletely reported post-hoc measures of questionable validity ⁷. A second analysis examined the measurement properties directly and reached a similar conclusion ¹⁷.
2. On the outcome closest to lived experience, the reported effect is zero. An independent review states that in clinical trials bremelanotide produced no additional enjoyable sexual experiences ⁸. Statistical significance on a desire or distress scale and zero additional events are compatible findings, and that compatibility is the whole argument.
3. Approval is not an effect size. FDA approval ¹⁵ establishes that a regulator was satisfied on its own criteria. The published critique argues those criteria were met through shifts in primary outcomes and a contested indication, in a context including industry-sponsored advocacy ⁸. This guide reports the critique as a published argument, not as an established finding.
4. A trial in the record is retracted ¹, with no grounds available in what was consulted here.
5. The studied population is narrow. Premenopausal women with a specific diagnosis, at one dose, by one route ^4,5. Use outside that has no supporting evidence in this file.
6. Sponsor involvement runs through the primary literature. The pivotal trials, the extension, the subgroup analyses and the safety review share author groups ^4,5,6,10,11. Disclosure practice appears standard for the field; the concentration is still a limitation, and the substantive critiques come from outside those groups ^7,8,17.
7. No head-to-head trial against flibanserin was located, despite the two being the only approved options for the same indication ¹⁸ and being critiqued together ⁸.
8. Long-term efficacy data are open-label ⁶. Fifty-two weeks of follow-up without blinding answers safety questions better than efficacy ones.
9. The mechanism is a hypothesis. Excitatory brain pathways are proposed rather than demonstrated in the sources cited ¹⁴.
10. This guide has read abstracts, not full texts — including for RECONNECT and for both re-analyses. The numbers and characterisations reported are those the abstracts state.
11. Nothing is known about non-pharmacy material sold under this name.

09 · References

1. Safarinejad MR. RETRACTED: Evaluation of the safety and efficacy of bremelanotide, a melanocortin receptor agonist, in female subjects with arousal disorder: a double-blind placebo-controlled, fixed dose, randomized study. J Sex Med. 2008 Apr;5(4):887–897.

   PMID 18179455 ↗

2. Clayton AH, Lucas J, DeRogatis LR, Jordan R. Phase I randomized placebo-controlled, double-blind study of the safety and tolerability of bremelanotide coadministered with ethanol in healthy male and female participants. Clin Ther. 2017 Mar;39(3):514–526.e14.

   PMID 28189361 ↗

3. Bremelanotide (Vyleesi) for hypoactive sexual desire disorder. Med Lett Drugs Ther. 2019 Jul 29;61(1577):114–116. No abstract available..

   PMID 31381550 ↗

4. Althof S, DeRogatis LR, Greenberg S, Clayton AH, Jordan R, Lucas J, Spana C. Responder analyses from a phase 2b dose-ranging study of bremelanotide. J Sex Med. 2019 Aug;16(8):1226–1235.

   PMID 31277966 ↗

5. Kingsberg SA, Clayton AH, Portman D, Williams LA, Krop J, Jordan R, Lucas J, Simon JA. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstet Gynecol. 2019 Nov;134(5):899–908.

   PMID 31599840 ↗

6. Simon JA, Kingsberg SA, Portman D, Williams LA, Krop J, Jordan R, Lucas J, Clayton AH. Long-term safety and efficacy of bremelanotide for hypoactive sexual desire disorder. Obstet Gynecol. 2019 Nov;134(5):909–917.

   PMID 31599847 ↗

7. Spielmans GI. Re-analyzing phase III bremelanotide trials for “hypoactive sexual desire disorder” in women. J Sex Res. 2021 Nov–Dec;58(9):1085–1105.

   PMID 33678061 ↗

8. Mintzes B, Tiefer L, Cosgrove L. Bremelanotide and flibanserin for low sexual desire in women: the fallacy of regulatory precedent. Drug Ther Bull. 2021 Dec;59(12):185–188. Review.

   PMID 34642243 ↗

9. Lee JH, Lee JE, Harsh V, Clayton AH. Pharmacotherapy for sexual dysfunction in women. Curr Psychiatry Rep. 2022 Feb;24(2):99–109. Review.

   PMID 35102537 ↗

10. Clayton AH, Kingsberg SA, Portman D, Sadiq A, Krop J, Jordan R, Lucas J, Simon JA. Safety profile of bremelanotide across the clinical development program. J Womens Health (Larchmt). 2022 Feb;31(2):171–182.

    PMID 35147466 ↗

11. Simon JA, Kingsberg SA, Portman D, Jordan R, Lucas J, Sadiq A, Krop J, Clayton AH. Prespecified and integrated subgroup analyses from the RECONNECT phase 3 studies of bremelanotide. J Womens Health (Larchmt). 2022 Mar;31(3):391–400.

    PMID 35230162 ↗

12. Zhong Q, Anderson Y. Management of hypertension with female sexual dysfunction. Medicina (Kaunas). 2022 May 5;58(5):637. Review.

    PMID 35630054 ↗

13. Burton CS, Mishra K. Pharmacologic therapeutic options for sexual dysfunction. Curr Opin Obstet Gynecol. 2022 Dec 1;34(6):402–408. Review.

    PMID 36036468 ↗

14. Cipriani S, Alfaroli C, Maseroli E, Vignozzi L. An evaluation of bremelanotide injection for the treatment of hypoactive sexual desire disorder. Expert Opin Pharmacother. 2023 Jan;24(1):15–21. Review.

    PMID 36242769 ↗

15. Sweeney P, Gimenez LE, Hernandez CC, Cone RD. Targeting the central melanocortin system for the treatment of metabolic disorders. Nat Rev Endocrinol. 2023 Sep;19(9):507–519. Review.

    PMID 37365323 ↗

16. Giliberto S, Shishodia R, Nastruz M, Brar C, Bulathsinhala S, Terry J, Pemminati S, Shenoy SK. A comprehensive review of novel FDA-approved psychiatric medications (2018–2022). Cureus. 2024 Mar 20;16(3):e56561. Review.

    PMID 38646400 ↗

17. Spielmans GI, Ellefson EM. Small effects, questionable outcomes: bremelanotide for hypoactive sexual desire disorder. J Sex Res. 2024 May;61(4):540–561. Review.

    PMID 36809187 ↗

18. Barakeh D, Mdaihly H, Karaoui LR. Pharmacotherapy of hypoactive sexual desire disorder in premenopausal women. Ann Pharmacother. 2025 Feb;59(2):148–161. Review.

    PMID 38767282 ↗

19. How A, Jowdy C, Novatcheva E, Clayton AH. Novel pharmacologic treatments of female sexual dysfunction. Clin Obstet Gynecol. 2025 Mar 1;68(1):10–14. Review.

    PMID 39846877 ↗

20. Fuhrman J, Yun J, Indorf A. Practical considerations and emerging approaches for the management of vasomotor and sexual symptoms in breast cancer patients on endocrine therapies. Expert Rev Clin Pharmacol. 2025 Oct;18(10):1–13. Review.

    PMID 41088800 ↗