Peptide Evidence Index

PT-141 (Bremelanotide)

Evidence last reviewed: September 2026

Quick answers

What is it?: PT-141 (bremelanotide) is a synthetic peptide, sold as the FDA-approved drug Vyleesi, that activates melanocortin receptors in the brain to affect sexual desire.
Why are people interested in it?: It's the one compound in this library with genuine FDA approval and two large Phase 3 trials, but only for a specific diagnosis in premenopausal women — general libido or male sexual-performance use has not gone through that evidence.
What has actually been studied?: Two identically designed Phase 3 RECONNECT trials randomized 1,267 premenopausal women with hypoactive sexual desire disorder, followed by a 52-week open-label extension and a subgroup analysis; smaller trials have explored diabetic kidney disease and, combined with tirzepatide, obesity.
How strong is the evidence?: Approved medicine — approved by a major regulator for a specific use, backed by large placebo-controlled Phase 3 trials with a modest but consistent effect.
What don't we know yet?: Whether it has any meaningful effect in men or postmenopausal women, whether the modest average improvement is noticeable to most individual women, and long-term safety beyond about a year.
Where can I read the original research?: Sources at the bottom of this page: Kingsberg et al., 2019, Obstetrics & Gynecology; Simon et al., 2019, Obstetrics & Gynecology.

Plain-English overview

PT-141, also called bremelanotide, is a synthetic peptide that activates melanocortin receptors in the brain, mainly MC4R. It grew out of the same melanocortin-agonist research program that produced the tanning peptide melanotan II, after researchers noticed it affected sexual arousal during early testing. Unlike nearly everything else in this library, PT-141 is an FDA-approved prescription medicine: approved in 2019 under the brand name Vyleesi, it is indicated specifically for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women — a persistent, distressing loss of sexual desire not better explained by another medical, relationship, or psychiatric cause. It is not approved for men, for postmenopausal women, or as a general libido enhancer, even though it is sometimes discussed for those uses. Its approval rests on a program of ten registered clinical trials, including two large Phase 3 trials (RECONNECT) that randomized 1,267 premenopausal women with HSDD. Smaller, later trials have explored other, unapproved uses, including diabetic kidney disease and, combined with the GLP-1/GIP drug tirzepatide, obesity.

What researchers are studying it for

hypoactive sexual desire disorder in premenopausal women (FDA-approved use)
female sexual arousal disorder (studied, not an approved use)
diabetic kidney disease (small Phase 2b trial)
obesity, in combination with tirzepatide (ongoing Phase 2 trial)

Current evidence level

Randomized trials

Regulatory status: Approved medicine. Evidence strength and approval are scored separately; approval is a regulatory decision about a specific use, not a measure of how much research exists.

Human research

PT-141's approval rests on two identically designed Phase 3 trials, together called RECONNECT, that randomized 1,267 premenopausal women with HSDD to bremelanotide or placebo for 24 weeks (Kingsberg et al., 2019, Obstetrics & Gynecology). Women self-administered a single fixed subcutaneous dose as needed before anticipated sexual activity. Across both trials, women taking bremelanotide had statistically significant increases in a validated measure of sexual desire and significant reductions in distress about low desire, compared with placebo, with modest but consistent effect sizes across both trials. The most common side effects were nausea, flushing, and headache, each occurring in 10% or more of participants; nausea was the most frequent and the main reason some women stopped treatment. A 52-week open-label extension found no new safety signals and showed the desire and distress improvements were sustained in the 684 of 856 eligible women who continued (Simon et al., 2019, Obstetrics & Gynecology). A later subgroup analysis found the benefit held up across age, weight, BMI, and contraceptive-use subgroups (Simon et al., 2022, Journal of Women's Health). The approved dose itself was established before Phase 3 began: a Phase 2 dose-finding trial in 612 premenopausal women with sexual arousal and/or desire disorders (2011–2012) compared several fixed subcutaneous dose levels against placebo before a single dose was carried forward into the pivotal trials (NCT01382719). Beyond the pivotal HSDD program, ten trials of bremelanotide are registered in total on ClinicalTrials.gov, sponsored mainly by Palatin Technologies, the drug's originator, and its former marketing partners. Later and smaller trials have explored other, unapproved uses: a small Phase 2b trial in diabetic kidney disease measuring urinary protein and podocyte (kidney filter cell) markers in 16 participants, completed in 2024 (NCT05709444), and an ongoing Phase 2 trial combining bremelanotide with the GLP-1/GIP drug tirzepatide for obesity in 108 participants, active as of 2026 with no results yet (NCT06565611). Neither of these newer uses has completed Phase 3 testing or received any regulatory approval.

Animal and preclinical research

Not covered in the published research we reviewed; the source material for this profile addresses bremelanotide's clinical development program, not its preclinical or animal pharmacology.

Major findings

Two Phase 3 RECONNECT trials in 1,267 premenopausal women found statistically significant increases in sexual desire and reductions in distress about low desire compared with placebo.
Effect sizes were modest but consistent across both trials.
The most common side effects were nausea, flushing, and headache, each occurring in 10% or more of participants; nausea was the main reason some women stopped treatment.
A 52-week open-label extension found no new safety signals and sustained desire and distress improvements.
A subgroup analysis found the benefit held up across age, weight, BMI, and contraceptive-use subgroups.
A Phase 2 dose-finding trial in 612 women established the dose later tested in Phase 3.
Ten trials of bremelanotide are registered on ClinicalTrials.gov in total, sponsored mainly by Palatin Technologies, spanning the approved HSDD indication and newer, unapproved investigations.

What has not been established

Whether bremelanotide has any meaningful effect in men or in postmenopausal women — neither population was included in the pivotal trials.
Whether the modest average improvement seen in trials translates into a difference most individual women would notice.
Long-term safety beyond about a year of use, since the open-label extension ran 52 weeks.
Whether bremelanotide's melanocortin-receptor effects on blood pressure carry any risk with repeated use, particularly alongside other cardiovascular medications.
Whether the ongoing kidney-disease and obesity research will replicate in larger, controlled trials.

Important limitations

The diabetic kidney disease trial was small (16 participants).
The obesity trial combining bremelanotide with tirzepatide is ongoing with no results yet.
Pivotal trials enrolled only premenopausal women, so findings don't extend to men or postmenopausal women.
Neither newer use (kidney disease, obesity) has completed Phase 3 testing or received regulatory approval.
The newer diabetic-kidney-disease and obesity trials are small or still ongoing, so any findings from them are preliminary.

Regulatory status

FDA-approved since 2019, marketed as Vyleesi, for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. Not approved for men, for postmenopausal women, or for any other indication. It is chemically related to, but a distinct and separately regulated molecule from, the unapproved tanning peptide melanotan II.

Primary research sources

Kingsberg et al., "Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials": Obstetrics & Gynecology, 2019; DOI: 10.1097/AOG.0000000000003500
Simon et al., "Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder": Obstetrics & Gynecology, 2019; DOI: 10.1097/AOG.0000000000003514
Simon et al., "Prespecified and Integrated Subgroup Analyses from the RECONNECT Phase 3 Studies of Bremelanotide": Journal of Women's Health, 2022; DOI: 10.1089/jwh.2021.0225
Phase 3 trial of bremelanotide in premenopausal women with HSDD (Study 302): ClinicalTrials.gov; NCT02338960, n=714, completed 2017
Phase 3 trial of bremelanotide in premenopausal women with HSDD (Study 301): ClinicalTrials.gov; NCT02333071, n=723, completed
Phase 2 dose-finding trial in FSAD and/or HSDD: ClinicalTrials.gov; NCT01382719, n=612, completed 2012
Bremelanotide in diabetic kidney disease: ClinicalTrials.gov; NCT05709444, Phase 2b, n=16, completed 2024
Bremelanotide + tirzepatide for obesity: ClinicalTrials.gov; NCT06565611, Phase 2, n=108, active as of 2026

Full evidence entry (complete data, registry records, dosing evidence)

Approved medicine

Approved by a major regulator for a specific use

At a glance

Also known as: Bremelanotide, PT-141, Vyleesi (brand name)
Class: Synthetic cyclic heptapeptide, melanocortin receptor agonist
Derived from: A synthetic analogue of alpha-melanocyte-stimulating hormone (α-MSH), developed out of the same melanocortin-agonist research program that produced the tanning peptide melanotan II
Registered human trials: 10
…with published results: At least 5, including the two pivotal Phase 3 RECONNECT trials and the Phase 2 dose-finding study that preceded them
Largest human trial: 1,267 premenopausal women randomized across the two identically designed Phase 3 RECONNECT trials (2015-2017), the basis for FDA approval
Studied for: hypoactive sexual desire disorder in premenopausal women (FDA-approved use), female sexual arousal disorder (studied, not an approved use), diabetic kidney disease (small Phase 2b trial), obesity, in combination with tirzepatide (ongoing Phase 2 trial)
Dosing evidence: Prescribed by a clinicianVyleesi's dose is fixed by its FDA-approved label and administered under a prescriber's care for a specific diagnosis; the trials that supported approval tested that single dose in more than 1,200 women, and no dose has been established for any off-label use.
Regulatory status: FDA-approved since 2019, marketed as Vyleesi, for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. Not approved for men, for postmenopausal women, or for any other indication.

What it is

Unlike almost everything else in this library, PT-141 is an FDA-approved prescription medicine. Approved in 2019 under the brand name Vyleesi, it is indicated specifically for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women — a persistent, distressing loss of sexual desire not better explained by another medical, relationship, or psychiatric cause. It is not approved for men, for postmenopausal women, or as a general libido enhancer.

What the studies actually found

PT-141's approval rests on two identically designed Phase 3 trials, known together as RECONNECT, that randomized 1,267 premenopausal women with HSDD to bremelanotide or placebo for 24 weeks (Kingsberg et al., 2019, Obstetrics & Gynecology). Women self-administered a single fixed subcutaneous dose as needed before anticipated sexual activity.

Across both trials, women taking bremelanotide had statistically significant increases in a validated measure of sexual desire and significant reductions in distress about low desire, compared with placebo. The effect sizes were modest but consistent across both trials.

The most common side effects were nausea, flushing, and headache, each occurring in 10% or more of participants — nausea was the most frequent and the main reason some women stopped treatment. A 52-week open-label extension found no new safety signals and showed the desire and distress improvements were sustained in women who continued (Simon et al., 2019, Obstetrics & Gynecology). A later subgroup analysis found the benefit held up across age, weight, BMI, and contraceptive-use subgroups (Simon et al., 2022, Journal of Women's Health).

What exists in humans

Ten trials of bremelanotide are registered on ClinicalTrials.gov, sponsored mainly by Palatin Technologies — the drug's originator — and its former marketing partners. Beyond the pivotal HSDD program, later and smaller trials have explored other uses: a small Phase 2b trial in diabetic kidney disease measuring urinary protein and podocyte markers (16 participants, completed 2024), and an ongoing Phase 2 trial combining bremelanotide with the GLP-1/GIP drug tirzepatide for obesity. Neither of these newer uses has completed Phase 3 testing or received any regulatory approval.

What doses have been studied in humans

Because Vyleesi is an FDA-approved medicine, its dose is set by the approved label and administered under a prescriber's guidance — nothing here substitutes for that.

The approved dose was established well before Phase 3: a Phase 2 dose-finding trial in 612 premenopausal women with sexual arousal and/or desire disorders (2011–2012) compared several fixed subcutaneous dose levels against placebo before a single dose was carried forward. The two Phase 3 RECONNECT trials then tested that one fixed dose, self-administered subcutaneously as needed before sexual activity, in 1,267 women over 24 weeks, with 684 continuing into a 52-week open-label extension.

None of this dosing evidence applies to the other uses bremelanotide is sometimes discussed for outside its approved indication — male sexual performance, general libido, or weight loss. Those uses have either not been tested in a completed trial, or, in the case of the ongoing obesity trial, have no published dose-response data yet.

What remains unknown

Whether bremelanotide has any meaningful effect in men, or in postmenopausal women — neither

population was included in the pivotal trials

Whether the modest average improvement seen in trials translates into a difference most individual

women would notice

Long-term safety beyond about a year of use, since the open-label extension ran 52 weeks
Whether bremelanotide's melanocortin-receptor effects on blood pressure carry any risk with repeated

use, particularly alongside other cardiovascular medications

Whether the ongoing kidney-disease and obesity research will replicate in larger, controlled trials

Registry and study records

Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials: PubMed · Kingsberg et al., 2019, Obstetrics & Gynecology. n=1,267 randomized (RECONNECT studies 301 + 302). DOI: 10.1097/AOG.0000000000003500
Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder: PubMed · Simon et al., 2019, Obstetrics & Gynecology. 52-week open-label extension, 684 of 856 eligible enrolled. DOI: 10.1097/AOG.0000000000003514
Prespecified and Integrated Subgroup Analyses from the RECONNECT Phase 3 Studies of Bremelanotide: PubMed · Simon et al., 2022, Journal of Women's Health. DOI: 10.1089/jwh.2021.0225
Phase 3 trial of bremelanotide in premenopausal women with HSDD (Study 302): ClinicalTrials.gov NCT02338960 · n=714, completed 2017, results posted
Phase 3 trial of bremelanotide in premenopausal women with HSDD (Study 301): ClinicalTrials.gov NCT02333071 · n=723, completed, results posted
Phase 2 dose-finding trial in FSAD and/or HSDD: ClinicalTrials.gov NCT01382719 · n=612, completed 2012, results posted
Bremelanotide in diabetic kidney disease: ClinicalTrials.gov NCT05709444 · Phase 2b, n=16, completed 2024
Bremelanotide + tirzepatide for obesity: ClinicalTrials.gov NCT06565611 · Phase 2, n=108, active as of 2026, no results yet

See the full Evidence Index →

Evidence last reviewed: September 2026. Peptide Proof reports what studies found. We do not give medical advice, dosing guidance, or treatment recommendations.