Dr. Pep

Peptides · Melanocortin receptor agonist

PT-141: what the studies show

Every line below comes from a study, label or regulator record, checked by two models, with the source linked. Information, not medical advice. For adults 18+.

What it is

  • PT-141 is the research name for bremelanotide, a melanocortin receptor agonist. The same molecule is the FDA-approved prescription drug Vyleesi.[1][2]
  • Bremelanotide activates several melanocortin receptors (MC1R, MC4R, MC3R, MC5R, MC2R, in order of potency). At therapeutic doses, MC1R and MC4R binding matter most. It is not the same as melanotan II or afamelanotide.[1]
  • The Vyleesi label (2025) approves it for premenopausal women with acquired, generalised hypoactive sexual desire disorder (HSDD) that is not due to another condition, relationship problems or a medication. It is not indicated for postmenopausal women, men, or to improve sexual performance.[1]

Bottom line

  • Bremelanotide is an approved on-demand injection with modest, statistically significant benefit on desire scores in premenopausal women, and frequent nausea and flushing. Its use in men or sold as 'PT-141' research vials is not approved.[3][1][4]

What the human studies found

  • RECONNECT (two identical RCTs, 1,267 premenopausal women with HSDD, 24 weeks, 1.75 mg subcutaneous as needed): compared with placebo, desire scores rose (FSFI-desire difference 0.35 in the combined analysis, p<0.001) and distress about low desire fell (-0.33, p<0.001). Nausea, flushing and headache each affected 10% or more.[3]
  • In the 52-week open-label extension, 684 women chose to continue, and 272 completed it. Treatment-related nausea was 40.4%, flushing 20.6% and headache 12.0%. The extension had no placebo group and used descriptive statistics only.[5]
  • A separate re-analysis of the FDA application data for the two phase 3 trials found similar efficacy but reported that stopping because of side effects was far higher on bremelanotide (odds ratio 11.98) and that fewer women on bremelanotide went on to the open-label study (odds ratio 0.30). It also said 72.72% of protocol-listed outcomes were not reported in the main paper. This is a single critic's analysis.[6]
  • Men (not an approved use): an RCT of intranasal bremelanotide 10 mg in 342 men with erectile dysfunction who did not respond to sildenafil reported a positive clinical result in 33.5% versus 8.5% on placebo, with more drug-related side effects.[7]
  • In early subcutaneous studies, healthy men (0.3 to 10 mg tested) had a significant erectile response at doses above 1 mg, and men with erectile dysfunction who responded poorly to Viagra had one at 4 mg and 6 mg (crossover, with visual sexual stimulation).[8]

Known risks and side effects

  • Phase 3 trials (label): nausea 40.0% versus 1.3% on placebo, flushing 20.3% versus 0.3%, injection-site reactions 13.2% versus 8.4%, headache 11.3% versus 1.9%, vomiting 4.8% versus 0.2%. Stopping because of side effects was 18% versus 2%, mostly from nausea (8%).[1]
  • Each dose briefly raises blood pressure (up to about 6 mmHg systolic and 3 diastolic, peaking 2-4 hours after the dose) and lowers heart rate by up to about 5 beats per minute. Ambulatory monitoring in 397 women showed rises of about 3 mmHg systolic after the 1.75 mg dose, lasting under 15 minutes at peak.[1][9]
  • Focal skin darkening (hyperpigmentation), including face, gums and breasts, occurred in 1% on up to 8 doses a month. In another study 38% developed it after 8 daily doses, and it was more likely in darker skin. Resolution was not confirmed in everyone.[1][4]

Legal status

  • FDA approved Vyleesi for premenopausal women with HSDD (label dated 2025).[1]
  • FDA warning letters dated 2026-08-24 to NuScience Peptides and Peptide Partners LLC named 'PT-141 (Bremelanotide)' sold as research peptides among unapproved new drugs.[2][10]

Sources

  1. [1] Vyleesi (Bremelanotide) Injection prescribing information
  2. [2] FDA: Warning Letter, NuScience Peptides LLC (2026-08-24), tesamorelin, ipamorelin, PT-141, retatrutide, survodutide, mazdutide
  3. [3] Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials.
  4. [4] Safety Profile of Bremelanotide Across the Clinical Development Program.
  5. [5] Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder.
  6. [6] Re-Analyzing Phase III Bremelanotide Trials for "Hypoactive Sexual Desire Disorder" in Women.
  7. [7] Salvage of sildenafil failures with bremelanotide: a randomized, double-blind, placebo controlled study.
  8. [8] Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141, a melanocortin receptor agonist, in healthy male subjects and in patients with an inadequate response to Viagra.
  9. [9] Usefulness of ambulatory blood pressure monitoring to assess the melanocortin receptor agonist bremelanotide.
  10. [10] FDA: Warning Letter, Peptide Partners LLC (2026-08-24), research-use-only semaglutide, tirzepatide, retatrutide, tesamorelin, PT-141