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PT-141 (Bremelanotide)
A melanocortin-receptor (MC4R) agonist peptide for low sexual desire. Important honest framing: unlike most 'research peptides', bremelanotide is an FDA-APPROVED prescription drug — Vyleesi, approved 2019 — for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, self-injected subcutaneously on-demand. It has real phase-3 RCTs (the RECONNECT program). The catch: the approved-trial benefit was statistically significant but small (a fraction of a point on desire scales), nausea is very common, and it transiently raises blood pressure. Grey-market 'PT-141' vials sold online are NOT the approved drug and are unregulated.
Prescription medication — not a dietary supplement
PT-141 is a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Most PT-141 studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2003–2026 with a typical study size of 684 participants.
Based on 24 studies · 3 meta-analyses · 13 RCTs · 704 total participants
Confidence
High confidenceBy outcome
An FDA-approved prescription drug (Vyleesi) backed by two phase-3 RECONNECT RCTs for HSDD, but the approved-trial benefit was statistically significant yet clinically small and contested.
19 rigorous studies
14 randomized trials · 3 meta-analyses · 3 systematic reviews
Our evidence rating for PT-141 is accountable to this entire body of rigorous research indexed in PubMed — not a hand-picked subset.
PubMed · as of Jul 2026
No trials currently enrolling · 3 completed on ClinicalTrials.gov
3 of the completed trials have posted results
Registered trials show research momentum for PT-141, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Aug 2026
PT-141 (bremelanotide, brand name Vyleesi) is a synthetic cyclic heptapeptide analogue of the neuropeptide alpha-melanocyte-stimulating hormone (alpha-MSH).
It is a non-selective melanocortin-receptor agonist whose therapeutically relevant action is at the melanocortin-4 receptor (MC4R), which is expressed centrally — predominantly in the medial preoptic area of the hypothalamus — where it is thought to modulate the excitatory (pro-sexual) arm of the central pathways governing sexual desire and arousal.
This is the rare entry in this library where the human evidence is genuinely strong enough to support an approved indication: in 2019 the US FDA approved bremelanotide, given as an on-demand 1.75 mg subcutaneous auto-injection, for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women.
Approval rested on the two identical phase-3 RECONNECT trials (studies 301 and 302; 1,267 women randomized), which met their coprimary endpoints — statistically significant increases in the Female Sexual Function Index desire-domain score and reductions in desire-related distress versus placebo — plus a 52-week open-label extension and a phase-2b dose-ranging study.
The honest caveat is magnitude: the on-treatment improvements were statistically significant but clinically small (a desire-domain change on the order of ~0.3 of a point), and an independent critical appraisal argued the real-world benefit barely exceeds placebo and that the indication and outcome measures were contested.
The development history is instructive: PT-141 was first studied as an INTRANASAL spray for erectile dysfunction in men (including a trial salvaging sildenafil non-responders) and for female sexual arousal disorder, but the program pivoted to the subcutaneous route for HSDD after melanocortin agonism was found to transiently raise blood pressure — ambulatory-BP studies showed small, short-lived increases in systolic/diastolic pressure with a compensatory drop in heart rate, which is why dosing is on-demand, capped, and contraindicated in uncontrolled hypertension or known cardiovascular disease.
Common adverse effects in the trials were nausea (very common, ~40% in the long-term extension), flushing, and headache; melanocortin (MC1R) activity can also cause focal skin hyperpigmentation.
Crucially, the approved product is a prescription drug, not a dietary supplement — and grey-market 'PT-141' vials sold 'for research' online are unregulated for identity, purity and sterility and are not the same as the approved medicine.
Because it is a prescription drug rather than a supplement to recommend, it is sandboxed out of goal-based and stack recommendations here.
Bremelanotide is an alpha-MSH analogue that non-selectively activates melanocortin receptors; its therapeutic action is attributed to agonism at MC4R, expressed centrally in the medial preoptic area of the hypothalamus, which modulates the excitatory (pro-sexual) pathways of sexual desire and arousal. This is the mechanism cited in the approval and the neurobiology reviews.
Animal work and human PK/PD studies suggest melanocortin agonism shifts the central excitation/inhibition balance toward sexual desire and arousal — in rodents PT-141 activates hypothalamic neurons (c-Fos) and induces pro-sexual behaviors, and in early human trials it produced erections in men and increased reported desire in women.
Non-selective melanocortin activation drives the characteristic adverse effects: MC1R agonism can cause focal skin/facial hyperpigmentation, and MC4R activity in cardiovascular control produces transient increases in blood pressure with a reflex fall in heart rate.
How PT-141 works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
The only population with an approved indication and supportive phase-3 RCT evidence — under prescription and clinical supervision.
Contraindicated with uncontrolled hypertension or known CVD due to the transient BP increase.
Not approved; earlier male-ED (intranasal) trials exist but the program moved to subcutaneous HSDD in premenopausal women. Off-label/grey-market use is unstudied for safety in these groups.
Avoid — not recommended in pregnancy or lactation.
Bremelanotide slows gastric emptying and can reduce the rate/extent of absorption of concomitant oral drugs. The labeling specifically warns it may significantly decrease absorption of oral naltrexone, potentially leading to subtherapeutic naltrexone levels — avoid co-administration with oral naltrexone-containing products; for other time-critical oral drugs, separate dosing.
Because the peptide transiently raises blood pressure, use in people on cardiovascular therapy requires caution and BP context; contraindicated with uncontrolled hypertension or CVD.
Combining with alcohol may worsen flushing and related vasomotor symptoms.
Tip: Most common adverse event (~40%); an antiemetic was sometimes used in trials. A frequent reason for discontinuation.
Tip: Common and usually transient.
Tip: Common; transient.
Tip: Rotate subcutaneous injection sites.
Tip: Small and short-lived in normotensive/controlled-hypertensive women; avoid in uncontrolled hypertension or CVD; respect dose caps.
Tip: More likely with repeated dosing and in darker skin; may not fully reverse.
PT-141 has an evidence score of 5/10 — moderate evidence based on 18 indexed studies, including 2 meta-analyses. A melanocortin-receptor (MC4R) agonist peptide for low sexual desire. Important honest framing: unlike most 'research peptides', bremelanotide is an FDA-APPROVED prescription drug — Vyleesi, approved 2019 — for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, self-injected subcutaneously on-demand. It has real phase-3 RCTs (the RECONNECT program). The catch: the approved-trial benefit was statistically significant but small (a fraction of a point on desire scales), nausea is very common, and it transiently raises blood pressure. Grey-market 'PT-141' vials sold online are NOT the approved drug and are unregulated. Representative study: PMID 40543759.
The commonly studied dose of PT-141 is Approved (Vyleesi): 1.75 mg subcutaneous, self-injected on-demand ~45 min before anticipated sexual activity; max 1 dose/24 h and 8 doses/month. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Timing is flexible for PT-141 — consistent daily use matters more than the time of day. Used on-demand, not on a daily schedule: a single subcutaneous dose ~45 minutes before anticipated sexual activity, with strict per-day and per-month caps.
PT-141 should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are nausea, flushing, headache. Use caution if any of these apply to you: Uncontrolled hypertension or known cardiovascular disease (transient BP increase); Pregnancy and breastfeeding; Not a dietary supplement — prescription-only; do not self-source grey-market vials.
Gonadorelin
Mostly mechanism / observationalA synthetic copy of gonadotropin-releasing hormone (GnRH), the hypothalamic decapeptide that drives the pituitary to release LH and FSH. Honest appraisal: it has genuine, trial-backed roles as a diagnostic agent (the GnRH/gonadorelin stimulation test) and — delivered in pulses by an infusion pump — for inducing ovulation in hypothalamic amenorrhea and spermatogenesis in men with congenital hypogonadotropic hypogonadism. Its now-trendy use in men's TRT clinics (compounded, to 'maintain testosterone/fertility' alongside testosterone, often replacing hCG) is largely off-label and has NOT been validated in controlled trials for that purpose.
Sermorelin
Mostly mechanism / observationalAn injectable analogue of growth-hormone-releasing hormone (the first 29 amino acids of GHRH) that stimulates the pituitary to release growth hormone. Honest appraisal: this WAS an FDA-approved prescription drug (Geref) with real human trials — for diagnosing GH deficiency and treating GH-deficient children — but it was discontinued commercially. Its current marketing as a compounded 'anti-aging' peptide is off-label and is NOT what those trials validated.
Argireline
Mostly mechanism / observationalA topical cosmetic peptide — a leave-on skincare ingredient, NOT something you swallow, inject, or take as a supplement, and NOT a drug. Argireline (acetyl hexapeptide-8, also sold as acetyl hexapeptide-3) is a six-amino-acid fragment modelled on the SNAP-25 protein. It is marketed as 'topical Botox' because, in cell systems, it interferes with the SNARE complex that nerve endings use to release neurotransmitter, in theory slightly relaxing the tiny muscle contractions that create expression lines. There ARE real human topical studies — small, short, vehicle-controlled split-face wrinkle trials — and they do show modest reductions in the appearance of fine lines. But the effect sizes are small, several of the trials are industry-linked, and this is a cosmetic effect on wrinkle APPEARANCE, not a health outcome. It is generally well tolerated on skin. This entry exists to describe a cosmetic ingredient honestly, not to recommend an ingestible supplement.
Kisspeptin
Mostly mechanism / observationalA hypothalamic neuropeptide (from the KISS1 gene) that sits at the top of the reproductive hormone axis — it stimulates GnRH neurons to release LH and FSH. It has a genuinely rigorous human-research record, largely from the Dhillo group at Imperial College London: kisspeptin-54 has been tested as an IVF egg-maturation trigger, in hypothalamic amenorrhea, and for sexual/emotional brain processing. Honest framing: this is legitimate investigational science, NOT an approved drug or a dietary supplement, and the grey-market 'libido peptide' sold online is not the supervised clinical product.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 25 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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