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PT-141

Sexual HealthFDA-Approved

Last reviewed: May 24, 2026

Also Known As: Bremelanotide, Vyleesi, MC4R Agonist

Peptide Class: Cyclic Heptapeptide — Melanocortin Receptor Agonist (MC1R/MC3R/MC4R/MC5R)

Regulatory Status: FDA-approved as Vyleesi (June 2019) for premenopausal HSDD only. All other uses off-label. Not on WADA prohibited list.

What is PT-141?

PT-141 (bremelanotide, brand name Vyleesi) is a synthetic cyclic heptapeptide melanocortin receptor agonist developed by Palatin Technologies. It was derived from Melanotan II by removing the C-terminal amide group, eliminating the strong tanning effect while preserving sexual desire and arousal effects. The FDA approved PT-141 as Vyleesi in June 2019 for treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women — making it the first FDA-approved peptide that targets sexual desire through brain pathways rather than peripheral vascular mechanisms. Off-label use in men with erectile dysfunction is also documented. New to peptide research? Start with the basics →

Reported benefits:

  • FDA-approved for HSDD in premenopausal women (Vyleesi, June 2019)
  • Acts on central nervous system (MC3R/MC4R) rather than vascular system
  • ~45-minute onset, on-demand dosing
  • Erection support in men (off-label) including PDE5-resistant cases
  • No interaction with alcohol (unlike flibanserin)
  • Effects last 4–6 hours from a single dose

Common research dose: FDA-approved dose: 1.75 mg subcutaneously via Vyleesi autoinjector, ~45 minutes before anticipated sexual activity. Maximum 1 dose per 24 hours, maximum 8 doses per month.

Where to buy: PP maintains a vetted list of peptide vendors with verified discount codes. See Verified Discount Codes → for current options.

How does PT-141 work?

PT-141 is a non-selective melanocortin receptor agonist (MC1R–MC5R). At therapeutic doses, MC4R activation in the central nervous system is the clinically relevant mechanism — neurons expressing MC4R in hypothalamic and limbic regions modulate sexual desire and arousal. Unlike PDE5 inhibitors (Viagra) which work peripherally on vascular nitric oxide signaling, PT-141 acts centrally. This is the clinical rationale for use in cases where vascular drugs fail or are contraindicated.

  1. Melanocortin Receptor Agonism [1]. PT-141 is a non-selective agonist of melanocortin receptors (MC1R through MC5R, except MC2R which binds full ACTH). At therapeutic doses, MC4R activation is most clinically relevant — neurons expressing MC4R are present throughout the central nervous system, particularly in hypothalamic and limbic regions involved in sexual arousal.
  2. Central vs Peripheral Mechanism [2]. Unlike PDE5 inhibitors (sildenafil, tadalafil) which work peripherally on vascular nitric oxide signaling, PT-141 acts centrally to enhance sexual desire and arousal. This is the clinical rationale for use in cases where vascular drugs fail or are contraindicated.
  3. Dopamine Pathway Activation. Mechanistic studies suggest MC4R activation in hypothalamic circuits enhances dopamine signaling linked to sexual desire. The exact downstream pathway by which Vyleesi improves HSDD is not fully characterized in the FDA labeling.
  4. Cyclic Heptapeptide Structure. PT-141 is a cyclic 7-amino-acid peptide derived from melanotan II. The cyclization confers metabolic stability. Removal of the C-terminal amide compared to melanotan II eliminates the strong melanocyte-stimulating effect (tanning), while preserving sexual response.
  5. Pharmacokinetics. Subcutaneous bioavailability ~100%. Peak plasma levels ~1 hour post-injection. Plasma half-life 2.7 hours (range 1.9–4.0). Effects on sexual desire last 4–6 hours.

What is PT-141 used for?

PT-141's FDA-approved indication is hypoactive sexual desire disorder (HSDD) in premenopausal women — the Vyleesi label, June 2019. Off-label uses include male erectile dysfunction (particularly PDE5-resistant cases), postmenopausal HSDD, and SSRI-induced sexual dysfunction. A weight-loss side effect has also been observed (MC4R agonism modulates appetite — setmelanotide, another MC4R agonist, is FDA-approved for rare types of obesity).

  1. Premenopausal HSDD [3]. FDA approval indication. Two identical Phase 3 clinical trials (n=1,202 total premenopausal women with HSDD) showed Vyleesi improved sexual desire and reduced sexual distress vs placebo. Approval granted June 2019.
  2. Male Erectile Dysfunction (Off-Label) [4]. Earlier intranasal PT-141 trials in men with ED showed 34% achieving erection sufficient for intercourse vs 9% on placebo. Combination studies with sildenafil showed stronger erectile response than either drug alone — basis for off-label 'Viagra reboot' protocols in PDE5-resistant patients.
  3. Postmenopausal HSDD (Off-Label). Vyleesi is FDA-approved only for premenopausal women, but clinical practice has extended use to postmenopausal patients. Small case series report favorable outcomes; formal trials in this population are limited.
  4. SSRI-Induced Sexual Dysfunction (Off-Label). Off-label use for restoring sexual function in patients with SSRI-related sexual side effects. Limited published evidence but reported clinically.
  5. Calorie Reduction Side Effect. A trial analysis found obese women on PT-141 reduced calorie intake and lost weight. Setmelanotide, another MC4R agonist, is FDA-approved for rare types of obesity — suggesting MC4R agonism has appetite-modulating effects.

How long does PT-141 take to work?

PT-141 is on-demand, not daily — effects develop on a per-dose basis. Subjective effects on sexual desire and arousal typically peak around 45–60 minutes after subcutaneous injection. Effects last 4–6 hours per dose. The FDA-approved Vyleesi label requires assessment of efficacy at 8 weeks; if no improvement in sexual desire and distress, treatment should be discontinued.

PT-141 is on-demand, not daily. Subjective effects on sexual desire and arousal typically peak around 45–60 minutes after subcutaneous injection. Effects last 4–6 hours per dose. The FDA-approved Vyleesi label requires assessment of efficacy at 8 weeks of intermittent use; if no improvement in sexual desire and distress, treatment should be discontinued. Unlike flibanserin (which requires continuous daily dosing), PT-141 is purely on-demand and does not require cumulative dosing for effect.

How is PT-141 dosed?

PT-141 is administered as a subcutaneous injection on-demand. The FDA-approved Vyleesi product comes pre-dosed in an autoinjector (1.75 mg). Research-grade PT-141 is sold as lyophilized powder for reconstitution. Standard dose is 1.75 mg ~45 minutes before anticipated activity. Maximum 1 dose per 24 hours; maximum 8 doses per month (hyperpigmentation risk limit).

  1. FDA-approved (Vyleesi). 1.75 mg subcutaneously, ~45 minutes before anticipated sexual activity. Maximum 1 dose per 24 hours, maximum 8 doses per month.
  2. Research-grade typical range. 1–2 mg subcutaneously per dose.
  3. Lower starting dose. 1 mg (or even 250–500 mcg) for first-time use to test tolerance — particularly to assess nausea response.
  4. Off-label male ED protocol. 1.75–2 mg SC, 30–60 minutes before activity. Some clinicians combine with low-dose sildenafil (25 mg) for PDE5-resistant cases.
  5. Discontinuation. Per FDA label, discontinue if no improvement in sexual desire and distress after 8 weeks of use.

PT-141 is strictly on-demand, NOT a daily medication. Repeated dosing greater than 8 times per month increases hyperpigmentation risk. Always allow at least 24 hours between doses.

Need to calculate your dose? Convert mg to syringe units and plan reconstitution with the dosage calculator →.

How is PT-141 administered?

PT-141 is given as a subcutaneous injection — under the skin, not into muscle — on-demand ~45 minutes before anticipated sexual activity. The Vyleesi autoinjector is pre-dosed at 1.75 mg. Research-grade material requires reconstitution. For the practical mechanics of insulin syringes for research-grade material, see the syringes and injection technique guide.

  1. Route. Subcutaneous injection. Vyleesi autoinjector targets the abdomen or thigh.
  2. Time of day. ~45 minutes before anticipated sexual activity. On-demand only — not daily.
  3. With or without food. Either is fine. Eating a light snack before may help reduce nausea.
  4. Maximum frequency. 1 dose per 24 hours; maximum 8 doses per month (hyperpigmentation risk limit).
  5. Vyleesi autoinjector. Pre-dosed at 1.75 mg, no reconstitution required.
  6. Anti-nausea prep (optional). Some users take oral ondansetron 30 minutes before injection. Light snack with light protein also helps.
  7. Storage of reconstituted solution. Refrigerate at 2–8°C, use within 30 days, never freeze.

Timing context. PT-141 is fundamentally different from daily peptides — it's on-demand, taken before anticipated activity. The 45-minute pre-dose timing aligns with peak plasma levels and central nervous system effect onset. Effects last 4–6 hours, then resolve. There's no cumulative dosing or steady-state — each dose is independent. The 8-dose-per-month limit is the practical constraint, driven by hyperpigmentation risk rather than tolerance.

AspectRecommendation
FrequencyOn-demand only — max 1/24hr, max 8/month
Best time~45 minutes before anticipated activity (peak plasma timing)
FoodNo fasting requirement; light snack may help reduce nausea
Injection site rotationVyleesi: abdomen or thigh (per autoinjector instructions)
Half-life~2.7 hours; effects on sexual desire last 4–6 hours
Steady-stateNot applicable — each dose is independent (on-demand pharmacology)

Reconstitution math. Choose your bacteriostatic water volume based on dose precision. PT-141 research vials are typically 10 mg. The 1.75 mg FDA-approved dose maps cleanly to standard reconstitution volumes. All units below are measured on a U-100 insulin syringe (100 units = 1 mL). The table assumes a 10 mg vial.

BAC waterConcentration0.5 mg dose1 mg dose1.75 mg (FDA)2 mg dose
1 mL10 mg/mL5 units10 units18 units20 units
2 mL5 mg/mL10 units20 units35 units40 units
3 mL3.33 mg/mL15 units30 units53 units60 units

Units vs mcg. At a 10 mg vial, each unit drawn delivers 100 mcg of PT-141 at 1 mL reconstitution, 50 mcg at 2 mL, and 33 mcg at 3 mL — the reconstitution volume determines the mcg-per-unit conversion. For a primer on reading insulin syringes and choosing the right barrel size, see our guide on syringes and injection technique.

What does PT-141 stack well with?

PT-141's most-studied off-label combination is with sildenafil in PDE5-resistant ED — research data shows stronger erectile response than either alone. Cardiovascular monitoring required. Oxytocin is anecdotally combined for the emotional-bonding aspect of intimacy. The most important non-stacking is Melanotan II — both act on melanocortin receptors, additive nausea/BP/hyperpigmentation risk.

  1. Sildenafil (off-label, men). Combination shows stronger erectile response than either alone in research data. Used in PDE5-resistant ED. Cardiovascular risk additive — requires medical screening.
  2. Oxytocin. Anecdotally combined for emotional bonding aspect of intimacy. Limited research on combination but generally considered safe.
  3. BPC-157. BPC-157 — different mechanism (healing/gut). No direct interaction.
  4. Avoid: Melanotan II. Melanotan II — both act on melanocortin receptors. Stacking increases nausea, blood pressure changes, and hyperpigmentation risk.
  5. Anti-nausea protocol. Some users take oral ondansetron 30 minutes before injection. Ginger tablets are a non-prescription alternative.

What are the side effects of PT-141?

Nausea is the most common side effect (~40% in Phase 3 — major tolerability issue). Flushing (~20%) and injection site reactions (~13%) are also common. Less common moderate effects include headache, dizziness, vomiting. The most concerning serious risks are hyperpigmentation (focal skin darkening that may not resolve after stopping — driver of the 8-doses/month limit) and transient blood pressure elevation (6 mmHg systolic, 3 mmHg diastolic — contraindicated in uncontrolled hypertension).

Common (most users)

  1. Nausea. Most common side effect, occurs in ~40% of users in Phase 3 trials. Often most pronounced with first dose; many users find it tolerable after 1–2 doses or manageable with anti-nausea medication.
  2. Flushing. Facial warmth and redness in ~20% of users, usually mild and transient.
  3. Injection site reactions. Redness, pain, swelling in ~13% of users.

Less common (moderate)

  1. Headache (~11%) and dizziness.
  2. Vomiting (~5%), cough (~3%), fatigue (~3%).
  3. Hot flashes, paresthesia, mild nasal congestion.

Serious (rare)

  1. Hyperpigmentation. Focal skin darkening on face, gums, or breasts. Risk increases with frequent use (>8 doses per month). May not resolve after discontinuation.
  2. Transient blood pressure elevation. Average 6 mmHg systolic, 3 mmHg diastolic. Contraindicated in uncontrolled hypertension and cardiovascular disease.
  3. Rare acute liver injury. Single case of acute hepatitis after 10 doses over a year reported (LiverTox classification: D — possible rare cause).

PT-141 is contraindicated in patients with uncontrolled hypertension or cardiovascular disease due to transient blood pressure rises. The 8-doses-per-month limit exists to minimize hyperpigmentation risk — exceeding it raises the chance of skin darkening that may persist after stopping the drug. PT-141 reduces oral absorption (bioavailability) of certain medications (e.g., naltrexone, indomethacin) by slowing gastric motility. Pregnancy contraindicated based on animal teratogenicity data.

Does PT-141 interact with other drugs?

PT-141's most important interactions are with oral medications affected by slowed gastric motility (naltrexone, indomethacin — schedule away from PT-141 doses), antihypertensives (PT-141 raises BP transiently), other melanocortin agonists (additive side effects — avoid Melanotan II and setmelanotide), and PDE5 inhibitors (off-label combination shows stronger erectile response — cardiovascular monitoring required). Alcohol has minimal interaction.

  1. Naltrexone, indomethacin, and other oral medications. PT-141 slows gastric motility, reducing oral bioavailability of these drugs. Schedule oral meds away from PT-141 doses.
  2. Antihypertensives. PT-141 raises blood pressure transiently. Effects on patients on BP medications are unpredictable; medical supervision recommended.
  3. Other melanocortin agonists (Melanotan II, setmelanotide). Additive side effects. Avoid combination.
  4. Alcohol. Minimal interaction (unlike flibanserin). Safe in moderate amounts.
  5. PDE5 inhibitors (sildenafil, tadalafil). Off-label combination shows stronger erectile response in men. Cardiovascular monitoring required.

How should PT-141 be stored?

  1. Vyleesi autoinjector: refrigerate at 2–8°C in original carton until use. Do not freeze.
  2. Lyophilized research-grade powder: Store at -20°C for long-term storage; refrigerate at 2–8°C for short-term.
  3. Reconstituted solution: Store at 2–8°C; use within 30 days.
  4. Reconstitute with bacteriostatic water for injection (BAC water). Swirl gently — do not shake.
  5. Never freeze reconstituted solution. Protect from light.
  6. Discard if cloudy, discolored, or contains particles.

What are the limitations of PT-141 research?

PT-141 (Vyleesi) is FDA-approved ONLY for acquired, generalized HSDD in premenopausal women. ALL OFF-LABEL USES (male ED, postmenopausal HSDD, SSRI-induced dysfunction) are not FDA-approved. Researchers have questioned the relevance and effect sizes of the Phase 3 rating scales. Contraindicated in pregnancy (animal teratogenicity), uncontrolled hypertension, and cardiovascular disease. Hyperpigmentation risk increases beyond 8 doses/month and may not resolve after stopping. NOT WADA-prohibited.

PT-141 (brand name Vyleesi) is FDA-approved ONLY for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. The FDA labeling specifically excludes men, postmenopausal women, and use to enhance sexual performance.

ALL OFF-LABEL USES — including male ED, postmenopausal HSDD, and SSRI-induced dysfunction — are not FDA-approved. Off-label prescribing is legal under physician judgment but lacks the controlled trial evidence supporting the approved indication.

Researchers have questioned the relevance and effect sizes of the rating scales used in Phase 3 trials. The drug's clinical benefit was statistically significant but considered modest by some reviewers. Treatment should be discontinued after 8 weeks if no improvement in sexual desire and distress.

PT-141 is contraindicated in pregnancy (animal teratogenicity), uncontrolled hypertension, and cardiovascular disease. Hyperpigmentation risk increases with use beyond 8 doses per month and may not resolve after stopping the drug.

The World Anti-Doping Agency does not currently include PT-141 on the prohibited list.

Where to source PT-141

PT-141 is FDA-approved as Vyleesi — prescription, premenopausal women with HSDD only — distributed through specialty pharmacies. Off-label and research-grade PT-141 is sold by specialty peptide vendors. The vendors highlighted below have been vetted for transparent third-party testing, traceable batch documentation, and verified discount codes — including a nasal-format option (the original PT-141 delivery route in early clinical trials).

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PT-141 FAQ

Is PT-141 FDA-approved?

Yes — PT-141 (brand name Vyleesi, made by Palatin Technologies) is FDA-approved as of June 2019 for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. It is the first FDA-approved peptide acting on sexual desire through brain pathways. Use in men, postmenopausal women, or for sexual performance enhancement is OFF-LABEL.

How does PT-141 differ from Viagra?

Completely different mechanisms. Viagra (sildenafil) is a PDE5 inhibitor that works peripherally on vascular nitric oxide signaling — it improves blood flow but doesn't affect desire. PT-141 acts centrally on melanocortin receptors (MC4R) in the brain to enhance sexual desire and arousal. PT-141 works in cases where Viagra fails (PDE5-resistant ED). Some clinicians combine the two off-label.

Will PT-141 work for men?

Vyleesi is not FDA-approved for men. However, off-label use in men with erectile dysfunction is documented. Earlier intranasal PT-141 trials showed 34% of men with ED achieved erection sufficient for intercourse vs 9% on placebo. Off-label combination with sildenafil produces stronger erectile response than either alone in PDE5-resistant cases.

What about the nausea?

Nausea is the most common side effect (~40% in Phase 3). It's usually mild to moderate and most pronounced with the first dose. Many users find it tolerable after 1–2 doses, or manageable with eating a light snack before injection or taking oral ondansetron 30 minutes prior. Starting with a lower dose (1 mg or 500 mcg) helps assess tolerance.

Why is there a monthly dose limit?

The 8-doses-per-month limit exists to minimize hyperpigmentation risk. Frequent PT-141 use can cause focal skin darkening on the face, gums, or breasts that may NOT resolve after stopping the drug. Using more than 8 doses per month substantially increases this risk.

How long do effects last?

Onset is ~45–60 minutes after subcutaneous injection. Peak effects on sexual desire and arousal occur around 1–2 hours. Total effect duration is 4–6 hours per dose. PT-141 is on-demand, not daily — take it before, not after, the activity window.

Can PT-141 cause blood pressure problems?

Yes — PT-141 causes transient blood pressure elevation averaging 6 mmHg systolic and 3 mmHg diastolic. It is contraindicated in uncontrolled hypertension and cardiovascular disease. Patients on antihypertensive medications should be monitored. The effect is transient and not expected to cause severe BP elevation when used at the standard 1.75 mg dose.

How is PT-141 different from Melanotan II?

Melanotan II is the predecessor compound — PT-141 was derived from Melanotan II by removing the C-terminal amide group, which eliminates the strong tanning effect while preserving the sexual desire and arousal effects. Melanotan II is primarily used for skin pigmentation (off-label tanning); PT-141 is specifically optimized for sexual response without the pigmentation. Do NOT stack the two — additive melanocortin receptor effects increase nausea, blood pressure changes, and hyperpigmentation risk.

Where can I buy PT-141?

The FDA-approved version (Vyleesi) is a prescription drug from specialty pharmacies — premenopausal women with HSDD only. Off-label and research-grade PT-141 is sold by specialty peptide vendors. PP maintains a list of vetted vendors with verified discount codes — see Verified Discount Codes →.

References

  1. Vyleesi (bremelanotide injection) FDA Prescribing Information. 2019. https://www.accessdata.fda.gov/drugsatfda_docs/label/2019/210557s000lbl.pdf
  2. Wikipedia. Bremelanotide. https://en.wikipedia.org/wiki/Bremelanotide
  3. Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials. Obstet Gynecol. 2019;134(5):899-908. https://pubmed.ncbi.nlm.nih.gov/31599840/
  4. Diamond LE, Earle DC, Rosen RC, et al. Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141. Int J Impot Res. 2004;16(1):51-9. https://pubmed.ncbi.nlm.nih.gov/14963471/
  5. Dhillon S, Keam SJ. Bremelanotide: First Approval. Drugs. 2019;79(14):1599-1606. https://pubmed.ncbi.nlm.nih.gov/31429064/
  6. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bremelanotide. NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK573221/

Published Studies

Plain-English summaries of the peer-reviewed studies behind the claims above. Click any title to read the source paper.

Annals of the New York Academy of Sciences / PubMed · 2003Paywalled
PT-141: A Melanocortin Agonist for the Treatment of Sexual Dysfunction →

Molinoff PB, Shadiack AM, Earle D, Diamond LE, Quon CY

The foundational review establishing PT-141's mechanism and clinical rationale. PT-141 was developed as a next-generation analog of Melanotan II with higher selectivity for MC4R — the melanocortin receptor subtype most involved in sexual behavior — and a better safety profile. The paper documents PT-141's central nervous system mechanism: unlike PDE5 inhibitors which increase blood flow to the genitals, PT-141 acts in the hypothalamus to modulate the neural pathways governing desire and arousal itself.

Obstetrics & Gynecology / PMC · 2019Open Access
Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder — Two Randomized Phase 3 Trials (RECONNECT) →

Kingsberg SA, Clayton AH, Portman D, et al.

The pivotal Phase 3 trials that led to FDA approval of bremelanotide (Vyleesi) in 2019. Two identical RCTs (RECONNECT 301 and 302) enrolled premenopausal women with HSDD. Bremelanotide 1.75mg subcutaneous significantly improved both the Female Sexual Function Index desire domain score and the Female Sexual Distress Scale compared to placebo at 24 weeks. Nausea was the most common adverse event (40% bremelanotide vs 1.3% placebo).

Obstetrics & Gynecology / PMC · 2019Open Access
Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder →

Kingsberg SA, et al. — RECONNECT Study Group

The 52-week open-label extension of the RECONNECT trials, examining bremelanotide's long-term safety and sustained efficacy. No new safety signals emerged over 52 weeks of continued use, and improvements in HSDD symptoms were maintained throughout the extension period. Critical for the FDA approval package.

PMC / Frontiers in Pharmacology · 2022Open Access
Bremelanotide for Female Sexual Dysfunction — Mechanism, Clinical Trials, and FDA Approval →

PMC Research Group

A comprehensive review covering bremelanotide's full development history, mechanism of action, and clinical evidence across both female and male sexual dysfunction. Covers PT-141's off-label use in men — including studies showing efficacy in sildenafil non-responders and a synergistic effect when combined with PDE5 inhibitors.

World Journal of Men's Health · 2021Open Access
Novel Emerging Therapies for Erectile Dysfunction — Bremelanotide Section →

World Journal of Men's Health Research Group

A review of PT-141's evidence for male erectile dysfunction. At 20mg intranasal dosing, PT-141 produced significantly greater duration of base rigidity ≥80% vs placebo. In men with ED non-responsive to sildenafil, 34% of the PT-141 group reported significantly better results vs 9% placebo.

Sexual HealthMelanocortin AgonistFDA-ApprovedOn-Demand

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