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PT-141

Bremelanotide · Vyleesi

PT-141 (bremelanotide, brand Vyleesi) is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone that acts as a non-selective melanocortin receptor agonist (chiefly MC4R/MC3R). It is FDA-approved as a 1.75 mg on-demand subcutaneous autoinjector for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, and has also been studied (historically intranasal) for male erectile dysfunction. Unlike PDE5 inhibitors it acts centrally on brain pathways governing sexual desire rather than on genital blood flow. The main risks are transient: it raises blood pressure and lowers heart rate, so it is used with caution and is inappropriate in uncontrolled hypertension or known cardiovascular disease; nausea is very common (~40%) and the leading reason for discontinuation; flushing and headache are common; and repeated/daily dosing (an off-label pattern) can cause focal skin and gum hyperpigmentation. It is not an anabolic steroid or SERM and has no androgenic or HPTA-suppressive activity. Gray-market PT-141 is unregulated and not verified equivalent to the tested product.

Clinical readoutPeptide · melanocortin
Hepatic strainLow
CardiovascularNone
HPTA suppressionNone
Half-life
2.7 h
Route
Subcutaneous injection
Evidence
A
Active
On-demand agent
2.7 h5.4 h8.1 h10.8 h13.5 h
Illustrative single-compartment washout · each mark = one half-life · t½ ≈ Terminal elimination half-life approximately 2.7 hours (reported range roughly 1.9-4.0 h) after a 1.75 mg subcutaneous dose (FDA clinical pharmacology data). Phase 1 human studies confirmed measurable systemic exposure after dosing.
Pharmacology

Mechanism of action

Bremelanotide is a synthetic analogue of alpha-MSH that non-selectively agonizes melanocortin receptors, with activity at MC4R and MC3R in the central nervous system. Activation of these hypothalamic/limbic melanocortin pathways is thought to modulate neural circuits governing sexual desire and arousal, producing a central (pro-desire) effect rather than the peripheral vascular effect of PDE5 inhibitors. The same receptor activity accounts for off-target effects: MC4R agonism underlies transient increases in blood pressure with reflex heart-rate reduction and nausea, while MC1R agonism drives melanogenesis (skin/mucosal darkening). Its mechanism is distinct from any steroid, androgen, or estrogen-receptor pathway, so it does not act on the hypothalamic-pituitary-gonadal axis.
Kinetics

Pharmacokinetics

Half-life

Terminal elimination half-life approximately 2.7 hours (reported range roughly 1.9-4.0 h) after a 1.75 mg subcutaneous dose (FDA clinical pharmacology data). Phase 1 human studies confirmed measurable systemic exposure after dosing.

Active duration

On-demand agent; typically self-administered about 45 minutes before anticipated sexual activity, with a short clinical window of hours. Label limits use to no more than one dose per 24 hours and no more than 8 doses per month.

Route

Subcutaneous injection (abdomen or thigh) via single-use autoinjector is the approved route; intranasal delivery was used in earlier/erectile-dysfunction trials but is not the marketed formulation.

Metabolism & clearance

Metabolized by hydrolysis of the peptide (amide) bonds rather than by cytochrome P450 to any major extent; elimination is via both renal and fecal routes. This PK profile is relevant for washout and monitoring timing, not for evading testing.

For monitoring and washout planning, not drug-test evasion.

Reported effects

Physiological & performance effects

  • Central increase in sexual desire and reduction in desire-related distress in premenopausal women with HSDD (modest effect size over placebo in phase 3 RCTs)
  • Statistically significant improvement in Female Sexual Function Index desire domain and reduction in Female Sexual Distress Scale scores versus placebo
  • In men with erectile dysfunction, enhanced erectile response, including as add-on to or salvage after sildenafil in earlier intranasal trials
  • Onset is not immediate arousal on-demand like a PDE5 inhibitor; benefit is measured over repeated as-needed use
  • Overall efficacy is modest and much of the treatment response overlaps with a large placebo effect seen across female sexual dysfunction trials
Safety

Adverse effects by system

Cardiovascular

Transient, small but statistically significant increases in systolic and diastolic blood pressure (SBP up to ~3 mmHg vs placebo on ambulatory monitoring, peaks typically lasting <15 min) accompanied by reductions in heart rate (~4-5 bpm at 1.75 mg). A subset of trial subjects discontinued for protocol-defined BP increases. Effects are generally not clinically important in healthy normotensives but warrant caution in those with cardiovascular risk.

Hepatic

No signal of hepatotoxicity in the clinical development program (3500 subjects, 43 studies); the drug is not appreciably hepatically metabolized. No reported cases of drug-induced liver injury.

Endocrine / HPTA

No known effect on the hypothalamic-pituitary-gonadal axis. Bremelanotide is a melanocortin peptide, not an androgen, anabolic steroid, estrogen, or SERM, and there is no evidence it suppresses endogenous testosterone, LH, or FSH. No adequate human data suggest HPTA involvement, and none is mechanistically expected.

Reproductive

Studied to improve sexual desire in premenopausal women; not an infertility or fertility-suppression agent. Contraindicated in pregnancy in the label (potential fetal harm/insufficient data); no evidence of a direct gonadal-toxic effect. No adequate human reproductive-outcome data beyond pregnancy precaution.

Neuropsychiatric

No consistent neuropsychiatric toxicity signal in RCTs. Headache is common but is a tolerability rather than psychiatric event. No adequate data indicating mood disorder induction.

Renal

No nephrotoxicity signal reported in trials; renal route contributes to elimination. Formal dosing guidance advises caution/avoidance in severe renal impairment due to altered exposure (label-based), but no renal injury has been attributed to the drug.

Hematologic

No clinically significant hematologic abnormalities reported across the clinical program; routine safety labs disclosed no meaningful changes. No adequate data suggesting hematologic toxicity.

Dermatologic

Flushing is common (~20%). Focal hyperpigmentation of the face, gingiva, and breasts can occur; it was rare with on-label intermittent dosing but developed in more than one-third of subjects given up to ~8-16 consecutive daily doses. Injection-site reactions occur in ~5%. Darkening may not fully reverse.

Recovery

HPTA suppression & recovery

Suppression: None expected / not applicable

Bremelanotide is a melanocortin peptide with no androgenic, anabolic, or estrogen-receptor activity and no demonstrated effect on the hypothalamic-pituitary-gonadal axis, so it does not cause HPTA suppression and no post-cycle recovery is anticipated. There is therefore no rationale for any SERM-based recovery protocol here. Anyone with concerns about testosterone, LH/FSH, or gonadal function should consult an endocrinologist for individualized evaluation rather than self-managing.

Bloodwork & vitals

Monitoring

Recommended labs & checks
Baseline and periodic blood pressure and heart rate (in-clinic and/or ambulatory)Cardiovascular risk assessment before initiationPregnancy testing where applicable before use in people who can become pregnantSkin/mucosal (gingiva, face, breast) exam for hyperpigmentation with repeated useGeneral clinical review of concomitant oral medications for absorption interactions

Cadence: Assess blood pressure and cardiovascular risk before starting and periodically during use; re-evaluate if dosing frequency increases or if symptoms arise. On-demand product, so monitoring is anchored to clinician follow-up rather than a fixed cycle.

Warning signs — seek care
  • Sustained or symptomatic high blood pressure (severe headache, chest pain, visual changes, shortness of breath)
  • Persistent or severe nausea or vomiting
  • New or spreading skin/gum darkening
  • Fainting, palpitations, or marked heart-rate changes
  • Any signs of an allergic or injection-site reaction; stop and seek care for severe or persistent symptoms
Do not use if

Contraindications

  • Uncontrolled hypertension
  • Known or clinically significant cardiovascular disease (including recent MI, stroke, or high cardiovascular risk)
  • Pregnancy (label contraindication; potential fetal harm and insufficient data)
  • Concurrent situations requiring frequent/daily dosing (increases hyperpigmentation and blood-pressure exposure)
  • Use more than once per 24 hours or more than 8 doses per month is not advised
  • Caution/avoidance in severe renal or hepatic impairment per labeling
  • Potential to lower plasma concentrations of orally administered drugs due to slowed gastric emptying (clinically shown with naltrexone and indomethacin)
Combinations

Interaction profile

  • ModerateWith another melanocortin agonist: Additive cardiovascular strain
  • ModerateWith a thermogenic stimulant: Additive hypertension
  • ContraindicatedWith DNP: Additive cardiovascular strain

Check a specific combination in the interaction checker.

Harm reduction

Reducing harm & when to stop

  • Have blood pressure and cardiovascular risk assessed by a clinician before use; do not use with uncontrolled hypertension or known cardiovascular disease.
  • Expect nausea (very common) and consider stopping if it is severe or persistent; nausea is the most common reason people discontinue.
  • Do not exceed one dose in 24 hours or 8 doses per month; frequent or daily dosing markedly increases risk of focal skin and gum hyperpigmentation and cumulative blood-pressure exposure.
  • Watch for new or spreading darkening of skin, gums, or breasts, which may not fully reverse.
  • Space oral medications appropriately, as bremelanotide can slow gastric emptying and reduce absorption of some oral drugs (e.g., naltrexone, indomethacin).
  • Gray-market or research-grade PT-141 is unregulated, may be impure or misdosed, and is not verified equivalent to the tested pharmaceutical product.
  • Seek urgent care for severe headache, chest pain, fainting, visual changes, or signs of a severe allergic reaction, and stop use.
  • This is not an anabolic/androgenic agent; do not expect and do not pursue muscle, strength, or body-composition effects, and do not combine with SERM 'recovery' protocols, which are irrelevant here. Discuss any hormonal concerns with an endocrinologist.
Evidence

Citations (9)

Every clinical claim above is tied to a primary source. Overall evidence grade A — graded to the best available evidence for its core claims.

  1. 01

    Two identical phase 3 double-blind placebo-controlled RCTs (RECONNECT) showed 1.75 mg subcutaneous on-demand bremelanotide significantly improved sexual desire and reduced desire-related distress in premenopausal women with HSDD; nausea, flushing, and headache were the most common adverse events.

    RCTBremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials.PMID 31599840 ↗

  2. 02

    Dose-finding RCT in premenopausal women found bremelanotide (1.25/1.75 mg) improved sexual function index and reduced distress versus placebo, with nausea, flushing, and headache as key adverse events.

    RCTBremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial.PMID 27181790 ↗

  3. 03

    Integrated safety review across the clinical development program (43 studies, ~3500 subjects) reported nausea 40.0% vs 1.3%, flushing 20.3% vs 1.3%, headache 11.3% vs 1.9%, injection-site reactions 5.4% vs 0.5%; nausea was the top discontinuation reason; focal hyperpigmentation was rare on-label but occurred in over one-third after up to ~16 consecutive daily doses; small transient BP increases occurred; interactions lowered naltrexone and indomethacin levels; caution advised in cardiovascular risk; no deaths.

    ReviewSafety Profile of Bremelanotide Across the Clinical Development Program.PMID 35147466 ↗

  4. 04

    Randomized ambulatory blood pressure monitoring showed bremelanotide produced small transient increases in SBP/DBP (~2-3 mmHg vs placebo, peaks typically <15 min) accompanied by heart-rate reductions (~4-5 bpm at 1.75 mg); some subjects discontinued for prespecified BP increases.

    RCTUsefulness of ambulatory blood pressure monitoring to assess the melanocortin receptor agonist bremelanotidePMID 27977473 ↗

  5. 05

    Phase 1 randomized crossover study established human pharmacokinetics/hemodynamics of bremelanotide (intranasal 20 mg) with and without ethanol, finding no clinically significant hypotensive or orthostatic effects and confirming systemic exposure.

    RCTPhase I Randomized Placebo-controlled, Double-blind Study of the Safety and Tolerability of Bremelanotide Coadministered With Ethanol in Healthy Male and Female Participants.PMID 28189361 ↗

  6. 06

    In men with erectile dysfunction who failed sildenafil, intranasal bremelanotide produced significantly higher positive clinical response (33.5% vs 8.5%) than placebo with more drug-related adverse effects.

    RCTPMID 18206919 ↗

  7. 07

    Co-administration of low-dose intranasal PT-141 with sildenafil in men with erectile dysfunction produced a significantly greater erectile response than sildenafil alone and was well tolerated.

    RCTPMID 15833522 ↗

  8. 08

    Meta-analysis of female sexual dysfunction trials (including bremelanotide) found ~68% of the treatment effect is accounted for by placebo, indicating modest true drug effect.

    Meta-analysisFemale Sexual Dysfunction and the Placebo Effect: A Meta-analysis.PMID 29995725 ↗

  9. 09

    RECONNECT exit surveys/interviews supported patient-reported benefit in desire and arousal with bremelanotide relative to placebo.

    RCTPMID 33538638 ↗

Last reviewed 2026-07-06 · Verified against PubMed · Educational, not medical advice