Human RCT
Mensch
Kingsberg SA. et al. 2019
Increase in self-reported sexual-desire scores versus placebo in randomised trials (RECONNECT)
What does NOT follow: Effect size small to moderate; study discontinuation due to nausea was common.
Peptide entry · Research other
Bremelanotide
PT-141 · Vyleesi
Highest evidence
Human RCT
Studies recorded
5· 5 in humans
Legal status · US
PrescriptionScientific context only. Not medical advice, not a recommendation to use.
At a glance
Synthetic cyclic heptapeptide acting as a non-selective melanocortin-receptor agonist. FDA-approved in 2019 as Vyleesi for hypoactive sexual desire disorder (HSDD) in pre-menopausal women.
Researched for
Hypoactive sexual desire disorder (HSDD) in womenErectile dysfunction (earlier phase-2 trials)
Official status
US: Prescription
FDA-approved 2019 as Vyleesi for HSDD in pre-menopausal women. Prescription-only.
Overview
What is it?
Synthetic cyclic heptapeptide acting as a non-selective melanocortin-receptor agonist. FDA-approved in 2019 as Vyleesi for hypoactive sexual desire disorder (HSDD) in pre-menopausal women.
How is it meant to work? →
Bremelanotide is a cyclic peptide that binds non-selectively to melanocortin receptors (MC1R through MC5R) — with highest affinity at MC4R in the central nervous system. The precise role of MC4R activation in sexual behaviour is …
What do studies show? →
Human RCTIncrease in self-reported sexual-desire scores versus placebo in randomised trials (RECONNECT)
What do users report? →
On drugs.com, bremelanotide (Vyleesi; as of June 2026) holds an average user rating of about 7.2–7.3 out of 10 — but from only around 40 reviews (64% positive, 21% negative). The recurring drawback named is mainly nausea; descriptions of the effect are mixed.⚠ anecdotal – not scientific evidence
01
Mechanism of action
Bremelanotide is a cyclic peptide that binds non-selectively to melanocortin receptors (MC1R through MC5R) — with highest affinity at MC4R in the central nervous system. The precise role of MC4R activation in sexual behaviour is not fully understood; animal data show effects on hypothalamic circuits. Peripheral effects (blood pressure, hyperpigmentation) are attributed to MC1R/MC2R.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
03
What the studies show
Human RCT
Mensch
Kingsberg SA. et al. 2019
Transient blood-pressure increase within hours after subcutaneous administration observed in the registration trials
What does NOT follow: Therefore contraindicated in uncontrolled hypertension or cardiovascular disease (FDA label).
Human trial
Mensch
Focal hyperpigmentation (freckle-like) was documented in several trials
What does NOT follow: Likely via MC1R activation; mostly reversible after discontinuation, but persistent cases described.
04
Where studies disagree
Open question
Is bremelanotide's libido effect clinically meaningful or mostly subjective and close to placebo?
POSITION A
The pivotal trials showed statistically significant improvements in hypoactive sexual desire disorder (HSDD).
POSITION B
The absolute effect sizes were small, the endpoints subjective and the placebo response high; nausea frequently led to discontinuation.
CURRENT STATE · Approved, but regarded as moderately effective with a notable tolerability trade-off.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 2.7 h. Pure pharmacokinetic model — not a dosing recommendation.
Open in PK tool →Start time: t₀ = 0h
Repeat interval: off (single dose)
06
Routes of administration in the literature
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Subcutaneous
In the RECONNECT trials administered as an auto-injector subcutaneously in the abdomen or thigh.
06b
Amounts reported in sources
Which amounts were reported in which source — ordered by context (approval, trial, animal model, secondary literature, community).
06c
Storage & stability
What prescribing information and stability literature report about storing the substance — descriptive, not a mixing or usage guide.
Reconstituted · storage
2–8 °C; limited storage below 30 °C is possible per the label.
Reconstituted · shelf life
Exact periods: see the prescribing information for the finished product (Vyleesi autoinjector).
What the stability literature describes
- •Keep protected from light.
- •Freezing is not provided for in the label.
06d
Safer use & risks
Risk notes for harm reduction — descriptive, not a usage or dosing guide.
This substance is approved (in at least one country) — use belongs in medical hands, within the approved indication and a physician-set dose.
Online numbers are not a benchmark
Amounts from TikTok, YouTube and forums are mostly imitation rather than data — and are often wrongly derived from animal studies (µg/kg). Not a reliable benchmark for humans.
Sterility & infection risk
Injection solutions prepared or stored non-sterile carry an infection and abscess risk. Contamination is common with grey-market product.
Unknown product quality
Research-/grey-market product is not quality-tested: identity, purity and actual content are often unknown, and counterfeits occur.
Mind interactions
Combinations with medications or pre-existing conditions can carry risks (see the Interactions section). Clarify with a doctor beforehand.
Warning signs — seek medical help
With persistent pain, redness/swelling at the injection site, fever, shortness of breath, racing heart, chest pain or allergic reactions, seek medical help immediately.
A doctor, not a forum
Concrete questions about use and amount belong in a conversation with a doctor — not in a comment thread.
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human RCT
Nausea
From aggregated RECONNECT trials; not to be read as an individual prediction.
≈40 % in RECONNECT
Human trial
Focal hyperpigmentation
Presumed MC1R-mediated; persistent cases described in the literature.
selten, persistierend möglich
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
ContraindicatedAntihypertensives / cardiovascular diseaseHuman RCT
Transient blood-pressure increase and heart-rate decrease after dosing; contraindicated per the label in uncontrolled hypertension or known cardiovascular disease.
Context: Contraindication per the label — risk reporting, not a combination guide.
CautionNaltrexone (oral)Human trial
Bremelanotide can significantly reduce the absorption of orally administered naltrexone — relevant for people taking naltrexone to treat dependence.
Context: Risk reporting from the label.
08
Risks & hygiene aspects in the literature
What regulatory and scientific literature reports on risks, sterility and identity in non-pharmaceutical sources — descriptive, not a hygiene guide.
Contraindication in cardiovascular disease
FDA label lists uncontrolled hypertension and known cardiovascular disease as contraindications due to the transient blood-pressure increase.
09
Regulatory voices
Direct statements from official assessment documents — paraphrased with date and source link.
FDAU.S. Food and Drug Administration
2019-06-21Press release on Vyleesi approval, June 2019.
The FDA strives to protect and advance the health of women.
10
Anecdotal observations
Weakest evidence tier — not supported by studies
Reading note. This section gathers popular claims from communities and forums. They are explicitly marked as weakest-tier evidence. Unblinded self-reports are particularly prone to placebo, recall and confirmation biases.
Why no amounts or protocols are listed here. We deliberately show only WHAT communities report — not in what amount or how it is used. Anecdotal "doses" or "biohacker protocols" are neither verified nor standardised nor safe; publishing them would be a usage guide, which we do not provide on principle. Specific amounts belong in a conversation with a doctor, not in a forum.
Nausea and facial flushing shortly after use are very commonly described.
consistent theme across experience reports
Not supported by studies: Consistent with the controlled trials, where nausea was the most common adverse effect; usually transient but a reason for discontinuation.
With repeated use, skin darkening and darker moles are reported.
recurring in forums, especially with frequent use
Not supported by studies: Mechanistically consistent with melanocortin activation (as documented for the related Melanotan II). Pigment changes can persist; they are not systematically tracked and warrant dermatological attention.
10b
What online communities discuss
Recurring themes from Reddit, Quora and patient forums — synthetically summarised, sources linked. Not scientific evidence, but a signal of what users report. Deliberately separated from the study base.
Non-scientific sources. What users report in forums — synthetically summarised, paraphrased, with link to source. Not validated by studies.
Sorted by discussion frequency · 1 Thema
11
Legal status by country
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
- 1Enter the vial's substance amount (printed on the label).
- 2Enter how much solvent you add.
- 3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.
Cofactors
These cofactors relate to the peptide class, not to a specific use. No recommendation, no dosing.
14
Study register
Human RCTRandomised controlled trialn = 1247
Kingsberg SA. et al. · 2019
Bremelanotide for hypoactive sexual desire disorder: two phase-3 trials (RECONNECT)
Concrete results
Responder rate on desire score
25.0% vs 17.0%
vs Placebo · 24 Wochen
Human trialControlled trial
Diamond LE. et al. · 2006
An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist
Human trialControlled trial
Rosen RC. et al. · 2004
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
Human RCTRandomised controlled trial
Clayton AH. et al. · 2016
Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial
15
Sources & method
Reviewed by
editor-placeholder
Last reviewed
2026-05-22
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