Melanocortin receptor agonist
Bremelanotide (PT-141)
aka PT-141 · bremelanotide · bremelanotide acetate · Vyleesi
- A low sexual desire in premenopausal women (FDA-approved)
- B libido / erections in men (off-label)
Goals: Libido & sexual health Compare with another peptide →
User reports
approximate — combined from two independent Reddit reads
Men 45–60
3 men aged 45–60
small sample · n = 3Outcome mixed 2 of 3 · negative 1 of 3
Benefits erection 2 of 3
Side effects insomnia 2 of 3 · flushing 1 of 3 · gi upset 1 of 3 · joint pain 1 of 3 · other 1 of 3
Why stopped side effects 1 of 3
All men
11 men
- Positive: 2 of 11 (18%)
- Mixed: 5 of 11 (45%)
- Negative: 2 of 11 (18%)
- No effect: 3 of 11 (27%)
| Item | Reports |
|---|---|
| Erection | 6 of 11 (55%) |
| Libido | 1 of 11 (9%) |
| Item | Reports |
|---|---|
| Flushing | 3 of 11 (27%) |
| Insomnia | 2 of 11 (18%) |
| Nausea | 2 of 11 (18%) |
| Other | 2 of 11 (18%) |
| Anxiety | 1 of 11 (9%) |
| GI upset | 1 of 11 (9%) |
| Heart rate up | 1 of 11 (9%) |
| Joint pain | 1 of 11 (9%) |
| Item | Reports |
|---|---|
| Side effects | 1 of 11 (9%) |
Everyone
15 people
- Positive: 2 of 15 (13%)
- Mixed: 8 of 15 (53%)
- Negative: 3 of 15 (20%)
- No effect: 3 of 15 (20%)
| Item | Reports |
|---|---|
| Erection | 9 of 15 (60%) |
| Libido | 1 of 15 (7%) |
| Item | Reports |
|---|---|
| Flushing | 5 of 15 (33%) |
| Nausea | 3 of 15 (20%) |
| Other | 3 of 15 (20%) |
| GI upset | 2 of 15 (13%) |
| Insomnia | 2 of 15 (13%) |
| Anxiety | 1 of 15 (7%) |
| Heart rate up | 1 of 15 (7%) |
| Joint pain | 1 of 15 (7%) |
| Item | Reports |
|---|---|
| Side effects | 1 of 15 (7%) |
User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.
In their words
“Side effects: Mild stomach discomfort, facial flushing, some insomnia due to prolonged erections.”
“nothing for libido just crazy boners and no fucking sleep. I’m 52m”
“But joint pain and flu like symptoms.”
“Really felt nothing. No increased libido, sporadic boners or side effects.”
“Always with at least 24 hours between “experiments”. Started at .5mg and have tried all the way up to 2.5mg.”
“I got severe gas pain/stomach ache after the first hour that lasted off and on for an hour. Now I have restless aching legs.”
Read summaries and method notes
Read 1. Three qualifying men were found: two described stronger erections accompanied by unwanted effects, and one 52-year-old reported joint pain and flu-like symptoms without the benefit he had hoped for. The two responders included a man in his late 50s who experienced delayed, especially strong nighttime erections and another 52-year-old who reported insomnia. Among all 12 coded users, erection-related effects were the dominant reported benefit, whereas flushing and nausea were recurring adverse experiences. Other reports ranged from complete nonresponse to cardiovascular symptoms and anxiety. Effects often emerged hours after dosing rather than immediately, and the variability across users and sources makes the sample unsuitable for estimating treatment reliability.
Read 2. No stated age of 45–60. Three men: 1 positive (erection and libido on 0.5 mg, a quarter of the standard dose), 1 mixed (priapism for over 24 hours, would take under a quarter dose next time), 1 no effect (0.5 mg up to 2.5 mg). One woman had severe stomach and gas cramps, then restless aching legs. Small unstacked sample suggests a narrow window between no response and side effects.
Note 1. No actual diagnosed priapism was coded: prolonged erections and concern about priapism are not equivalent to a confirmed case. Stacking includes concurrent testosterone/HCG or other peptides when described. Reported doses are anecdotal and not dosing guidance. One nonresponse prompted questions about product quality, but a quality defect was not established. Only selected verifiable users were counted.
Note 2. Second-hand spouse/partner reports were excluded.
Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.
Summary
Cyclic heptapeptide melanocortin receptor agonist. FDA-approved 2019 as Vyleesi for acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women, not for male ED or general sexual enhancement. It activates multiple melanocortin receptors, but the label states that the mechanism producing clinical improvement in women is unknown; the detailed dopamine and nitric-oxide narrative is not an established human mechanism. Half-life 2.7 hours; duration of clinical effect after each dose is unknown, so predictable 24–72-hour subjective efficacy is not established. Off-label use in men for ED/low libido is supported only by early intranasal studies.
Proposed mechanism
- Activates melanocortin receptors: MC1R > MC4R > MC3R > MC5R; this receptor activity does not establish the clinical mechanism in women
- Proposed central action at MC4R in sexual-response circuits is mechanistic rationale rather than a proven human treatment pathway
- The previously detailed Gαs/Gαq, CREB, mesolimbic-dopamine and peripheral nitric-oxide pathway claims were not verified as the established human mechanism by the reviewed label and trials
Safety
- Nausea, flushing, headache and injection-site reactions
- Blood-pressure increase and heart-rate reduction
- Contraindicated with uncontrolled hypertension or known cardiovascular disease
- Potentially persistent pigmentation
- Reduced absorption of some oral medicines
- Pregnancy warning
- One acute hepatitis case with uncertain causality
From labels, regulators and trials. No signal in small studies ≠ safe.
Legal status
US FDAApproved: low desire in women
Approved (acquired generalized HSDD in premenopausal women). Approval concerns the labeled prescription product and indication; not male ED or sexual performance enhancement. Not on the July 23–24, 2026 PCAC agenda; no batch-specific vote applies. Source
checked 2026-11-13WADA 2026Not named
Not listed by name; no applicable prohibition identified for bremelanotide itself. Source
checked 2026-11-13Evidence A low sexual desire in premenopausal women (the approved use)
A stands for that use: FDA approval plus two positive phase 3 RCTs. The approved use is a mainstream marketed use, which is why A survives here and not for tesamorelin. Male libido/erection use is off-label and rests on early intranasal studies; if the page is framed mainly around men, that framing is B at best.
Human trials · 3
- PMID 315998402019Two phase 3 double-blind placebo-controlled RCTs (RECONNECT) 1,267 people
Premenopausal women with HSDD; 1247 treated, 1202 in modified intention-to-treat analysis
Desire and related distress improved; satisfying sexual event count did not significantly improve. Source
- PMID 31599847201952-week open-label extension 684 people
Core-trial completers; 272 completed the extension
Symptom improvements persisted among continuing participants; substantial attrition limits interpretation. Source
- PMID 149634712004Early double-blind placebo-controlled studies size not reported
Healthy men and men with mild-to-moderate ED responsive to sildenafil; sample size not found in accessible abstract
Intranasal doses above 7 mg increased instrument-measured erections; not evidence for current self-injected male regimens. Source
Bar length = trial size on a log scale.
Dose ranges
Reported ranges from labels and studies, with context. Not a recommendation.
- approved label
1.75 mg subcutaneously as needed, at least 45 minutes before activity; at most once per 24 hours; more than 8 doses/month not recommended; discontinue after 8 weeks without improvement Source
Editorial ratings EDITORIAL
Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.
Sources
- pmc.ncbi.nlm.nih.gov/articles/PMC6819021/
- pmc.ncbi.nlm.nih.gov/articles/PMC6819023/
- pubmed.ncbi.nlm.nih.gov/14963471/
- dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=f1d0c1b5-2f39-4bad-a6a4-0066e3ad5dc
- wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
- ema.europa.eu/en/medicines
- pubmed.ncbi.nlm.nih.gov/31599840/
- pubmed.ncbi.nlm.nih.gov/31599847/
- accessdata.fda.gov/drugsatfda_docs/nda/2019/210557Orig1s000MultidisciplineR.pdf
- fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-c
Reddit threads read · 11
- r/pt141info
- r/erectiledysfunction
- r/Peptides
- r/Peptides
- r/Peptides
- r/erectiledysfunction
- r/Peptides_for_Women
- r/pt141info
- r/Biohacking
- r/PSSD
- r/Biohacking
1 further source on commercial or non-primary hosts not listed.
Research checked 2026-11-13.