PT-141 (bremelanotide, Vyleesi): research, side effects and dosage
In short
PT-141, or bremelanotide, is a peptide acting on melanocortin receptors that is approved in the United States as Vyleesi for low sexual desire in women [4]official. It has no marketing authorisation in the EU [5]regulator.
- In two phase 3 trials in 1,267 women, bremelanotide increased desire and reduced related distress more than placebo [1]A.
- The differences were small, and a later analysis questioned whether the efficacy measures were valid [3].
- The most common harm is nausea, which occurred in 40%. It temporarily raises blood pressure and can darken the skin [4]official.
- The approval covers only premenopausal women, not men and not enhancing sexual performance [4]official.
- In Finland bremelanotide is in Annex 1 of the medicines list, so it is controlled as a medicine [7]regulator, and Fimea warns against injectable peptides bought online [6]regulator.
What is PT-141?
PT-141 is another name for bremelanotide [8]E, not peer-reviewed. Bremelanotide is a peptide that activates several subtypes of melanocortin receptors [4]official.
In the United States it is sold as a prescription medicine under the name Vyleesi [4]official. It is injected under the skin as needed before sexual activity, not daily [1]A [4]official.
A product sold online as "PT-141" is not an authorised medicine [5, 6]regulator. See also: Melanotan II. Basics: What are peptides?. All substances: Peptides A-Z.
Evidence at a glance
Each cell gives the kind of study and its source. The letter is the evidence level, not the result.
| Claimed effect | Humans | Animals | Cells |
|---|---|---|---|
| Sexual desire (premenopausal women) | 2 randomised phase 3 trials, 1,267 women; desire rose more than with placebo, small difference [1]A [3] | - | - |
| Distress about low desire | Fell more than with placebo, by 0.33 points combined [1]A | - | - |
| Long-term use | 52-week open-label extension with no comparison group; 272 of 684 women completed it [2]B | - | - |
| Men or performance | Not an approved indication [4]official | - | - |
| Safety | Nausea in 40%, temporary rise in blood pressure, focal skin darkening [4]official | - | - |
"-" = no such study is known.
What is PT-141 used for?
In the United States PT-141 (bremelanotide) is approved for one indication: acquired, generalised hypoactive sexual desire disorder (HSDD) in premenopausal women [4]official.
- Conditions: low desire causes marked distress and is not due to another condition, relationship problems or a medicine [4]official.
- Not approved: for postmenopausal women, for men or to enhance sexual performance [4]official.
In the EU bremelanotide has no marketing authorisation, and the EMA data contain no application for it [5]regulator.
How does PT-141 work?
How PT-141 works is not known in detail. According to the US label, it is not known how bremelanotide affects sexual desire [4]official.
Bremelanotide activates several melanocortin receptors. At treatment doses MC1R and MC4R are the most relevant, and MC4R receptors are found in many areas of the central nervous system [4]official.
Has PT-141 been studied in humans?
Yes. Bremelanotide has been studied in two randomised phase 3 trials and their open-label extension [1]A [2]B.
The RECONNECT trials
- Design. Two identical trials randomised 1,267 premenopausal women with low sexual desire. They used bremelanotide or placebo as needed for 24 weeks. The mean age was 39 years, and 96.6% came from US study sites [1]A.
- Desire. The desire score (FSFI-desire) rose more with bremelanotide than with placebo: by 0.30 points in the first trial and 0.42 points in the second, 0.35 points combined [1]A.
- Distress. Distress related to low desire fell by 0.33 points more than with placebo in the combined analysis. The differences were statistically significant [1]A.
Extension study and re-analysis
A 52-week open-label extension enrolled 684 women, and 272 completed it. Desire and distress scores stayed better than at baseline. Everyone received bremelanotide, so there was no comparison group [2]B.
An analysis published in 2024 judged that there is little evidence that the efficacy measures used in RECONNECT are valid in women with HSDD. According to its authors, effects on the previously unpublished efficacy outcomes ranged from nil to small, and 8 of the 11 registered efficacy outcomes had gone unpublished [3].
Who studies PT-141?
The PT-141 phase 3 trials were funded by the companies Palatin Technologies and AMAG Pharmaceuticals [1]A [2]B. The 2024 re-analysis was done by Spielmans and Ellefson [3].
Who wrote this page: the editorial team
This page was written by the Molecular Recovery editorial team. The draft was made with the help of AI, and the claims were checked against the sources (AI policy). The page has not been medically reviewed. How we work: About us.
What are the side effects of PT-141?
The most common harms of PT-141 are nausea, flushing and headache. Bremelanotide also temporarily raises blood pressure and can darken the skin [1]A [4]official.
What users report. In the Reddit accounts we compiled (not research), 43 of 59 people (73%) reported some harm, most often: flushing (17, 29%), nausea or vomiting (14, 24%) and fatigue (6, 10%). People tend to post when something goes wrong, so this share does not tell how common harms are. Use was usually one-off: of the 34 people who said how long they had used it, 30 had used PT-141 for under a week. Benefit and harm often went together: 23 people (39%) reported both. The harms in detail: PT-141 user experiences.
Common harms
- In the phase 3 trials, nausea, flushing and headache were more common with bremelanotide than with placebo, 10% or more in both trials [1]A.
- According to the label, nausea occurred in 40%. Anti-nausea medicine was needed by 13%, and 8% left the trials because of nausea [4]official.
- In the extension study, nausea occurred in 40.4%, flushing in 20.6% and headache in 12.0% [2]B.
Blood pressure and heart rate
Bremelanotide temporarily raises blood pressure and slows the heart rate after each dose. Systolic pressure rose by up to 6 mmHg and diastolic by 3 mmHg 2-4 hours after a dose, usually returning to baseline within 12 hours [4]official.
Skin darkening
Focal darkening of the skin (face, gums, breasts) occurred in 1% of those using up to 8 doses a month. In another study, 38% developed darkening after 8 days of daily use. The risk was higher in people with darker skin, and it could not be confirmed that the darkening cleared in everyone after stopping [4]official.
Risks in products bought online
According to Fimea, a product bought online may contain a different substance from the one on the label, and in injectables impurities such as endotoxins can cause serious harm [6]regulator. More: Side effects and safety.
Interactions and who lacks data
According to the label, bremelanotide is not used in uncontrolled high blood pressure or known cardiovascular disease [4]official. There is no approval for men or postmenopausal women, because the approval covers only premenopausal women [4]official.
According to the label, bremelanotide may slow gastric emptying and so the absorption of oral medicines. It should not be used with oral medicines whose effect depends on reaching a threshold concentration (for example antibiotics). It may also markedly lower the exposure of oral naltrexone, so it should not be used with naltrexone taken for alcohol or opioid addiction [4]official.
Data on pregnancy are too few, and animal studies showed fetal harm. The label therefore advises effective contraception and stopping if pregnancy is suspected. It is not known whether bremelanotide passes into breast milk [4]official.
What speaks against it and what is unknown
In the trials the difference from placebo was statistically significant but small, and one re-analysis judged the effects nil to small [1]A [3].
Contrary evidence
- According to the re-analysis, there is little evidence that the efficacy measures are valid in women with HSDD, and 8 of the 11 registered efficacy outcomes had gone unpublished [3].
- In the extension study 272 of 684 women completed it, and there was no comparison group [2]B.
- Nausea was common enough that 8% stopped because of it [4]official.
What the evidence does not support
- "PT-141 improves erections or performance in men": the approval does not cover men or enhancing performance [4]official.
- "The more often, the better": the efficacy of consecutive doses has not been established, and daily use increased skin darkening [4]official.
- "Online PT-141 is the same as Vyleesi": the online product is not an authorised medicine, and its content may differ from the label [6]regulator.
It is not known how long one dose works or what the best timing is, and there are few data on more frequent use [4]official.
PT-141 dosage in studies and in the label
Bremelanotide has an approved dosage in the United States, but no marketing authorisation in the EU [4]official [5]regulator. Below are the dose in the US label and the dose used in studies. They are not advice; the dose is decided by a doctor.
| Study | Who | Dose and route | Duration |
|---|---|---|---|
| Vyleesi, US label | premenopausal women with HSDD | 1.75 mg under the skin as needed, at least 45 minutes before sexual activity; no more than one dose in 24 hours, more than 8 doses a month not recommended | stop after 8 weeks if symptoms have not improved [4]official |
| RECONNECT (2019) | 1,267 premenopausal women | 1.75 mg under the skin as needed | 24 weeks [1]A |
| Extension study (2019) | 684 women | bremelanotide for everyone, open-label | 52 weeks [2]B |
What the numbers do not tell you. The label limits use to one dose in 24 hours because the efficacy of consecutive doses has not been established and the blood pressure effect may add up [4]official. The figures concern the medicine, not powder bought online. More: PT-141 dosage. The calculator does not open with PT-141 preselected, because use of the approved medicine is set out in its product information and by the prescriber. The general calculator's list includes PT-141 only to fill in the vial size of powder sold online; that powder is not the approved medicine Vyleesi.
Situation in the United States
The US Food and Drug Administration (FDA) approved Vyleesi (bremelanotide) on 21 June 2019. It is indicated for acquired, generalised hypoactive sexual desire disorder in premenopausal women [4]official. It is not indicated for postmenopausal women, for men or to enhance sexual performance [4]official.
Is PT-141 legal in Finland?
In Finland bremelanotide is a medicinal substance, but there is no authorised product in the EU [5, 7]regulator.
- Medicines list. Bremelanotide is listed in Annex 1 of Fimea's medicines list (230/2025) [7]regulator. Annex 1 substances are controlled as medicines in Finland, so bremelanotide is not a supplement or a chemical. Dopinglinkki, a Finnish information service on doping, also lists bremelanotide (PT-141) as a substance on the medicines list [8]E, not peer-reviewed.
- Marketing authorisation. The EMA medicines data (as of 15 Sep 2026) list no product or application containing bremelanotide. The data cover medicines evaluated centrally by the EMA [5]regulator.
- Fimea warning, 29 June 2026. Fimea warned about injectable peptides bought online and through social media and sold as "for research use only". According to Fimea, that label means the product is not intended for humans, and medicines should be bought only from legal pharmacies [6]regulator.
- Import. Ordering medicines from outside the EU is covered on Peptides and the law in Finland. Bringing them back from travel: Travelling with peptides.
This is not legal advice. Disclaimer.
How is a PT-141 product assessed?
A product sold online as "PT-141" is not an authorised medicine, and its manufacture is not supervised like a medicine's [5, 6]regulator. According to Fimea, such a product may contain a different substance from the one on the label [6]regulator.
A seller's own certificate of analysis (COA) does not by itself prove purity or content, and it does not show that the product is safe. "For research use only" means the product is not intended for humans [6]regulator. More: How to read a COA and check a test result.
FAQ
What is PT-141?
It is bremelanotide, a peptide acting on melanocortin receptors [4]official [8]E, not peer-reviewed. In the United States it is sold as a medicine under the name Vyleesi [4]official.
Is PT-141 legal in Finland?
Bremelanotide is in Annex 1 of the Finnish medicines list, so it is controlled as a medicine [7]regulator, and there is no authorised product in the EU [5]regulator. Fimea warns against buying injectable peptides online [6]regulator. This is not legal advice.
Does PT-141 work according to studies?
Partly. In phase 3 trials desire increased and distress fell more than with placebo, but the differences were small [1]A, and a re-analysis questioned the measures [3].
Is PT-141 approved for men?
No. The US approval covers only premenopausal women, and it is not indicated to enhance sexual performance [4]official.
Is PT-141 safe?
It has common harms. Nausea occurred in 40%, and it temporarily raises blood pressure and can darken the skin. It is not used in uncontrolled high blood pressure or cardiovascular disease [4]official.
How often can PT-141 be taken?
The US label limits use to no more than one dose in 24 hours, and more than 8 doses a month is not recommended [4]official. This is not dosing guidance: dosage in studies.
Who gives dosing instructions?
There is no authorised bremelanotide product in Finland, so there is no Finnish package leaflet [5]regulator. In the US a doctor prescribes it according to the Vyleesi label. This page only states what studies and the US label have used [1]A [4]official.
What do users themselves report about PT-141?
In the Reddit accounts of 59 people we compiled (not research), 35 (59%) reported some benefit and 43 (73%) some harm. The accounts are self-selected and prove neither that it works nor that it is safe: PT-141 user experiences.
Read the research yourself: sources
Every source opens the original publication or the regulator's page. The level shows what the source itself reports.
- Kingsberg SA, et al. Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials. Obstet Gynecol. 2019;134:899-908. PMID 31599840 A
- Simon JA, et al. Long-Term Safety and Efficacy of Bremelanotide for Hypoactive Sexual Desire Disorder. Obstet Gynecol. 2019;134:909-917. PMID 31599847 B
- Spielmans GI, Ellefson EM. Small Effects, Questionable Outcomes: Bremelanotide for Hypoactive Sexual Desire Disorder. J Sex Res. 2024;61:540-561. PMID 36809187 (review)
- U.S. Food and Drug Administration. Drugs@FDA: NDA 210557 Vyleesi (bremelanotide), approval 21 Jun 2019, prescribing information (revised 6/2019). FDA official
- European Medicines Agency. Medicine data (data set of 15 Sep 2026): no entry for bremelanotide. EMA regulator
- Fimea. Fimea varoittaa: älä käytä verkosta ostettuja pistettäviä peptidejä / Fimea warns: do not use injectable peptides purchased online. 29 Jun 2026. Fimea regulator
- Finland. Lääkeluettelo (Fimea medicines list), 230/2025, annex 1. Finlex regulator
- Dopinglinkki. Mitä peptidit ovat? Dopinglinkki E, not peer-reviewed
Research sources checked 9 Oct 2026. Regulator and registry sources checked 15 Sep to 13 Oct 2026.
Evidence levels: A = randomised human trial or meta-analysis · B = observational human study or case series · C = animal study · D = cell or laboratory study · E = not peer-reviewed · regulator = a regulator's assessment or decision, not research evidence. The marker official means official product information (summary of product characteristics or label); it is not research evidence. For a review, the level shows what kind of research the statement rests on. No level: statements that something has not been studied, reviews' interpretations, named hypotheses and the general rules in our certificate-of-analysis guide.
Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.