Short answer: PT-141 is bremelanotide, and bremelanotide is an FDA-approved drug (Vyleesi, 2019). That means its side effects were measured in more than 1,200 women against placebo. The headline number: 40% had nausea, compared with about 1% on placebo. One in five had flushing, one in ten had headaches, and blood pressure rose briefly after each dose. Repeated use can also darken patches of skin and gums. Here is the full picture from the label.
What PT-141 is
PT-141 is a melanocortin receptor agonist derived from the Melanotan II program. Unlike Melanotan II, it was developed for sexual desire rather than tanning, and it acts mainly on the MC4 receptor in the brain. The FDA approved it in June 2019 as Vyleesi, an on-demand injection for premenopausal women with hypoactive sexual desire disorder (HSDD). It is not approved in Canada. For how it compares with related compounds, see kisspeptin vs HCG vs PT-141; for its riskier relative, see Melanotan II side effects.
Side effects vs placebo
Two phase 3, randomized, double-blind trials included 627 women on bremelanotide and 620 on placebo.
| Side effect | Bremelanotide | Placebo |
|---|---|---|
| Nausea | 40.0% | 1.3% |
| Flushing | 20.3% | 0.3% |
| Injection-site reactions | 13.2% | 8.4% |
| Headache | 11.3% | 1.9% |
| Vomiting | 4.8% | 0.2% |
| Cough | 3.3% | 1.3% |
| Fatigue | 3.2% | 0.5% |
| Hot flush | 2.7% | 0.2% |
| Tingling (paresthesia) | 2.6% | 0.0% |
| Dizziness | 2.2% | 0.5% |
The efficacy, for context, was modest: average improvement on the desire score was 0.5 to 0.6 points vs 0.2 on placebo.
Blood pressure and skin darkening
- Blood pressure. Bremelanotide causes a temporary rise in blood pressure and a drop in heart rate after each dose. The label advises against use in people with uncontrolled high blood pressure or known cardiovascular disease.
- Hyperpigmentation. Darkening of the gums, face and breasts was reported, especially with frequent dosing. In the trials, focal hyperpigmentation affected 4% of Black participants vs 1% of white participants, and it did not always resolve after stopping.
Who should avoid it
Per the US label: people with uncontrolled hypertension or cardiovascular disease. It is also not intended for men or postmenopausal women, for whom it is not approved.
| Health Canada | Not approved. PT-141 sold online is an unauthorized drug; bremelanotide was among products seized from Canada Peptide in 2025. |
|---|---|
| FDA (USA) | Approved as Vyleesi (2019) for HSDD in premenopausal women, by prescription. |
See TrueLabs PT-141 and its COA →
Frequently asked questions
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What are the side effects of PT-141?
In phase 3 trials, nausea affected 40% of women vs 1.3% on placebo, flushing 20%, injection-site reactions 13% and headache 11%. It also raises blood pressure briefly after each dose.
Is PT-141 the same as bremelanotide?
Yes. PT-141 is the development code for bremelanotide, sold in the US as Vyleesi.
Does PT-141 raise blood pressure?
Yes, temporarily after each dose, with a decrease in heart rate. It is not recommended for people with uncontrolled hypertension or cardiovascular disease.
Can PT-141 darken your skin?
Yes. Focal darkening of the skin and gums was reported, more often with frequent use and in people with darker skin.
Is PT-141 approved in Canada?
No. It is approved only in the US, as Vyleesi.
Related reading
- What is PT-141 (bremelanotide)?
- Kisspeptin vs HCG vs PT-141
- Melanotan II side effects
- Kisspeptin side effects
References
- US FDA. Drug Trials Snapshots: Vyleesi. FDA
- Health Canada. Advisory RA-77807 (Canada Peptide), August 1, 2025. Recalls and Safety Alerts
All TrueLabs products are sold for in vitro and laboratory research use only. They are not intended for human or veterinary use, and nothing in this article is medical advice.