Peptides PT-141 (bremelanotide) is an FDA-approved melanocortin agonist for low libido in premenopausal women. Learn dosage, side effects, and safety.
PT-141 is bremelanotide, a synthetic peptide that the FDA approved in 2019 under the brand name Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. It acts on melanocortin receptors in the brain rather than on blood flow, which is why it is described as a desire drug rather than an erection drug. PT-141 is not approved for men, for postmenopausal women, or for recreational use.
What Is PT-141 (Bremelanotide)?
PT-141 is a cyclic heptapeptide modeled on alpha-melanocyte-stimulating hormone. Researchers originally studied it as a tanning agent and noticed that trial participants reported higher sexual desire, an observation that shifted its development toward sexual medicine.
Bremelanotide is the generic name, and PT-141 was the early research code. Most pt 141 peptides sold online are labeled as research chemicals, which is a completely different product category from FDA-approved prescription medicine.
- Drug class: melanocortin receptor agonist
- Primary target: MC4R in the central nervous system
- Approved brand: Vyleesi (subcutaneous auto-injector)
- Approved dose: 1.75 mg per injection
How Does PT-141 Work?
Bremelanotide binds melanocortin receptors, mainly MC4R, in the hypothalamus and limbic system. That activation is thought to influence dopamine signaling tied to desire and reward, which is why the drug affects libido rather than blood flow.
After a subcutaneous injection, peak blood levels appear in roughly 30 to 60 minutes, and the half-life is about 2.7 hours. Patients are generally advised to dose about 45 minutes before anticipated sexual activity.
Approved Use vs. Off-Label and Gray-Market Use
PT-141 has exactly one FDA-approved indication and several unapproved uses. A pt-141 nasal spray was studied in earlier trials, but that program was discontinued after blood-pressure signals, and no nasal product is FDA approved today.
The table below shows how the same molecule differs by route and regulatory status.
| Form | Regulatory status | What to know |
|---|---|---|
| Vyleesi auto-injector (subcutaneous) | FDA approved in 2019 | Prescription for premenopausal women with acquired, generalized HSDD |
| Intranasal bremelanotide | Not approved | Development halted over transient blood-pressure increases |
| Injectable bremelanotide for men | Not approved | Small studies only; no FDA-reviewed dose or safety profile |
| Compounded or research-grade peptide | Not approved | Purity, sterility, and actual content vary widely |
PT-141 Dosage and Timing
The FDA-labeled pt-141 dosage is 1.75 mg injected subcutaneously into the abdomen or thigh, at least 45 minutes before anticipated sexual activity. Only one dose is allowed in a 24-hour period, and the label caps use at eight doses per month.
Dosing is not weight-based. Higher doses do not produce a stronger effect, and in clinical trials they produced more nausea instead.
Dosing in women
The approved dose is 1.75 mg per injection for premenopausal women with acquired, generalized HSDD, regardless of body weight or age. The drug is used on demand, not as a daily medication.
Use in men
There is no FDA-approved pt-141 for men. Some small studies and clinic reports describe improvements in desire and erectile function, but the evidence is much thinner than it is for women, and clinicians who prescribe it off-label set their own protocols.
Side Effects and Safety
Nausea is the most common side effect, reported by roughly 40% of participants in clinical trials. Flushing, headache, vomiting, injection-site reactions, and short-lived increases in blood pressure and heart rate are also common.
Repeated use can cause focal hyperpigmentation, including darkening of the gums, face, or breasts. Because of the cardiovascular effects, PT-141 is not appropriate for every patient.
Vyleesi is contraindicated in women with uncontrolled hypertension or known cardiovascular disease.
Tell a clinician about blood pressure medications, any history of cardiovascular disease, or pregnancy plans before using bremelanotide. PT-141 has not been studied in pregnancy and is not recommended during breastfeeding.
Buying Research Peptides: What to Watch For
Many people search for research-grade peptides online, where products carry a “not for human consumption” label. Independent testing has repeatedly found that peptides sold this way can be underdosed, mislabeled, or contaminated with bacteria or other compounds.
Buyers comparing suppliers such as paradigm peptides pt 141 should ask for a third-party certificate of analysis covering purity (HPLC), mass identity, and sterility. Even a complete certificate does not make a research peptide safe or legal to inject.
The Bottom Line
- PT-141 (bremelanotide) is an FDA-approved prescription drug for one narrow indication: acquired, generalized HSDD in premenopausal women.
- The approved dose is 1.75 mg subcutaneously, no more than once every 24 hours and no more than eight times per month.
- PT-141 is not approved for men, for nasal use, or for general libido enhancement.
- Nausea, flushing, headache, and blood-pressure changes are common, and cardiovascular contraindications matter.
- Anyone considering PT-141 should talk with a licensed healthcare professional rather than self-sourcing research peptides.
Frequently Asked Questions
Is PT-141 FDA-approved?
Yes, but only in one form and for one group. Bremelanotide is approved as Vyleesi, a 1.75 mg subcutaneous auto-injector, for premenopausal women with acquired, generalized hypoactive sexual desire disorder. It is not approved for men, for nasal use, or as a general libido enhancer.
How long does PT-141 take to work?
Bremelanotide is typically injected about 45 minutes before anticipated sexual activity, and blood levels peak within roughly 30 to 60 minutes. The effect is not automatic and is intended to support desire when sexual activity follows. The half-life is about 2.7 hours.
Does PT-141 work for men?
There is no FDA-approved version of PT-141 for men. Some small studies suggest it may help with desire and erectile function, and some clinicians prescribe it off-label. Because dosing and safety in men are not established by regulators, anyone considering it should consult a healthcare professional.
This page provides educational research information and does not replace medical advice, diagnosis, or treatment.