PT-141, known generically as bremelanotide, is a synthetic cyclic peptide that activates melanocortin receptors in the brain — primarily MC4R, and also MC1R. It is the active ingredient in the FDA-approved prescription drug Vyleesi. It is studied and used for its effect on sexual desire rather than for muscle, recovery, or anti-aging.

Is PT-141 FDA-approved?

Yes — the molecule is FDA-approved. Bremelanotide was approved in 2019 under the brand name Vyleesi (bremelanotide injection) for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD). Importantly, that approval applies to the specific Vyleesi product, not to vials of 'research-only' PT-141 sold online, which are not the approved medicine and have not been evaluated for safety, purity, or potency.

How does PT-141 work?

Unlike erectile-dysfunction drugs that act on blood vessels, PT-141 works centrally in the brain. It is a melanocortin receptor agonist that activates MC4R (and other melanocortin receptors), pathways linked to sexual motivation and arousal. The exact mechanism by which it improves sexual desire is not fully understood, and it does not work primarily through the vascular system.

What is PT-141 studied for?

Its main, FDA-approved use is low sexual desire (HSDD) in premenopausal women. It has also been studied historically for sexual dysfunction more broadly, including in men, but the approved indication is the HSDD use in premenopausal women. Other uses are investigational and not approved.

What are the common side effects?

In the trials behind Vyleesi, the most common adverse reactions were nausea (about 40%, often with the first dose), flushing (about 20%), headache, injection-site reactions, and vomiting. It can cause a transient rise in blood pressure and a drop in heart rate after dosing, and a small percentage of users reported focal skin darkening (hyperpigmentation). Discuss your individual risks with a clinician.

What is PT-141's half-life?

After subcutaneous injection, bremelanotide is absorbed quickly and has a reported terminal half-life of roughly 2.7 hours in humans (range about 1.9–4.0 hours), which is part of why the approved product is used on an as-needed basis rather than daily.

Does WikiPeps provide a PT-141 dose?

No. Even though an approved product exists, WikiPeps does not publish dosing protocols or amounts for any peptide. The approved drug carries specific labeling, warnings, and a limit on how often it can be used — those are medical decisions for a licensed clinician, not something to copy from a website using unregulated material.

Sex drive · Dosage

PT-141 dosage

PT-141 comes in 5 mg and 10 mg vials. Pick your vial to see exactly how much bacteriostatic water to add and how many insulin units to draw. PT-141 is the prescription drug Vyleesi (bremelanotide); its FDA label dose is 1.75 mg subcutaneous, as needed, max 1/24 h and 8/month. Reconstitution math is shown for the 5 mg and 10 mg research vials.

5mg

At 1 mL water: 5 mg/mL
Per unit: 50 mcg

See the 5 mg card

10mg

At 1 mL water: 10 mg/mL
Per unit: 100 mcg

See the 10 mg card

Calculate for your vial

Enter the mg on your PT-141 vial, the bacteriostatic water you added, and your target dose — it works out the exact units to draw on a U-100 insulin syringe, for whatever you personally have.

Reconstitution Calculator

Units to draw (U-100)30units

Volume to draw0.3mL

Concentration5mg/mL

Per insulin unit50mcg

Doses per vial3.3doses

Check the decimal. A misplaced decimal point here is a 10× dosing error. Re-read every number, and confirm your dose with a licensed clinician before you draw.

Educational only — not a dosing recommendation. This tool does the measurement math; it does not tell you what to take. On a U-100 insulin syringe, 100 units = 1 mL.

Reconstitution figures are deterministic measurement math. WikiPeps is a community reference and sells injection supplies only — never peptides. Nothing here is medical advice.