PT-141: the complete guide

How PT-141 works

PT-141 activates MC3R and MC4R receptors in the hypothalamus, influencing dopaminergic pathways involved in sexual desire in both males and females.

Typical PT-141 dosage

Commonly reported research ranges: 1.75 mg (1750 mcg) per dose on demand, per the Vyleesi label; 0.5–2 mg in other reports.

Label dose: Vyleesi, the FDA-approved form of PT-141 (bremelanotide), is 1.75 mg injected under the skin of the abdomen or thigh, as needed, at least 45 minutes before anticipated sexual activity. The label caps it at one dose in 24 hours and says more than 8 doses a month is not recommended; it should be stopped after 8 weeks if there is no improvement. The approval covers premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD) — the label states it is not indicated for postmenopausal women, for men, or to enhance sexual performance.

Doses studied in men: no dose is approved for men. In a 2004 study, subcutaneous doses from 0.3 to 10 mg were given to healthy men, and the erectile response was statistically significant at doses above 1 mg; men who had an inadequate response to Viagra then received 4 or 6 mg in a crossover design, and both doses produced a significant response (Rosen et al., Int J Impot Res 2004). The label notes that blood levels rise less than proportionally across 0.3–10 mg and peak levels plateau at 7.5 mg, so going above that adds little extra drug in the blood.

What limits the dose: in the phase 3 trials of the 1.75 mg dose, nausea affected 40% of women (13% needed an anti-emetic, 8% stopped), flushing 20% and headache 11%. Each dose raises blood pressure by up to 6/3 mmHg for 2–4 hours, back to baseline within 12 hours. Focal skin darkening was seen in 1% of people using up to 8 doses a month, but in 38% of those dosed daily for 8 days — the label gives this, and the extra time spent with raised blood pressure, as the reasons for the monthly cap.

In syringe units: a 10 mg vial mixed with 2 ml of bacteriostatic water holds 5 mg/ml, so the 1.75 mg label dose is 0.35 ml — 35 units on a U-100 insulin syringe — and the vial holds 5 doses. Vyleesi itself comes as a 1.75 mg/0.3 ml prefilled autoinjector with nothing to mix.

PT-141 dosage chart in units for 1, 2 and 3 ml mixes →

Dose should always be individualized. Factors that influence it include bodyweight, research goal, tolerance, and specific compound batch. The information below is educational, not a prescription.

How to reconstitute PT-141

A widely used reconstitution for a 10 mg vial is 2 ml of bacteriostatic water. With a typical 1750 mcg dose this works out to the unit count shown in the calculator below.

Open the PT-141 reconstitution calculator →

Half-life and administration frequency

Approximately 2.7 hours (range 1.9–4 hours); blood levels peak about 1 hour after a subcutaneous injection.

This half-life informs how often PT-141 is typically dosed. Shorter half-lives usually mean more frequent dosing to maintain plasma levels; longer half-lives allow daily, weekly, or less-frequent administration depending on the compound.

Plot it: the PT-141 half-life and pharmacokinetics chart shows accumulation, steady state, peak and trough for any cadence. Converting between mcg, mg and IU? Use the peptide dose converter.

Reported side effects

• Nausea (40% vs 1.3% on placebo in the Vyleesi phase 3 trials; usually better by the second dose)
• Flushing (20%)
• Injection-site reactions (13% vs 8% on placebo)
• Headache (11%)
• Transient blood pressure rise (up to +6/+3 mmHg, peaking 2–4 hours after a dose) and a slower heart rate
• Focal skin darkening (hyperpigmentation), more likely with frequent dosing

This list reflects effects reported in available literature or user logs. It is not exhaustive. Adverse reactions should be discussed with a qualified clinician.

Common PT-141 stacks

• Typically used alone, on demand

PT-141 compared with

Side-by-side breakdowns against other peptides in the same class or category.

Related peptides

Compounds that come up alongside PT-141 — because they are compared with it, stacked with it, or sit in the same category.

Browse the full peptide glossary, the peptide stack guides, or the reconstitution calculator.

Storage and handling

Lyophilized refrigerated. Reconstituted: refrigerated, use within 28 days.

FDA and regulatory status

FDA approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women.

PT-141 clinical trials and evidence

For clinical-trial and primary-literature context, start with the sources below. We prioritize official drug labels, ClinicalTrials.gov records, and PubMed-indexed literature when available.

• Bremelanotide clinical trial records — ClinicalTrials.gov

Frequently asked questions

References

1. VYLEESI (bremelanotide injection) prescribing information, 2019 — U.S. Food and Drug Administration. 1.75 mg dose, 45-minute lead time, 1 dose per 24 hours, 8 doses per month; adverse-reaction rates; half-life 2.7 hours
2. Rosen RC et al. Evaluation of the safety, pharmacokinetics and pharmacodynamic effects of subcutaneously administered PT-141 in healthy male subjects and in patients with an inadequate response to Viagra. Int J Impot Res 2004;16:135–42 — International Journal of Impotence Research (PubMed). 0.3–10 mg subcutaneous in healthy men (significant erectile response above 1 mg); 4 and 6 mg in men with ED
3. Bremelanotide (Vyleesi, PT-141) — FDA Drugs@FDA — U.S. Food and Drug Administration. FDA approval for hypoactive sexual desire disorder in premenopausal women
4. Bremelanotide pharmacology literature — PubMed. Primary studies on melanocortin agonism and sexual function
5. Bremelanotide clinical trial records — ClinicalTrials.gov. Pivotal and supporting trials

Sources listed above were used to verify the claims on this page. See our editorial policy for how we source information.