PT-141 (10 mg vial) dosage protocol

1. Draw 3 mL of bacteriostatic water with a sterile syringe.
2. Inject it slowly down the inside wall of the vial, not onto the powder, to avoid foaming.
3. Swirl or roll the vial gently until the powder dissolves. Do not shake it.
4. Label it with the date and the volume of water, and refrigerate at 2-8 °C (36-46 °F), away from light.

• Reconstitute: add 3 mL of bacteriostatic water for a 3.33 mg/mL solution.
• Amounts in the chart: 500 mcg-1.5 mg each time, by subcutaneous injection, once a day.
• Easy measuring: at 3.33 mg/mL, one unit (0.01 mL) on a U-100 insulin syringe holds about 33.3 mcg.
• Storage: freeze-dried, keep it sealed, cold and away from light (frozen for long storage). Once mixed, refrigerate at 2-8 °C and avoid freezing and thawing.

PT-141 is the research name for bremelanotide, a synthetic peptide that activates melanocortin receptors in the brain. As Vyleesi, it is FDA-approved for one form of low sexual desire in premenopausal women; products sold as "PT-141" are not that approved drug.

• Primary calculation: 10 mg made up to 3 mL equals 3.33 mg/mL.
• Amounts shown: 500 mcg-1.5 mg per administration. Reported in the research community. It has not been tested as a schedule in human trials.
• Route and frequency: subcutaneous injection, once a day.
• Evidence ceiling: 7 of the 8 studies with a dose in our library were done in people.
• Regulatory status: FDA-approved as Vyleesi (bremelanotide) for one indication. Products sold as "PT-141" for research are not the approved drug.
• Approved drug: the prescription drug has its own dosing in its FDA label. See the label dosing.

A 10 mg vial holds 10,000 mcg of PT-141. Adding 3 mL gives 3.33 mg/mL, so one U-100 unit (0.01 mL) holds 33.3 mcg. To get the units for an amount, divide it by 33.3 mcg. The units are a volume mark on the syringe, not a measure of potency.

• 500 mcg: 0.15 mL, or 15 U-100 units.
• 1 mg: 0.3 mL, or 30 U-100 units.
• 1.5 mg: 0.45 mL, or 45 U-100 units.

Vial coverage by mass: 20 full amounts of 500 mcg, 10 full amounts of 1 mg, 6 full amounts of 1.5 mg per vial, before any handling loss.

If a different volume of water is used, every unit figure changes: recalculate with the calculator above.

Bremelanotide has more human data than most peptides on this site, because it went through a full drug development programme. The main studies:

• Early studies in men: as a nasal spray in healthy men and men with erectile dysfunction, doses above 7 mg produced erections measured by a device, starting about 30 minutes after dosing; flushing and nausea were the most common side effects (Diamond 2004). An injected form produced erections in men who had not responded well to sildenafil (Rosen 2004). It was never approved for men.
• First study in women: in 18 premenopausal women with sexual arousal disorder, a single 20 mg nasal dose increased the number who reported moderate or high desire compared with placebo, but did not change measured genital blood flow (Diamond 2006).
• Phase 2b dose-finding trial: 327 women used 0.75, 1.25 or 1.75 mg injections or placebo as desired for 12 weeks. The two higher doses together increased satisfying sexual events by 0.7 per month versus 0.2 with placebo, and improved desire and distress scores (Clayton 2016).
• Phase 3 trials (RECONNECT): two 24-week trials in 1,267 premenopausal women with HSDD found that 1.75 mg as needed improved desire and reduced distress compared with placebo. These are the basis of the FDA approval (Kingsberg 2019).
• Long-term extension: 684 women continued in a 52-week open-label phase; 272 completed it. No new safety signals were reported, and improvements in desire scores were maintained in those who stayed (Simon 2019).
• Blood pressure study: ambulatory monitoring in 397 women showed small, short-lived rises in blood pressure and falls in heart rate after dosing (White 2017).
• Pooled safety review: across 43 studies and about 3,500 people, nausea, flushing and headache were the most common side effects (Clayton 2022).

Verdict: in premenopausal women with HSDD, bremelanotide produced a statistically clear but modest improvement in desire and distress scores compared with placebo, at the cost of frequent nausea. Most of the evidence comes from the developers, and an independent re-analysis questioned how meaningful the benefit is (Spielmans 2021). There is no comparable evidence for men, for postmenopausal women, or for any other use.

Doses used in human studies

• Kingsberg SA 2019: 1.75 mg as needed before anticipated sexual activity (Subcutaneous autoinjector, as needed; 24 weeks)
• Diamond LE 2004: Range of single intranasal doses; erectile responses were significant at doses above 7 mg. Full dose range not given in the abstract; see the paper (Intranasal, single doses)
• Rosen RC 2004: 0.3 to 10 mg in healthy men; placebo, 4 mg or 6 mg in a crossover design in men with erectile dysfunction (Subcutaneous, single doses)
• Diamond LE 2006: 20 mg single intranasal dose, or placebo, in a double-blind crossover design (Intranasal, single dose; Two in-clinic sessions, with responses recorded over the following 24 hours)
• Clayton AH 2016: 0.75 mg, 1.25 mg or 1.75 mg, or placebo, self-administered as desired (Subcutaneous, self-administered as desired; 12 weeks)
• White WB 2017: 0.75 mg, 1.25 mg or 1.75 mg, or placebo (Subcutaneous)

Every study dose, including animal and cell studies, is in the PT-141 dose table.

Because it is an approved drug, bremelanotide's side effects are better documented than those of most peptides. In the double-blind phase 3 trials, side effects were common and were the main reason people stopped (Clayton 2022). The FDA prescribing information lists uncontrolled high blood pressure and known cardiovascular disease as reasons not to use it.

• Nausea, flushing and headache: nausea affected 40.0% on bremelanotide versus 1.3% on placebo, flushing 20.3% versus 1.3%, and headache 11.3% versus 1.9% (Clayton 2022). An independent analysis found that the odds of dropping out because of side effects were about 12 times higher on the drug than on placebo (Spielmans 2021).
• Blood pressure and heart rate: systolic blood pressure rose by about 2 to 3 mmHg compared with placebo in the hours after a dose, with a fall in heart rate; peaks usually lasted under 15 minutes (White 2017).
• Skin darkening (focal hyperpigmentation): rare at the doses used in the phase 3 trials, but it occurred in more than a third of people given up to 16 daily doses in a row (Clayton 2022). The FDA label notes it can affect the face, gums and breasts, is more likely with darker skin and daily dosing, and did not always resolve.
• Drug interactions: it lowered blood levels of the painkiller indomethacin and of naltrexone, a medicine used for alcohol and opioid dependence (Clayton 2022).
• Product quality: products sold online as "PT-141" are not Vyleesi. No regulator checks their identity, purity, dose or sterility, and none of the trial results above apply to them automatically.
• Sport: we could not find bremelanotide named on the 2026 WADA Prohibited List. That list is not exhaustive, so athletes should check with their anti-doping organisation.

• FDA: FDA-approved as Vyleesi (bremelanotide) for one indication. Products sold as "PT-141" for research are not the approved drug.
• Evidence limits: reported use is not evidence that a schedule works or is safe. Animal doses do not convert to people, and research products are not made or checked for use in people.
• Status checked on: Oct 26, 2026.