PT-141 10 mg vial dosage

What PT-141 is

Class:

Melanocortin receptor agonist

Also called:

Bremelanotide, Vyleesi

Used for:

Approved for premenopausal women with acquired, generalised hypoactive sexual desire disorder. Sold in grey channels predominantly to men.

Human evidence:

Strong human evidence. Two identical Phase 3 randomised, double-blind, placebo-controlled multicentre trials (RECONNECT) in premenopausal women with hypoactive sexual desire disorder, supported by Phase 2b dose-ranging responder analyses and a safety review across the development programme. One older randomised trial exists in men who had not responded to sildenafil; the journal that published it issued a formal Expression of Concern about it in 2023.

US status:

FDA-approved · prescription only. FDA-approved for premenopausal women with acquired, generalised hypoactive sexual desire disorder, at 1.75 mg subcutaneously as needed. Research-chemical vendors sell the molecule name without the approval, quality control or indication.

The full picture, with every study: PT-141 guide.

How to mix a 10 mg PT-141 vial

For this vial: 1 mL of bacteriostatic water makes 10 mg/mL, so 1.75 mg is 17.5 units (0.18 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

1. Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. ^[2][3]
2. With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. ^[2][3][4]
3. Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. ^[5]
4. Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. ^[2][3][5]
5. Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. ^[2]
6. Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. ^[5]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing PT-141 vials

• Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. ^[6]
• Protect peptide vials from heat and light. ^[6][7]
• Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. ^[5][6]
• Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. ^[8][9]

More detail: peptide storage and shelf life.

Injecting safely

• Clean the injection site with an alcohol swab and let the skin dry completely before injecting. ^[10][11]
• Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. ^[10][11][12]
• Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. ^[10]
• Inject slowly, at roughly 10 seconds per mL. ^[10]
• Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. ^[5][10][11]

Hygiene and warning signs

• Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. ^[4][8][11]
• Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. ^[4][7][8]
• Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. ^[13][14]
• Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. ^[11]

Where to inject: subcutaneous injection sites.

How PT-141 works

• PT-141 (bremelanotide, sold as Vyleesi) is a synthetic cyclic peptide of seven amino acids that activates melanocortin receptors. It is a variation of melanotan II designed specifically for sexual stimulation. ^[1][15]
• It is not selective: it activates several melanocortin receptor subtypes, most strongly MC1R and then MC4R. At therapeutic doses these two matter most. MC4R is found on nerve cells in many parts of the brain and spinal cord. ^[1]
• The label states that how it improves low sexual desire in women is unknown. MC1R sits on the skin's pigment cells, and activating it increases melanin and pigmentation. ^[1]

What the PT-141 research found

Human evidence: strong human evidence. Each result says what was studied.

• Human studyIn RECONNECT, two identical 24-week phase 3 randomised trials of 1,267 premenopausal women with hypoactive sexual desire disorder (HSDD), bremelanotide raised sexual desire scores and lowered distress about low desire more than placebo in both trials. ^[16]
• FDA labelThe same trials found no significant difference from placebo in the number of satisfying sexual events, a secondary endpoint. ^[1]
• Human studyPrespecified subgroup analyses of the 1,202 RECONNECT participants found gains in desire and reductions in distress across age, weight, BMI and testosterone groups, with few exceptions. ^[17]
• Human studyResponder analyses of an earlier phase 2b dose-finding trial in premenopausal women found response rates at 1.75 mg were significantly higher than placebo on all 7 endpoints studied. ^[18]
• Human studyA 2008 trial of 342 men with erectile dysfunction who had not responded to sildenafil reported a positive result in 33.5% on intranasal bremelanotide against 8.5% on placebo. The journal issued an expression of concern about this paper in 2023, and this use is not approved. ^[1][19][20]

PT-141 side effects and risks

• FDA labelIn the phase 3 trials, the most common adverse reactions were nausea (40.0% vs 1.3% on placebo), flushing (20.3% vs 0.3%), injection-site reactions (13.2% vs 8.4%), headache (11.3% vs 1.9%) and vomiting (4.8% vs 0.2%). ^[1]
• FDA labelNausea was worst after the first dose (21% of patients) and fell to about 3% after later doses. 13% were given anti-nausea medicine and 8% left the trials because of it. Overall, 18% stopped because of adverse reactions, against 2% on placebo. ^[1]
• FDA labelEach dose briefly raises blood pressure, by up to 6 mmHg systolic and 3 mmHg diastolic at 2 to 4 hours, and lowers heart rate by up to 5 beats per minute. Levels usually return to normal within 12 hours. It is contraindicated in uncontrolled high blood pressure or known cardiovascular disease. ^[1]
• FDA labelFocal skin darkening, including the face, gums and breasts, affected 1% of people taking up to 8 doses a month. In a separate study it affected 38% after 8 daily doses. It was more common in darker skin, and fading after stopping was not confirmed in everyone. ^[1]
• FDA labelBremelanotide can sharply lower blood levels of oral naltrexone, so the label says to avoid it with naltrexone products used for alcohol or opioid dependence. ^[1]
• Human studyA review of the whole development programme (3,500 people in 43 completed studies) reported no deaths, with a few people having serious adverse events. ^[21]

Other things to know

• The modern trial programme and the approval are in premenopausal women. Most grey-market buyers are men, for a different purpose, on the strength of trials not run on them.
• An approved, quality-controlled version exists, which makes an unverified vial a straight downgrade rather than the only option.
• The approved regimen is as needed, not a daily or cycled protocol as vendor pages often describe.

Reported side effects and what the studies measured: PT-141 side effects.

Where this vial size comes from

PT-141 is sold as a 10 mg vial by the pages below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

• BioEdge Research LabsvendorLists it as: "Vial Size: 3 mL sterile vial"; "Fill: 10mg" · checked 2026-09-28
• SwissChemsvendorLists it as: "PT-141 (Bremenalotide), 10mg"; Total Compound Content: 10 mg per vial · checked 2026-09-28

The doses come from the FDA label on the PT-141 dosing page, and every number on this page is arithmetic on those doses and this vial size.

Questions

How much water do I add to a 10 mg PT-141 vial?

There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1 mL the vial is 10 mg/mL and 1.75 mg is 17.5 units (0.18 mL) on a U-100 insulin syringe. The units table gives 1, 2, 5 mL.

How many doses are in a 10 mg PT-141 vial?

5 doses at 1.75 mg.

What does 1 unit equal in a 10 mg PT-141 vial?

100 mcg with 1 mL, 50 mcg with 2 mL, 20 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.