PT-141

Sexual health

Also known as: Bremelanotide, Vyleesi, PT141

A melanocortin agonist that acts in the brain to raise sexual desire. Approved as Vyleesi for low desire in premenopausal women.

Safety:Approved for one use in women, low sexual desire. Use in men is off label. Nausea is very common, and it can raise blood pressure, so it is not for uncontrolled high blood pressure or heart disease.

2.What it is / mechanism

PT-141, also called bremelanotide, is a melanocortin that works in the brain rather than on blood flow. By acting on MC4 receptors it raises sexual desire and arousal. This is different from drugs like sildenafil (Viagra), which mainly improve blood flow. It is a close relative of Melanotan II but is used for desire rather than tanning. It is approved by the FDA as Vyleesi for hypoactive sexual desire disorder in premenopausal women.s1

3.What the evidence supports

Strong human dataRaises sexual desire in premenopausal women with low desire.s1
Approved by the FDA in 2019 based on the phase 3 RECONNECT trials.
Limited human dataHelps libido and erections in men.s2
Used off label in men, with some supporting studies, but this is not an approved use.

4.Dosing

Strong human data

Route(s)	subcutaneous
Typical range	The approved dose is 1.75 mg, taken as needed at least 45 minutes before sex, with no more than 8 doses per month. Doses used in men are often lower.
Frequency	As needed, not daily. No more than 8 times a month.
Cycle guidance	Used on demand, not in cycles.
Notes	Because it is used on demand rather than daily, it does not build up. The limit of 8 doses a month exists because frequent use can cause patchy skin darkening. Take it well before activity, since nausea peaks early.

A dose is only as good as the draw. Which syringe you need depends on how much water you mixed with, and the most common gear mistakes (a 0.5 mL syringe that cannot hold the dose, a mixing barrel that ships without needles, sizing up a needle because of body fat) are all avoidable. See what to buy: syringes, needles, and the rest of the kit.

5.Reconstitution

Vial sizes	10 mg
Diluent	Bacteriostatic water for multi dose vials, or sterile water for single use
Concentration	Example: a 10 mg vial plus 1 mL of water gives 10 mg/mL, so a 1.75 mg dose is 0.175 mL, which is about 18 units on a U-100 syringe.
Notes	The approved product (Vyleesi) is a prefilled autoinjector. Research material is usually a 10 mg freeze dried vial.

Reconstitution calculator

Pick your vial size and how much water you add to see the draw volume and syringe units for a dose. Open the full calculator →

Inputs

Which do you know?

You want a set amount of compound. We show how many units to draw on the syringe.

Reminder: 1 mg = 1,000 mcg

Peptide in vial

Total amount stated on the vial, e.g. 5 mg.

Bacteriostatic water added

How much diluent you draw into the vial.

Desired dose

Check this before you read the result. 1 mg = 1,000 mcg, so picking the wrong one is a 1,000x error, not a rounding error.

Result

Draw to

5 units

= 0.05 mL on a U-100 syringe

Easy draw: this dose comes out to a clean 5 units.

Aim for a dose that lands on an even number of units, like 10, 20, or 50. It is easier to draw accurately and to remember, and it keeps you off awkward repeating decimals.

Concentration: 5,000 mcg/mL
Per unit: 50 mcg / unit
Doses per vial: 40

Your settings live in the address bar, so a pasted link opens this calculator exactly as you left it.

Educational estimate only. Not medical or dosing advice. Verify every calculation independently before use.

General reconstitution technique →

6.Storage & stability

Lyophilized (dry)

Temp	Freeze for long term storage, or 2 to 8 short term
Shelf life	Many months when frozen
Notes	Keep dry and out of light until you mix it.

Reconstituted

Temp	2 to 8 (refrigerated)
Shelf life	About 2 to 4 weeks
Notes	Do not freeze after mixing. Discard if cloudy or discolored.

General storage & stability guide →

7.Reported side effects

WarningTemporary rise in blood pressure and drop in heart rates1Usually mild and short, but it is why heart conditions matter.
WarningPatchy skin darkening with frequent use(uncommon)s1More likely if you go over the monthly dose limit.
CautionNausea(common)s1Very common, about 40 percent on the first dose, and it fades with use. Taking it earlier before activity helps.
CautionFacial flushing(common)s1
CautionHeadache(common)s1

8.Interactions & stacking risks

CautionBlood pressure mediciness1
It transiently raises blood pressure, so discuss timing with your prescriber.
WarningOral naltrexones1
PT-141 can lower naltrexone levels, which matters for anyone using it for alcohol or opioid dependence.
CautionMelanotan II or other melanocortin agonists
They share a mechanism, so combining adds to the nausea and blood pressure effects.

9.Contraindications / who should avoid

SeriousUncontrolled high blood pressure or known heart disease
It can raise blood pressure, so it is not for uncontrolled hypertension or cardiovascular disease.
SeriousPregnancy or breastfeeding
No safety data in pregnancy or breastfeeding.

10.COA & purity notes

Common adulterants	underdosed or mislabeled research vials, research material sold without the controls of the approved product
Mislabeling	There is an approved product (Vyleesi) made to pharmaceutical standards. Research vials are not, so a recent third party COA matters.
Notes	PT-141 has an FDA approved version (Vyleesi) for women. Research or off label material is not the same product.

How to read a COA →

11.Sources

[s1]U.S. FDA / Obstetrics & Gynecology (2019). Bremelanotide (Vyleesi) approval and the RECONNECT phase 3 trials. rct link
[s2]Clinical review (2024). PT-141 (bremelanotide) for sexual dysfunction: clinical overview. review

Last reviewed 2026-07-08 · status: reviewed