PT-141
Also known as Bremelanotide, Vyleesi, Bremelanotide acetate
PT-141 is a melanocortin receptor agonist that increases sexual desire and arousal by acting in the brain rather than on blood vessels. It is approved as Vyleesi for low sexual desire in premenopausal women and is widely used off-label by men and women for libido and erectile support.
Reviewed by the amino101 editorial team. , first published .
Quick start
What people commonly do. Not a prescription.- Typical dose
- 0.5 to 2 mg per dose (the approved dose is 1.75 mg)
- How often
- as needed, no more than once per 24 hours and 8 doses per month
- Where
- Subcutaneous, belly or thigh; intranasal is an older, less predictable alternative
- Timing
- 45 minutes to 2 hours before sexual activity, on a light stomach
- Effects timeline
- desire and arousal within 1 to 2 hours, peak a few hours in, can persist into the next day
- Storage
- fridge 2 to 8 C once mixed, use within 4 weeks; lyophilized in fridge or freezer away from light
- Cycle length
- not cycled, used per occasion
- Break between
- at least 24 hours between doses
Overview
PT-141, generic name bremelanotide, is a cyclic seven amino acid peptide derived from melanotan-2. During early trials of melanotan-2 as a tanning agent, male participants reported spontaneous erections, and researchers isolated the metabolite responsible. Palatin Technologies developed it first as an erectile dysfunction treatment, initially as a nasal spray, then shifted to an autoinjector for women after the nasal formulation caused blood pressure concerns. The FDA approved it in 2019 as Vyleesi for premenopausal women with hypoactive sexual desire disorder, making it one of the few approved peptides for a sexual indication.
The approval trials enrolled over 1,200 women. Bremelanotide 1.75 mg injected as needed before sexual activity produced statistically significant improvements in desire scores and reductions in distress compared to placebo, though the absolute effect was modest, and about 40 percent of participants had nausea after injection. Earlier trials in men with erectile dysfunction showed improved erections, including in men who did not respond to sildenafil, and the drug remains used off-label for that purpose even though it was never approved for men.
What makes PT-141 different from PDE5 inhibitors like sildenafil is the target. Sildenafil works on blood flow to the penis and does nothing for desire. PT-141 works on melanocortin receptors in the hypothalamus and increases the drive itself, in both sexes, with erection in men as a downstream effect. The trade-offs are nausea, flushing, and a small but consistent rise in blood pressure that lasts several hours after each dose, which is why the label limits use to one dose per day and eight per month and excludes people with uncontrolled hypertension or cardiovascular disease.
How it works
PT-141 is an agonist at melanocortin receptors, primarily MC4R and MC3R, in the hypothalamus and other brain regions involved in sexual behavior. MC4R activation in the paraventricular nucleus and medial preoptic area increases dopamine release in pathways that govern sexual motivation, which is why it raises desire rather than just physical response. In men, the same central signaling triggers erections through spinal pathways to the penis, independent of nitric oxide, which explains why it works in some sildenafil non-responders. The blood pressure increase comes from melanocortin effects on sympathetic tone. Unlike melanotan-2, PT-141 has weak activity at MC1R, so it causes little pigmentation at normal doses.
Where the research stands
Low sexual desire in womenStrong evidence
- Hypoactive sexual desire disorder, premenopausal. Two Phase 3 RCTs (RECONNECT) showed improved desire scores and less distress versus placebo; the effect size was modest.
- Postmenopausal women. Earlier smaller trials showed similar signals, but this group is not in the approved label.
Erectile dysfunctionModerate evidence
- Psychogenic and mixed ED. Intranasal RCTs in men showed improved erections; the nasal formulation was dropped over blood pressure concerns, not lack of effect.
- Sildenafil non-responders. A subset of trial participants who did not respond to sildenafil responded to bremelanotide, since the pathway is central rather than vascular.
Libido in menEmerging
- General desire and arousal. Mechanism and rodent data support it, and community reports are consistent, but no controlled trial has measured desire as a primary outcome in men.
- human RCTBremelanotide 1.75 mg as needed improved sexual desire and reduced related distress versus placebo in premenopausal women with HSDD across two Phase 3 trials.
- human RCTNausea occurred in about 40 percent of women on bremelanotide, leading to discontinuation in around 8 percent.
- human RCTIntranasal bremelanotide produced erections in men with erectile dysfunction, including some who did not respond to sildenafil.
- human RCTBremelanotide caused transient increases in blood pressure of about 6 mmHg systolic and 3 mmHg diastolic lasting up to 12 hours.
- rodentMelanocortin agonists increase sexual motivation and erection in rodents through central MC4R and dopamine signaling.
Rodent and in vitro mean no human data for that finding. Human pilot means small, often uncontrolled. Human RCT means randomized and controlled. Clinical means an approved drug with regulatory data.
Levels over time
Modeled from the half-life. Illustrative, not measured.A half-life of 2.7 h against dosing every 24 h means each dose has cleared before the next. Nothing stacks; you start from zero every time, and the tissue effect is what carries over.
The half-life is long enough that one dose before activity covers the evening, and the once per 24 hours limit exists because the blood pressure rise lasts up to 12 hours.
PT-141 dosage and protocols
Not cycled. It is an as-needed compound, dosed per occasion, with the label cap of one dose per 24 hours and eight per month. Most people start low and step up until they find the dose that gives the effect without much nausea.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| First doses, nausea check | 0.5 mg | as needed | Subcutaneous |
| Approved use in women | 1.75 mg | as needed, max once per 24 hours | Subcutaneous |
| Men, off-label libido or ED | 1 to 2 mg | as needed, max once per 24 hours | Subcutaneous |
| Nausea-prone, second attempt | 0.75 to 1 mg | as needed | Subcutaneous |
Inject 45 minutes to 2 hours before activity on a light stomach and skip alcohol around the dose. Keep it away from stimulants on the same day because both push blood pressure up.
approved dose is 1.75 mg; many people start at 0.5-1 mg to gauge nausea
Dose calculator
U-100 insulin syringeUnits are a volume on the syringe, not an amount of peptide. Concentration changes every time you change the water volume. The standalone calculator explains the math.
| Vial | Suggested water | Concentration | Low dose draw |
|---|---|---|---|
| 10 mg | 2 mL | 5 mg/mL | 10 units |
How to reconstitute PT-141
- 1
Wash your hands and wipe the work surface. Swab both vial stoppers with alcohol and let them dry.
- 2
Pick the water volume with the calculator above and write it on the vial. The concentration means nothing without it.
- 3
Draw the bacteriostatic water into a mixing syringe.
- 4
Insert at an angle and let the water run down the inside wall. Never squirt it straight onto the powder.
- 5
Swirl gently or leave it to dissolve. Do not shake.
- 6
Label with the date and water volume. Store in the fridge at 2 to 8 C and use within about 4 weeks.
- 7
Unmixed vials keep for months in the fridge and longer in the freezer, sealed and out of light.
- Full walkthrough with syringe reading and site rotation: reconstitution guide.
- ✓White, fluffy cake
Lyophilized powder should look like a small white puck or fluffy cake at the bottom of the vial. That is a proper freeze-dry.
- ✓Clear after mixing
Once dissolved the solution should be water-clear with nothing floating in it.
- !Slight clumping
Small clumps that dissolve with gentle swirling are fine. Shipping compacts powder.
- ✕Collapsed or melted
Powder stuck to the sides, glassy, or shrunken means it got hot in transit. Contact the vendor.
- ✕Cloudy or particles
Persistent cloudiness or visible particles after mixing means degraded or contaminated product. Do not use it.
- First 1 to 2 hours
Flushing and nausea often show up before anything else, especially at the full dose; desire starts to rise toward the end of this window.
- Hours 2 to 8
Peak effect on desire and arousal, and erections in men; blood pressure is a few points higher through this period.
- Next 24 hours
Increased desire can carry into the next day for some people; blood pressure returns to baseline within about 12 hours.
- Over repeated use
Nausea usually fades after the first few doses; skin, gum, or mole darkening can appear with frequent use.
Interactions and stacking
Kisspeptin-10synergistic
Kisspeptin adds a hormonal and limbic desire signal on top of the melanocortin pathway; combined human data does not exist.
Melanotan-2caution
Same MC4R activity, so the sexual effects, nausea, and blood pressure rise stack with no added benefit.
PDE5 inhibitors (sildenafil, tadalafil)caution
Commonly combined and they work through different pathways, but watch blood pressure, flushing, and headache.
Stimulants (amphetamines, high dose caffeine, pre-workouts)avoid
Additive blood pressure and heart rate increases on top of a rise that already lasts up to 12 hours.
Uncontrolled hypertension or cardiovascular diseaseavoid
The label excludes these groups because of the sustained blood pressure increase after each dose.
Oral naltrexone and other oral drugscaution
Bremelanotide slows gastric emptying and reduced naltrexone absorption in a drug interaction study; separate dosing where it matters.
Alcoholcaution
Worsens nausea and flushing and does nothing for the effect.
Safety
- ▲Nausea, in roughly 40 percent of trial participants, worst at the full dose and the first few uses
- ▲Flushing and facial redness
- ▲Headache
- ▲Injection site reactions
- ▲Blood pressure rise of about 6 mmHg systolic lasting up to 12 hours
- ▲Darkening of skin, gums, or moles with repeated use
- ▲Raises blood pressure for up to 12 hours after each dose; do not use with uncontrolled hypertension or cardiovascular disease, and avoid combining with stimulants.
- ▲Nausea is very common, especially at the full dose and the first few uses; it usually improves with lower doses.
- ▲Flushing, headache, and injection site reactions are frequent.
- ▲Can cause darkening of skin, gums, and moles with repeated use, particularly in people with darker skin.
- ▲Reduces absorption of oral naltrexone and may lower levels of other oral drugs by slowing gastric emptying.
- ■Blood pressure readings stay elevated or you get headaches with chest symptoms after dosing
- ■Nausea or vomiting is severe or does not ease at lower doses
- ■A mole, patch of skin, or your gums darken noticeably
- ■You are exceeding 8 doses a month or using it daily
Community poll
Self-reported by visitors. Not clinical evidence.PT-141: frequently asked
How is PT-141 different from Viagra?
Sildenafil increases blood flow to the penis and only works if you are already aroused. PT-141 acts in the brain to increase the desire itself and produces erections through a separate nerve pathway. It works in both sexes, it can work in men who do not respond to sildenafil, and it can be combined with PDE5 inhibitors, though that raises the blood pressure question.
How long does it take to work and how long does it last?
Most people notice effects within 45 minutes to 2 hours, with the peak a few hours in. Increased desire can persist for the rest of the day and sometimes into the next, which some people find welcome and others find inconvenient.
How do I deal with the nausea?
Start with a lower dose, around 0.5 to 1 mg, inject on a light stomach rather than empty or full, and avoid alcohol. Nausea tends to be worst the first few times and fades with repeated use. Ondansetron helps if it is severe. Some people find the nasal route gentler.
Is the blood pressure increase dangerous?
For a healthy person, a 6 mmHg bump for several hours is not a problem. For someone with hypertension, heart disease, or who is combining it with stimulants or a PDE5 inhibitor, it can be. The label limits use to once a day and eight times a month for that reason.
References
- Bremelanotide for the treatment of hypoactive sexual desire disorder in premenopausal women: two randomized Phase 3 trials (RECONNECT). Obstetrics and Gynecology, 2019
- Efficacy and safety of intranasal bremelanotide in men with erectile dysfunction. Journal of Urology, 2004
- Vyleesi (bremelanotide injection) prescribing information. US Food and Drug Administration, 2019
- Melanocortin receptor agonists and sexual function: mechanisms and clinical potential. Pharmacology and Therapeutics, 2007