PT-141
FDA-approved melanocortin receptor agonist · on-demand (SC + intranasal)
PT-141 (bremelanotide) is a ring-shaped peptide that raises sexual desire through the brain, not blood flow. People take it about 45 minutes before sex to lift libido. As Vyleesi, it's FDA-approved for low desire in premenopausal women, backed by Phase 3 trials.
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At a glance
- Dose
- 1,750 mcg (some start at 500–1,000 mcg to gauge nausea)
- Timing
- About 45 minutes before activity
- How
- A small injection under the skin (a nasal route is also used)
- Frequency
- On-demand, max one dose per 24 hours or 8 a month
The 30-second versionEverything on this page, fast
Sexual desire · Works on the brain · On-demand · Libido
The libido peptide that works in the brain, not the bloodstream. PT-141 (Vyleesi / bremelanotide) dials up sexual desire itself through melanocortin signaling. It's taken on-demand, about 45 minutes before.
The basics
- A melanocortin peptide that raises sexual desire by acting on the brain.
- Approved as Vyleesi for low desire in women; widely used on-demand by men too.
Why people use it
- Targets desire itself. Works in the brain, not on genital blood flow like Viagra.
- On-demand, not daily. Taken about 45 minutes before, whenever you want it.
- The only FDA-approved melanocortin for sexual function.
- Complements the "plumbing" drugs. Pairs with Viagra-class drugs (PDE5 inhibitors) for desire plus blood flow.
Stacks well with
- PDE5 inhibitors (the Viagra / Cialis class). PT-141 supplies the desire, they supply the blood flow.
- Otherwise it runs solo, on-demand. Skip Melanotan-2, since it hits the same receptors.
Good to know
- Nausea is the big one (~40% of users), worst on the first dose. A light snack helps.
- It nudges blood pressure up for a few hours, so skip it with uncontrolled hypertension or heart disease.
- Frequent dosing can cause patchy skin or gum darkening, another reason to keep it on-demand.
What it does
PT-141 is the melanocortin people reach for when low desire, not blood flow, is the problem.
- Raises desire itselfIt activates a brain receptor that lifts sexual desire, a different target from drugs that work on blood flow.
- Taken only when you need itOne dose about 45 minutes before activity, not a daily pill.
- FDA-approved for low desireAs Vyleesi, it's the only melanocortin approved for sexual function, backed by Phase 3 human trials.
- Pairs with the plumbing drugsIt covers desire. A PDE5 inhibitor like Viagra covers blood flow.
Sources:DailyMed (Vyleesi)PMID 31599840
How it works
Turns on the brain's receptors. PT-141 activates the melanocortin receptor family, strongest at MC1R and MC4R. At the dose that raises desire, MC4R is the one that matters.
Raises desire, not blood flow. MC4R sits in brain regions that drive sexual motivation. Activating it raises desire, unlike PDE5 inhibitors such as Viagra, which act on genital blood vessels.
Also switches on skin cells. MC1R, PT-141's other main target, drives skin pigmentation, the source of the darkening side effect and the link to melanotan II, the tanning peptide behind PT-141.
Proven in women, studied in men. The Phase 3 evidence covers desire in women. Early human trials in men reported erectile responses.
Sources:DailyMed (Vyleesi)PMID 14963471
How to dose it
PT-141 is taken on-demand, not daily, as a small injection under the skin or a nasal spray.
Dose tiersThe approved dose is 1,750 mcg under the skin. Nasal doses run 500–2,000 mcg.
- Standard, subcutaneous (SC):
- 1.75 mg (1,750 mcg) under the skin, about 45 minutes before activity, the approved Vyleesi dose.
- Intranasal:
- 500–2,000 mcg by nasal spray, the common off-label range for men. Start low.
- First dose:
- Some start at 500–1,000 mcg to gauge nausea before stepping up.
- Frequency cap:
- No more than one dose per 24 hours, or 8 a month.
How to injectThe Vyleesi route, injected under the skin and rotated between doses.
- Injection site:
- Belly, a couple of inches from the navel, or the outer thigh. Rotate to avoid irritation.
- Measuring the dose:
- From a 10 mg vial mixed with 2 mL bacteriostatic water, 1,750 mcg takes 35 units on a U-100 syringe.
- Timing:
- About 45 minutes before activity.
On-demand use and check-inPT-141 is used before an occasion, not daily or in cycles.
- Off-label male dose:
- Reported male doses are similar to the label figure, 1.75 mg SC or 1–2 mg intranasal, on-demand.
- Check-in point:
- The label advises stopping after 8 weeks with no improvement. The same check-in makes sense off-label.
- Why on-demand:
- Daily dosing raises the risk of skin darkening, so on-demand is the safer default.
Mixing the vialA 10 mg vial with 2 mL bacteriostatic water. The calculator handles other sizes.
- Mixing:
- 10 mg vial plus 2 mL bacteriostatic water makes 5,000 mcg/mL. On a U-100 syringe, 500 mcg takes 10 units, 1,000 mcg takes 20 units, 1,750 mcg takes 35 units.
How to spray itThe nasal route people use off-label, measured by spray or drops.
- Technique:
- With a spray, prime it, tilt your head slightly forward and split the dose, one spray per nostril. With drops, half the dose in each nostril, sniffed in gently.
- After dosing:
- Avoid blowing your nose for 10 minutes so the dose has time to absorb.
- Route history:
- It's the earlier-developed route. The male nasal program was stopped, partly over blood-pressure concerns.
Best time to take it
Implied best time
Situational (pre-activity)
People take PT-141 about 45 minutes before activity, whenever that falls, not at a set time each day.
- It's occasion-based. One dose about 45 minutes ahead of activity, then nothing until the next time.
- The 2.7-hour half-life means the effect window sits in the hours right after dosing, so timing beats the clock.
- Spacing doses out is safer too. Daily use raises the risk of skin darkening.
Sources:DailyMed (Vyleesi)
What to stack it with
PT-141 covers desire. A PDE5 drug adds blood flow. Melanotan-2 hits the same receptors, so people skip that pairing.
PT-141 + sildenafil or tadalafilDesire from PT-141, blood flow from a PDE5 drug, two different levers.
- Why it works:
- PT-141 drives desire in the brain. PDE5 drugs open blood vessels in the body. The two don't overlap.
- The real caution:
- PT-141 briefly raises blood pressure. PDE5 drugs lower it. PT-141 is off-limits with uncontrolled high blood pressure or heart disease, and anyone with blood-pressure issues should ask a doctor first.
- The protocol:
- PT-141 1,750 mcg SC or 500–2,000 mcg intranasal, about 45 minutes before. Sildenafil 25–50 mg about 60 minutes before, or tadalafil 5–10 mg earlier in the day.
PT-141 vs. Melanotan-2They hit the same receptors, so people pick one rather than stack them.
- Why they overlap:
- Melanotan-2 hits the same receptors PT-141 does. Running both piles onto one pathway and amplifies the side effects, especially skin darkening and mole changes.
- The safety gap:
- PT-141 is FDA-approved, with Phase 3 safety data out to 52 weeks. Melanotan-2 has neither.
- The verdict:
- Don't stack them. If you want the sexual effect, PT-141 is the better-documented choice.
Support nutrients
PT-141 works through brain dopamine, not blood flow. These cofactors feed that pathway or ease its two main side effects.
Feed the dopamine pathwayL-tyrosine supplies the building block for dopamine, the pathway PT-141 runs through.
- L-tyrosine, 500–1,000 mg:
- Taken about 60 minutes before dosing, on a light stomach, to supply the raw material for dopamine.
- Not the vascular route:
- Arginine and citrulline raise blood flow, the pathway PDE5 drugs use. PT-141 works elsewhere, so they don't feed its mechanism.
Dopamine-pathway cofactorsB6 helps make dopamine. Copper and vitamin C run the next step in the chain.
- Vitamin B6 (P5P), 25–50 mg/day:
- P5P is the active form of B6. The enzyme that turns L-DOPA into dopamine needs it. Take in the morning with food.
- Copper bisglycinate, 1–2 mg/day:
- Feeds the next enzyme in the chain, and balances out any zinc you're also running.
- Vitamin C, 500–1,000 mg/day:
- The reducing cofactor the same enzyme needs.
Ease the blood-pressure rise and nauseaPT-141's two main downsides are a brief blood-pressure rise and nausea. These help with both.
- Skip other stimulants:
- High-dose caffeine and some decongestants add to PT-141's own blood-pressure rise, which peaks 2–4 hours after dosing at about +6 mmHg.
- Magnesium glycinate, 200–400 mg:
- Taken the evening before or morning of dosing, it eases blood pressure and settles the stomach.
- Ease the nausea:
- Roughly 40% of users get nauseous. A light snack, water, 250–500 mg of ginger 30 minutes before dosing, and skipping alcohol around dosing all help.
Dose calculator
Reconstitution calculator
Calculated for a 1 mL U-100 insulin syringe (100 units/mL).
Units per dose
35 units
Draw this many units on a U-100 syringe
Each unit holds 50 mcg
- Volume per dose
- 0.35 mL
- Doses per vial
- 5
- Concentration
- 5 mg/mL
One vial lasts
- Daily
- 5 days
- Every other day
- 11 days
- 5×/week
- 8 days
- Large draw (35 units). That's normal for mg doses. To check it, multiply the units by what each unit holds. You should get your dose.
Research use only. Not for human consumption. Outputs are reference values based on research literature. Verify all measurements independently.
Side effects and what to watch
What people notice. Nausea is the big one, in roughly 40% of users and usually worst on the first dose. After that, flushing shows up in about 20%, injection-site reactions in about 13%, and headache in about 11%.
What to watch for. Each dose briefly raises blood pressure, peaking 2–4 hours after and settling within 12 hours, which is why it's off-limits with uncontrolled high blood pressure or heart disease. About 1% of users get patchy darkening of the skin, face or gums at up to 8 doses a month, more likely with darker skin and with daily use, and it doesn't always fully fade.
Long-term use. A 52-week extension study found no new safety signals.
Sources:DailyMed (Vyleesi)PMID 31599847
Common questions
How is PT-141 dosed?
1,750 mcg under the skin, about 45 minutes before activity. Some start at 500–1,000 mcg on the first dose to gauge nausea. No more than one dose per 24 hours, or 8 a month.
How is it different from Viagra?
Viagra opens blood vessels to help erections. PT-141 raises desire itself by acting on the brain. They solve two different problems.
What's the most common side effect?
Nausea, in about 40% of users, usually worst on the first dose. Flushing, injection-site reactions and headache come next.
Can it darken my skin?
Yes, in about 1% of users at up to 8 doses a month, more likely with darker skin and with daily use. It doesn't always fully fade, which is why it's taken on-demand, not daily.
Can I combine it with Viagra or Cialis?
The mechanisms are complementary, desire plus blood flow. PT-141 briefly raises blood pressure while PDE5 drugs lower it. PT-141 is already off-limits with uncontrolled high blood pressure or heart disease, and anyone else with blood-pressure issues should ask a doctor before combining.
Is it used by men too?
Yes, off-label. Reported doses are similar to the approved figure, about 1.75 mg subcutaneous (SC) or 1–2 mg intranasal, on-demand.
Deep dive
Doses used in studies · Molecular identity · References
10From the researchDoses used in studies
These are the doses used in the published human trials, shown separately from the practical dosing above.
| Dose | Route | Model | Outcome | Sources: |
|---|---|---|---|---|
| 1.75 mg on-demand (24 wk) | SC | Human RCT (RECONNECT Phase 3, premenopausal HSDD, n≈1,247) | Statistically significant improvement vs placebo in desire (FSFI) and distress (FSDS) scores; effect sizes modest, minority reached meaningful response | PMID 31599840 |
| 1.75 mg on-demand (up to 52 wk) | SC | Human open-label extension (RECONNECT completers) | Sustained improvement, no new safety signals; related AEs nausea 40.4%, flushing 20.6%, headache 12.0% | PMID 31599847 |
| 0.75 / 1.25 / 1.75 mg (12 wk) | SC | Human Phase 2b dose-finding (premenopausal women, n≈327) | Established the 1.75 mg dose; pooled 1.25/1.75 mg increased satisfying sexual events vs placebo | DOI 10.2217/whe-2016-0018 |
| Single/early doses | Intranasal | Human Phase 1/2 (men, healthy + Viagra-responsive mild–moderate ED) | Erectile responses (RigiScan) vs placebo; early-phase only; program later halted; NOT approved in men | PMID 14963471 |
11ChemistryMolecular identity
- Molecular weight
- 1025.2 g/mol (free base)
- Molecular formula
- C50H68N14O10
- Monoisotopic mass
- 1024.5243 Da
- CAS / UNII
- 189691-06-3 · 6Y24O4F92S
- Sequence
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH (7 AA, Asp–Lys lactam bridge)PubChem CID 9941379
- Structure / class
- Cyclic α-MSH analog; deamidated metabolite of melanotan II (free-acid C-terminus)PubChem CID 9941379
- Molecular target
- Melanocortin receptor agonist (MC1R > MC4R > MC3R > MC5R > MC2R)FDA Vyleesi label
- Brand / approval
- Vyleesi (bremelanotide), FDA-approved 2019; 1.75 mg SC on-demand for HSDD in premenopausal womenFDA Vyleesi label
- Regulatory status
- FDA-approved for HSDD (premenopausal women) only; male/intranasal use is off-labelFDA Vyleesi label
- Anti-doping status
- Not named on the WADA 2026 Prohibited List (permitted by inference; melanocortin agonist, not S2)WADA 2026
12Primary sourcesReferences
- PubChem CID 9941379PubChem CID 9941379 (Bremelanotide)
- DailyMed (Vyleesi)Vyleesi (bremelanotide) FDA Prescribing Information
- PMID 31599840Kingsberg et al., Obstet Gynecol 2019 (RECONNECT, two Phase 3 trials)
- PMID 31599847Simon et al., Obstet Gynecol 2019 (long-term safety/efficacy)
- PMID 31277966Althof et al., J Sex Med 2019 (Phase 2b responder analyses)
- DOI 10.2217/whe-2016-0018Clayton et al., Womens Health (Lond) 2016 (Phase 2b dose-finding)
- PMID 14963471Diamond et al., Int J Impot Res 2004 (intranasal PT-141 in men)
- WADA 2026WADA 2026 Prohibited List (bremelanotide not named; permitted by inference)
PT-141
10 mg vial
Ki Researcher is affiliated with Ki Peptides.
Ships to the US only. Buyers must be 21 or older.
Reviewed by Ki Researcher Team · Research use only · Not medical advice · Updated 2026-09-24