PT-141 vs Melanotan II
The libido peptide was discovered inside the tanning peptide. Which one do you want?
Reviewed by the amino101 editorial team. , first published .
PT-141 and Melanotan II are more closely related than any other pair on this site. Melanotan II is a cyclic seven amino acid analog of alpha-MSH built for tanning that activates four melanocortin receptors at once. In early trials, male volunteers reported spontaneous erections, researchers isolated the metabolite responsible, and that became PT-141, bremelanotide. PT-141 acts mainly on MC4R and MC3R in the brain, which drive sexual motivation, and has weak activity at MC1R, the skin receptor, so it causes little pigmentation. The FDA approved it in 2019 as Vyleesi for hypoactive sexual desire disorder in premenopausal women; it is used off label by men. Melanotan II was never approved, and regulators in the UK, Australia and parts of the EU have warned against it. One is an approved drug with a defined dose; the other is a grey market product that does several things at once, with nausea and mole darkening as the cost. This is an educational comparison.
| PT-141 | Melanotan-2 | |
|---|---|---|
| Typical dosage | 0.5 to 2 mg per dose (the approved dose is 1.75 mg) | 0.25 to 1 mg |
| Frequency | as needed, no more than once per 24 hours and 8 doses per month | daily during loading, then 1 to 2 times weekly |
| Route | Subcutaneous, Intranasal | Subcutaneous, Intranasal |
| Half-life | about 2.7 hours | about 1 hour |
| Cycle | not cycled, used per occasion | 2 to 3 week loading phase, then maintenance as desired |
| Research level | Extensively studied | Limited research |
| Human trials | Approved drug | Small pilots |
| Status | FDA approved (Vyleesi) for hypoactive sexual desire disorder in premenopausal women; off-label in men | Investigational, not FDA approved; regulators in several countries have issued warnings against its sale |
| Effects timeline | desire and arousal within 1 to 2 hours, peak a few hours in, can persist into the next day | nausea and flushing within an hour of the first doses, visible darkening within 1 to 2 weeks, full tan in 2 to 3 weeks |
Key differences
PT-141 vs Melanotan-2 dosage
Dosage patterns reported in research and community protocols, by goal. Taken from each compound page. Not a prescription.
| Goal | Dosage | Frequency |
|---|---|---|
| First doses, nausea check | 0.5 mg | as needed |
| Approved use in women | 1.75 mg | as needed, max once per 24 hours |
| Men, off-label libido or ED | 1 to 2 mg | as needed, max once per 24 hours |
| Nausea-prone, second attempt | 0.75 to 1 mg | as needed |
| Goal | Dosage | Frequency |
|---|---|---|
| Nausea test, first days | 0.25 mg | once daily |
| Loading, typical | 0.5 mg | once daily |
| Loading, high tolerance | 1 mg | once daily |
| Maintenance | 0.5 to 1 mg | 1 to 2 times weekly |
Convert any of these to syringe units in the dosage calculator.
Side effects compared
- ▲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
- ▲Nausea and sometimes vomiting, nearly universal for the first several doses
- ▲Flushing and facial redness
- ▲Darkening of moles and freckles, and new moles appearing
- ▲Spontaneous erections and increased libido
- ▲Reduced appetite
Which should you choose?
PT-141 is the fit for anyone whose goal is sexual desire or erectile support and nothing else. It is an approved drug with a defined dose, 1.75 mg in women, with 0.5 to 1 mg as the commonly reported starting point to gauge nausea. It works centrally, so it helps some people PDE5 inhibitors do not. Skip it with uncontrolled blood pressure or heart disease.
Melanotan II is the fit for someone who wants a fast, deep tan and accepts nausea, mole darkening and the libido and appetite effects as part of the deal. Protocols start at 0.25 mg in the evening and hold there until the nausea fades. Get a skin check before and after a cycle, and consider Melanotan I for maintenance.
Pick by what you want. If the goal is libido or erectile support, PT-141 is the answer: it was designed for exactly that, it has phase 3 trials and an approval, and it does not tan you. Men using it off label report it works through desire rather than blood flow, which is why it helps some sildenafil non responders. If the goal is a tan, Melanotan II will do it faster than anything else, and the libido and appetite effects come along whether you want them or not. The worst reason to choose Melanotan II is to get both effects from one vial, because the receptor promiscuity that makes it do everything is also what makes it darken moles and cause the nausea people complain about. For a tan with fewer surprises, see Melanotan I vs Melanotan II. For either compound, the blood pressure rise means no stimulants on the same day and no use with uncontrolled hypertension.
Stacking: Rarely combined; PT-141 already covers the sexual effect of Melanotan II. People wanting both tan and libido usually just use MT-II, accepting the side effects.
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.
Melanotan-2 is a cyclic alpha-MSH analog that darkens skin quickly and also boosts libido and suppresses appetite because it hits several melanocortin receptors at once. It is the most widely used tanning peptide and the one with the most side effects.
PT-141 vs Melanotan II: frequently asked
Is PT-141 the same as Melanotan 2?
No, but it came from it. PT-141 is a metabolite of Melanotan II that researchers isolated after trial participants reported erections. PT-141 is selective for the brain receptors that drive sexual motivation; Melanotan II also hits the skin receptor and others, which is why it tans and PT-141 mostly does not.
Does Melanotan 2 increase libido like PT-141?
Yes, through the same MC4R pathway, which is how PT-141 was discovered. The difference is that Melanotan II brings tanning, appetite suppression, yawning and more nausea along with it. For libido alone, PT-141 is the cleaner tool.
Does PT-141 tan your skin?
A little, with repeated use. It has weak MC1R activity, so pigmentation is minor at normal doses, but darkening of skin, gums and moles is a listed side effect, especially in people with darker skin. It is not a tanning peptide.
Which causes more nausea, PT-141 or Melanotan 2?
Both are rough early. PT-141 caused nausea in about 40 percent of trial participants at the 1.75 mg dose, with about 8 percent stopping because of it. Melanotan II nausea is described as nearly universal for the first several doses. Lower starting doses and evening dosing help with both.
Can you take PT-141 and Melanotan 2 together?
Rarely done and not studied. They overlap at MC4R, so the sexual effect would not add much, and both raise blood pressure and cause nausea, which would stack. People wanting a tan plus libido effect usually use Melanotan II alone.
Is PT-141 approved for men?
No. Vyleesi is approved for premenopausal women with hypoactive sexual desire disorder. Earlier trials in men with erectile dysfunction showed improved erections, and off label use in men is widespread, but there is no approved male indication.
Related reading
Same tan, different side effects. Which melanotan is which?
The bonding hormone against the approved desire drug. Which one does what people hope, and which one is mostly placebo?
Guide
Safety
Guide
Safety
Sources
- 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
- Melanotan-II, a cyclic alpha-MSH analog, induces tanning in human volunteers. Journal of Clinical Endocrinology and Metabolism, 1996