Melanotan II with PT-141
Melanotan II with bremelanotide (PT-141)
Written by Aaron CuhaReviewed Sep 2026
Also known as: MT-2 PT-141 stack, Tan and libido stack
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Two tanning and libido peptides run together. Here is the part nobody mentions. PT-141 is what your body turns melanotan II into. So this is one drug and its own breakdown product, taken at the same time. That is not two things.
What people take it for
- Erections and sex drive.
- Getting a tan with less sun.
- Appetite suppression, which comes along for the ride.
What the trials actually showed
Nobody has tested the pair. Each has its own trial. Ten men with erection problems and no physical cause got melanotan II or a dummy shot in a blinded crossover. Eight of the ten got clear erections. Firm erections lasted 38.0 minutes on the drug against 3.0 minutes on the dummy. Nausea, yawning, stretching and lower appetite were more common on the drug. A second study looked at men whose problem did have a physical cause. PT-141 has two big phase 3 trials in women with low sex drive, which is what it is approved for. Nobody has ever run a trial of melanotan II for tanning, which is what most people buy it for.
What people report
Reports, not trial results
The good
- Erections and more desire, which is the point.
- A tan without much sun, from the melanotan half.
The bad
- Nausea and flushing in the first hour. This is the most common report and it showed up in the real trial too.
- Yawning and stretching you cannot stop. Also in the trial.
- Moles and freckles going darker, and new dark spots.
- Headache, and higher blood pressure readings at bigger doses.
- The mole problem is the serious one. A changing mole is the main early warning sign for skin cancer. This drug changes all of them.
Where these come from: The nausea, yawning and stretching are from the controlled trial. The pigment changes come from a dermatology review of unregulated use of these drugs and from user forums.
My bottom line
One of these two is a metabolite of the other, so stacking them is just more of one drug. And if you have unusual moles or any melanoma in the family, do not take something whose whole job is to darken them.
An opinion, not a finding. I am a coach, not a doctor.
Overview
Two melanocortin agonists run together, one of which is the active metabolite of the other. That is the whole problem: bremelanotide is what melanotan II becomes in the body, so this is one drug class hit twice, with the pigment-inducing parent and its approved metabolite in the same session. Vial sizes are not consistent and the combination has never been studied.
Bremelanotide, sold as PT-141, is a metabolite of melanotan II. That relationship is the reason both exist and it is the reason stacking them makes very little pharmacological sense.
Melanotan II is a cyclic alpha-melanocyte stimulating hormone analogue. In a double-blind placebo-controlled crossover study in ten men with psychogenic erectile dysfunction, clinically apparent erections developed in 8 of 10 treated men, and mean duration of tip rigidity above 80% was 38.0 minutes on melanotan II against 3.0 minutes on placebo, at p = 0.0045. Transient nausea, stretching and yawning, and decreased appetite were more frequent than on placebo. A separate randomised study extended the work to men with organic erectile dysfunction. Melanotan II also causes what it is mostly bought for, which is pigmentation, because it agonises the melanocortin 1 receptor.
Bremelanotide was developed as the version without the pigment problem and it is an approved medicine. In two randomised phase 3 trials it was studied for hypoactive sexual desire disorder in premenopausal women, which is the indication it holds.
Running them together therefore means taking a melanocortin agonist and its own metabolite at the same time. The receptor targets overlap, the side effects overlap, and the nausea in particular is a melanocortin class effect rather than a quirk of either molecule. A stack of the two is closest to a larger dose of one, with the added certainty of pigmentation from the parent.
The unregulated use of these analogues carries a specific dermatological concern that belongs on this page. A review of the risks of unregulated alpha-MSH analogue use covers the dermatological consequences reported in users, and melanotan II is bought precisely to darken skin and moles, which is the opposite of what dermatological advice recommends for anyone with atypical naevi. No vial size is canonical across sellers, so this page does not state a per-unit amount.
Mechanism of action
Both are non-selective melanocortin receptor agonists. Bremelanotide acts largely through melanocortin 4 receptor signalling in the central nervous system, which is the sexual desire pathway. Melanotan II adds strong melanocortin 1 receptor agonism in melanocytes, which is the pigmentation pathway, and is metabolised in part to bremelanotide. Stacking a parent compound with its own metabolite gives one pharmacology, not two.
Human evidence
Each component has human trials. The stack does not, and the two are pharmacologically the same class with one being a metabolite of the other.
- The stack: no published study, no registered trial.
- Melanotan II: 8 of 10 men developed clinically apparent erections in a placebo-controlled crossover, with 38.0 minutes of tip rigidity above 80% against 3.0 minutes on placebo.
- Bremelanotide: two randomised phase 3 trials in premenopausal women with hypoactive sexual desire disorder, the basis for its approval.
- Nausea is a class effect of melanocortin agonism and appeared in the melanotan II trial.
- Unregulated alpha-MSH analogue use has its own reported dermatological risk literature.
What this does not tell you: No trial has examined what happens when a melanocortin agonist is taken with its own metabolite, and no trial has studied melanotan II for pigmentation, which is what most buyers actually want from it.
What it has been measured to do
Measured in people
Goals Melanotan II with PT-141 has been measured for in a human being, most people first. Counts come from the study lines on this page and deliberately undercount.
- Feeling less hungry10 people · 1 study
- Libido and sexual functionno headcount stated · 1 study
What people using it report
Uncontrolled and self-selected, so it cannot show that anything works. It is still the best guide on this page to what people actually do with Melanotan II with PT-141, what they expect, and what goes wrong. The full account, including the negative reports, is below.
32 of the 36 indexed goals have no study of any kind behind Melanotan II with PT-141
No trial, no animal work, no cell work on this page reports a result for these. That is an absence of evidence rather than evidence of absence, but it does mean anything you have been told about Melanotan II with PT-141 and one of these did not come from a study cited here.
Reading the research record
The pharmacological point is the useful one: bremelanotide is a metabolite of melanotan II, so running both is not combining two agents. It is taking a drug and its downstream product together, at a total melanocortin exposure neither trial studied.
The dermatological point is the serious one. Melanotan II darkens skin by agonising the receptor that drives melanin production, and it darkens existing naevi along with everything else. That interferes with the single most useful thing about moles, which is that a change in one is a warning sign. Anyone with atypical naevi, a personal or family history of melanoma, or a skin type that burns has a specific reason to avoid a drug whose entire purpose is to change how their moles look.
The evidence, charted
Fig. 1a · evidence scale
10people, across 1 human study cited here
- 1998 · Journal of Urology10100%
The whole total is one study of 10. Counts are the enrollment each human citation on this page states, which includes observational cohorts where nobody was given the compound. 2 further human citations state no participant count and are not counted here. Studies still recruiting are excluded, and only studies cited on this page are counted.
Fig. 1b · evidence mix
3 of 4 citations here are human work, the rest is not.
- Human · given to people375%
- Review · summarises other work125%
Counted from the citation list on this page, typed as this page types it. It understates any literature larger than the sources we cite, and a review counts once however many studies it covers.
Fig. 2 · evidence over time
Evidence spans 4 distinct years, 1998 to 2019, counted from the citation list on this page. The newest citation on file is from 2019, more than five years ago; the published record may have gone quiet.
Fig. 3 · legal status at a glance
US
Not approved
UK
Not approved
AU
Not approved
CA
Not approved
Not approved in any of the four jurisdictions shown. A jurisdiction's classification is a regulatory fact, not a verdict on the science; see Legal status below for the full text and any notes.
Fig. 4 · dose response
No human dose response curve exists
We draw this figure where the data supports it. For this compound in humans it does not, so the panel stays empty rather than borrowing an animal curve and implying it transfers.
Fig. 5 · molecular identity
- Modality
- Blend
- Molecular weight
- Not on file
- Half-life
- Stated in words, not a number
- Sequence length
- None on file
see the exact wording below
Half-life as stated on file: Not defined for the pairing. Both are used episodically rather than on a fixed schedule, and no pharmacokinetic study of the two together exists.
No amino acid sequence is on file for Melanotan II with PT-141, which is expected: a blend is not built from residues.
Fig. 6 · what is in the vial
No mass split can be drawn for this blend
Sellers do not publish a consistent vial size for Melanotan II with PT-141, so the share of each component is not knowable from the outside. Splitting the bar evenly would invent the number this page exists to question.
- Melanotan IIamount not stated
- Bremelanotide (PT-141)amount not stated
Component list from the product labels we hold. Amounts are label mass, never a dose.
Key studies & citations
- Human1998
Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study
Ten men with erectile dysfunction of no known organic cause, double-blind placebo-controlled crossover with real-time RigiScan monitoring over six hours. Clinically apparent erections developed in 8 of 10 men on melanotan II. Mean duration of tip rigidity above 80% was 38.0 minutes on melanotan II against 3.0 minutes on placebo, p = 0.0045. Transient nausea, stretching and yawning, and decreased appetite were more frequent on melanotan II.
Journal of Urology - Human2000
Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction
A randomised study of the same class of alpha-MSH analogue in men with organic rather than psychogenic erectile dysfunction, extending the erection and sexual desire findings to a harder population. Small, and again with the melanocortin class side effects.
Urology - Human2019
Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder: Two Randomized Phase 3 Trials
Two randomised phase 3 trials of bremelanotide in premenopausal women with hypoactive sexual desire disorder, the studies behind its approval. This is the evidence for the metabolite half of the stack, in women, for desire rather than erection.
Obstetrics and Gynecology - Review2017
Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review
A dermatology review of what has been reported in people using unregulated alpha-MSH analogues, which is the relevant safety literature for melanotan II because the drug has never been through a regulatory safety programme.
International Journal of Dermatology
What users report
Self-reported experiences, not evidence. Nothing below was measured under controlled conditions, and reports like these cannot separate a real effect from placebo, from the training or diet change that accompanied it, or from what the product actually contained. They are here because knowing what people describe, including what goes wrong, is worth reading alongside the studies.
- Nausea and flushing within the first hour, the most consistent report on either molecule.
- Spontaneous yawning and stretching, which is a recognised melanocortin effect and appeared in the controlled trial.
- Erections and increased desire, which is what both are taken for.
- Darkening of existing moles and freckles, and new dark spots, on the melanotan II half.
- Appetite suppression.
- Headache and, at higher amounts, a raised blood pressure reading.
Sources: The nausea, yawning and stretching appear in the melanotan II controlled trial. The pigment changes and the rest come from forums including r/peptides and from the dermatological review of unregulated alpha-MSH analogue use.
Frequently asked questions
Why is stacking these two a problem?
Bremelanotide is a metabolite of melanotan II. Taking both means taking a drug and its own downstream product together, which is one pharmacology at a higher total exposure rather than two mechanisms.
What did the melanotan II trial show?
In ten men with psychogenic erectile dysfunction, 8 of 10 developed clinically apparent erections, with mean tip rigidity above 80% lasting 38.0 minutes against 3.0 minutes on placebo.
Is the tanning effect studied?
Not in a trial. Pigmentation is what melanotan II is mostly bought for and it has never been through a controlled study for that purpose, which is also why nobody has characterised its long-term skin risk.
Who should not use melanotan II?
Anyone with atypical moles, a personal or family history of melanoma, or a skin type prone to burning. Darkening moles removes the visual change that is the main early warning sign for skin cancer.
Is either one approved?
Bremelanotide is approved for hypoactive sexual desire disorder in premenopausal women. Melanotan II is not approved anywhere and has drawn regulator warnings in several countries.