Comparison
MT1 vs MT2: Melanotan 1 and Melanotan 2 Compared
Published by Peptara Labs · Updated · How we research and check our pages
The short answer
MT1 vs MT2 comes down to which melanocortin receptors each peptide reaches, since they are two different melanocortin peptides. Melanotan 1 (afamelanotide) leans toward MC1R, the pigment receptor, and is an approved medicine for a rare light-sensitivity condition (FDA approval, 2019). Melanotan 2 is non-selective across MC1R, MC3R, MC4R and MC5R, is not approved by a major regulator, and is reported to produce effects beyond pigment because of that wider receptor reach. Neither is approved for cosmetic tanning.
This page is general educational information, research-use framing only, not medical advice. It does not rank the two compounds and does not tell anyone what to take. Any decision about a research compound belongs with a qualified clinician.
The difference everything else follows from: receptor selectivity
Both compounds are analogs of alpha-melanocyte-stimulating hormone (alpha-MSH), the natural hormone that regulates pigment. They differ in how narrowly they act.
Melanotan 1 is a linear alpha-MSH analog with two substitutions (Nle at position 4 and D-Phe at position 7) that make it more stable and longer-acting than the natural hormone. It leans toward the melanocortin-1 receptor. MC1R is a Gs-protein-coupled receptor: when an agonist such as alpha-MSH or afamelanotide binds it, the cell raises its cyclic AMP signal, which shifts melanogenesis toward eumelanin, the darker pigment that absorbs and scatters UV light (Herraiz et al., 2021, Pigment Cell Melanoma Res).
Melanotan 2 is a cyclic, shortened analog and is non-selective, acting at MC1R, MC3R, MC4R and MC5R. Receptor focus is what separates the family: MC1R governs pigment, MC4R is linked to appetite and sexual function, and MC3R and MC5R have other roles. That is the mechanistic reason reports of melanotan 2 describe effects beyond tanning while melanotan 1 is documented mainly for pigment.
Why this framing
Receptor selectivity is a structural fact about each molecule, and it is the only thing in this comparison that does not depend on how much research each compound happened to attract. Read the rest of the page through it.
What published research reports on the tanning response
For melanotan 1, added pigment is not a side effect of the approved use, it is the point of it. Afamelanotide is approved for adults with erythropoietic protoporphyria (EPP), a rare inherited condition in which sunlight triggers skin pain, and the eumelanin the compound raises is the basis for that approved use (FDA approval, 2019). The pigment pathway itself is the MC1R signaling described above (Herraiz et al., 2021).
For melanotan 2, the pigmentation reports are the reason the compound is known at all, but they sit on a much thinner record. Melanotan 2 has not been through a registered program comparable to the one behind afamelanotide, so there is no approved labeling to quote and no trial dataset that puts a number on how much pigment change to expect or how quickly. Our own melanotan 2 material describes the peptide as priming the skin to produce more melanin, with a light stimulus still required to trigger the response, which means exposure is part of any outcome rather than something the compound removes.
We have no head-to-head study of the two compounds to cite, so nothing here should be read as one being a stronger tanning agent than the other. What can be said from the record is narrower and more useful: one has an approved use built on the pigment it produces, and the other has reports without a program behind them.
Reported side-effect profiles, kept apart on purpose
These two lists are not the same kind of object. One is an approved adverse-reaction list. The other is a set of commonly reported effects with no registered trial program quantifying them. Presenting them in a single merged column would imply an equivalence that does not exist, so they stay in separate cards.
Melanotan 1
As listed in approved labeling
- Nausea (19 percent) and fatigue (6 percent)
- Reactions where the implant is placed (21 percent)
- Darkening of skin, and of moles
- A full-body skin examination twice a year is recommended in the approved labeling
Scenesse prescribing information; FDA approval, 2019.
Melanotan 2
Commonly reported, not trial-quantified
- Nausea and facial flushing, commonly in the first hour after a dose
- Reduced appetite
- Darkening of existing moles and freckles
- Spontaneous erections in men, attributed to the melanocortin pathway
Reported effects, with no registered trial program putting a frequency on any of them.
One class-level reference point does exist, and it is worth reading precisely. PT-141 (bremelanotide) is chemically derived from melanotan 2 and went through a phase 3 program: nausea was reported in about 40 percent of participants, alongside flushing, headache, and transient rises in blood pressure with small decreases in heart rate (Kingsberg et al., 2019). The approved labeling for the same compound separately records focal hyperpigmentation with more frequent dosing (Vyleesi prescribing information). Those are bremelanotide numbers. They describe what the melanocortin class can do, not what melanotan 2 does at any particular amount, and they are not a substitute for data melanotan 2 does not have.
Both compounds are reported to darken moles. The approved afamelanotide labeling recommends a full-body skin examination twice a year for that reason (FDA approval, 2019), and our own melanotan 2 material treats documenting moles before first use as non-negotiable and states that anyone with a personal or family history of melanoma or atypical moles should not use it and should see a dermatologist.
Which research contexts each one appears in
Melanotan 1 appears as a medicine
Its strongest human record is the approved product: an implant placed by a healthcare professional for adults with EPP, with a labeled adverse-reaction list and a recommended skin monitoring schedule (Scenesse prescribing information; FDA approval, 2019).
It also appears in the pigmentation literature as an MC1R agonist, which is where the mechanistic work on eumelanin sits (Herraiz et al., 2021).
Melanotan 2 appears as a research material
It is supplied as a research compound rather than a medicine, and reports of its use describe pigmentation alongside appetite and sexual effects consistent with its wider receptor reach. Human safety data is limited.
Its most consequential appearance in the literature is indirect: PT-141 (bremelanotide) was derived from it and developed toward MC4R for sexual function, and that program is where the family accumulated its phase 3 evidence (Kingsberg et al., 2019).
MT1 vs MT2 at a glance
No column in this table wins. Where melanotan 2 has no comparable source, the cell says so instead of leaving a gap that would read as nothing to report.
| Dimension | Melanotan 1 (MT1) | Melanotan 2 (MT2) |
|---|---|---|
| Other names | Melanotan-1, melanotan I, afamelanotide, Scenesse | Melanotan 2, melanotan II, MT-2, MT2 |
| Structure | Linear alpha-MSH analog (Nle at position 4, D-Phe at position 7) | Cyclic, shortened analog |
| Receptor focus | Leans toward MC1R, the pigment receptor | Non-selective across MC1R, MC3R, MC4R and MC5R |
| Main documented action | Pigment: raises eumelanin, the darker pigment that absorbs UV light | Pigment, plus reported appetite and sexual effects consistent with MC3R and MC4R activity |
| Regulatory status | Approved for erythropoietic protoporphyria in adults (FDA approval, 2019) | Not approved by a major regulator for any use |
| How it is delivered in its studied setting | A 16 mg subcutaneous implant placed by a clinician roughly every two months | Lyophilized powder reconstituted for subcutaneous injection, with no approved dose |
| Strength of the human record | An approved label with a documented adverse-reaction list | Limited; commonly reported effects are not quantified by a registered trial program |
| Approved for cosmetic tanning | No | No |
The 16 mg implant figure is the FDA-approved label specification for afamelanotide, not a dose an individual selects, and it has no counterpart on the melanotan 2 side because no approved dose exists there.
What this comparison cannot tell you
Three limits are worth stating outright, because a tidy table hides them well.
- There is no head-to-head trial. Everything above compares two separate records, one of them much thinner than the other.
- Neither is approved for cosmetic tanning. The afamelanotide approval covers EPP only, and melanotan 2 has no approval at all, so the cosmetic use that drives most of the interest in both compounds is the use with the least data behind it.
- Limited data is not a safety finding. The absence of quantified adverse events for melanotan 2 reflects the absence of a program that would have counted them, and reads as a gap rather than as reassurance.
Reading further on each compound
Each compound has its own page here, with the full detail this comparison compresses.
Keep reading
Each compound in full, plus the family they both belong to
Melanotan-1 (afamelanotide)
The MC1R side of this comparison in full, including the approved EPP use.
Melanotan 2 (MT-2)
The 10mg research vial, its batch COA, and the two precautions it carries.
Melanotan 2 complete guide
Mechanism, the mole and blood-pressure precautions, storage.
How to reconstitute Melanotan 2
The mixing steps and the units math for a 10mg vial.
PT-141 (bremelanotide)
The MC4R member of the same family, and the one with phase 3 data.
Peptide side effects
How reported effects differ from trial-quantified ones across compounds.
Peptide glossary
Plain definitions for agonist, analog, lyophilized, and the rest.
MT1 vs MT2: FAQ
Is Melanotan 1 safer than Melanotan 2?
Research does not answer that as a ranking, and this page will not turn it into one. What the record supports is a difference in how much is known. Melanotan 1 (afamelanotide) went through a registered program and carries an approved label, so its reported reactions are documented in one place: implant site reactions in 21 percent, nausea in 19 percent, fatigue in 6 percent, and darkening of skin and moles, with a full-body skin examination twice a year recommended (Scenesse prescribing information; FDA approval, 2019). Melanotan 2 has no approval from a major regulator and no comparable registered program, so its commonly reported effects come from reports rather than from a trial dataset that quantifies how often they occur. A documented profile and an unquantified one are not two points on the same scale, and thin data is not the same as a clean record. Both compounds are reported to darken moles, which is why skin monitoring is emphasized for each.
What is the actual difference between MT1 and MT2?
Receptor selectivity, and everything else follows from it. Melanotan 1 is a linear analog of alpha-melanocyte-stimulating hormone that leans toward the melanocortin-1 receptor (MC1R), the receptor most tied to skin and hair color, so its main documented action is pigment. Melanotan 2 is a cyclic, shortened analog that is non-selective across MC1R, MC3R, MC4R and MC5R, so reports describe effects beyond pigment, including appetite and sexual effects that reflect MC3R and MC4R activity. The second difference is regulatory: afamelanotide is an approved medicine for a rare light-sensitivity condition, and melanotan 2 is not approved by a major regulator.
Is either MT1 or MT2 approved for cosmetic tanning?
No. Afamelanotide (melanotan 1) is approved only for erythropoietic protoporphyria in adults and is given as a clinician-placed implant (FDA approval, 2019). Melanotan 2 has no approval from a major regulator for any use. No melanotan product is approved for cosmetic tanning, and human safety data for that use is limited.
Do MT1 and MT2 both darken moles?
Both are reported to. For melanotan 1 the approved labeling states it can darken moles as well as skin, which is why that labeling recommends a full-body skin examination twice a year (Scenesse prescribing information; FDA approval, 2019). For melanotan 2, darkening of existing moles and freckles is among the commonly reported effects, and it is the reason our own melanotan 2 material treats documenting moles before first use as non-negotiable and states that anyone with a personal or family history of melanoma or atypical moles should not use it. Neither statement is a safety comparison; it is the same signal reported in two settings with very different amounts of data behind them.
Why does MT1 come as an implant and MT2 as a vial of powder?
Because one is a finished medicine and the other is a research material. Afamelanotide is delivered as a 16 mg subcutaneous implant placed by a trained clinician roughly every two months, which is the approved product specification rather than something an individual titrates (Scenesse prescribing information; FDA approval, 2019). Melanotan 2 is supplied as a lyophilized powder for reconstitution, with no approved dose behind it. That difference in format is a difference in regulatory status, not evidence that either one is better.
Where does PT-141 fit next to MT1 and MT2?
PT-141 (bremelanotide) is the third member of the same family and the one with a completed phase 3 program behind it. It is chemically derived from melanotan 2 but was developed for a different target, MC4R signaling linked to sexual arousal, and it is approved for a sexual-desire disorder. Its phase 3 program is useful here as a class reference point: nausea was reported in about 40 percent of participants, alongside flushing and headache, and transient rises in blood pressure with corresponding reductions in heart rate (Kingsberg et al., 2019). The approved labeling for the same compound separately records focal hyperpigmentation with more frequent dosing (Vyleesi prescribing information). Those are bremelanotide figures, not melanotan 2 figures, and they are quoted as the melanocortin class signal rather than as a substitute for data melanotan 2 does not have.
Has anyone compared MT1 and MT2 head to head?
Not in any source we can cite. Everything on this page is drawn from what each compound has been reported on separately: an approved label and its supporting program for afamelanotide, published receptor pharmacology for the melanocortin family, and reported effects for melanotan 2 that no registered trial program has quantified. A comparison assembled from two separate records is not the same as a head-to-head trial, and we would rather say that plainly than imply a study exists.
References
- U.S. Food and Drug Administration. Scenesse (afamelanotide) implant, prescribing information; FDA approval, October 8, 2019.
- Herraiz C, et al. The alpha-melanocyte-stimulating hormone/melanocortin-1 receptor interaction: a driver of pleiotropic effects beyond pigmentation. Pigment Cell Melanoma Res. 2021.
- U.S. Food and Drug Administration. Vyleesi (bremelanotide) injection, prescribing information, section 5.2, focal hyperpigmentation.
- Kingsberg SA, Clayton AH, Portman D, et al. Bremelanotide for the treatment of hypoactive sexual desire disorder: two randomized phase 3 trials (RECONNECT). Obstet Gynecol. 2019;134(5):899-908.
General educational information only, research-use framing, not medical advice. Neither compound on this page is approved for cosmetic tanning. Confirm the current status where you live and consult a qualified professional before acting.