Question 1

What is the Melanotan peptide?

Accepted Answer

Melanotan is a label for two research compounds, not one, and sorting out which is which comes first. Melanotan-I is the molecule with human pigment data behind it. A 2000 study names it as [Nle4-D-Phe7]alpha-MSH, also called Melanotan-I (MT-I). Melanotan-II is built to a different shape. A 1996 pilot describes the lactam-bridged molecule, called Melanotan-II (MT-II), meaning a short peptide closed into a ring. Both are copies of α-MSH, the body's own tanning signal. A 2022 case report says that signal stimulates the production of eumelanin to get skin pigmentation. Eumelanin is the brown-black pigment a tan is made of. A 2020 case report calls Melanotan II a non-selective melanocortin-receptor agonist, so one shot reaches several receptors at once rather than just one. In the shorthand people search with, MT-2 and melanotan 2 always mean the second molecule.

Question 2

What is the difference between Melanotan 1 and Melanotan 2?

Accepted Answer

Shape, evidence and legal standing all differ, and the last of those is what catches people out. The evidence divides cleanly. The human pigment work, with biopsies and a laboratory assay, was done with Melanotan-I. The human erection work was done with Melanotan-II. No study among the research behind this page has given both molecules to the same people, so every comparison a reader meets is stitched from two sets of volunteers, two decades apart. Standing diverges much further than shape does. A 2015 review records that afamelanotide is a prescription medicine for a rare disorder in which sunlight causes pain, and in the same sentence notes that structurally related α-MSH derivatives are available via the internet. A 2014 case report states that Melanotan-II is unlicensed and incompletely tested, so the extent and types of adverse effects are unknown. Reading a finding about one of them as a finding about the other is the easiest mistake on this subject, and it runs in both directions rather than one.

Question 3

Has Melanotan been tested in people?

Accepted Answer

Three times, if the bar is a study that gave it to volunteers and measured a result, and all three were finished before 2001. The largest is the crossover study in erectile dysfunction. Melanotan II was administered to 20 men with psychogenic and organic ED using a double-blind placebo-controlled crossover design. That is the only controlled human test either molecule has had. The tanning work is smaller. In the 1996 pilot, a placebo-controlled trial was conducted in 3 normal male volunteers, and the Melanotan-I study is the more careful of the two. Seven normal volunteers (six males and one female) with tanning skin types III or IV were given 10 daily subcutaneous injections, and forearm skin was biopsied so pigment could be measured rather than guessed at. Everything else published about people is a case report. One trial is open now: Melanotan II (MT-II) as an Adjunct to NB-UVB Phototherapy for Repigmentation in Stable Nonsegmental Vitiligo is listed as RECRUITING, so it is still enrolling and has reported nothing.

Question 4

Does MT-2 actually change skin colour?

Accepted Answer

In the small amount of human work that exists, yes, and the measurement behind that yes was crude. Two of the three volunteers in the 1996 pilot had increased pigmentation in the face, upper body and buttock, as measured by quantitative reflectance and by visual perception, 1 week after MT-II dosing ended. Quantitative reflectance is a light meter held against skin, so the result rests on a meter reading and somebody looking. The authors kept their claim narrow: these results demonstrate that MT-II has tanning activity in humans given only 5 low doses every other day by subcutaneous injection. What no study covered here has shown is how dark, how fast, or how reliably. No study among the research behind this page has measured a dose-response curve for pigment in people. The direction is clear; the size of it rests on a few readings in eight volunteers rather than on anything a reader could plan around. Where the colour change was measured, how long it lasted and who was measured are set out at the Melanotan results page.

Question 5

Does Melanotan 1 make you tan?

Accepted Answer

This is the one Melanotan question with a direct human measurement under it, and the answer is a qualified yes. Seven volunteers were injected daily for two weeks in a 2000 study. This regimen induced tanning at 3 of 8 anatomic sites including the face, neck and forearm, which is worth saying the other way round as well: five of the eight sites did not change. The pigment itself was measured rather than eyeballed. Skin samples showed that the mean increase in forearm skin PTCA levels was 98%, PTCA being a laboratory marker that stands in for eumelanin. The mix of pigments moved too: the eumelanin to pheomelanin ratio in forearm skin went from 51:1 at baseline to 86:1 following MT-I, pheomelanin being the red-yellow pigment. That is a real change in human skin chemistry, from seven people, in a single study that no other paper in this record has repeated.

Question 6

How long does it take to tan with Melanotan 2?

Accepted Answer

No study among the research behind this page has measured how long a visible tan takes to appear in a person given Melanotan-II. Both tanning investigations recorded their measurements on days fixed in advance, which is a scheduling decision rather than an observation of onset. What the record provides is the shape of those schedules. In the 1996 pilot, subcutaneous injections of MT-II or saline were given daily (Monday-Friday) for 2 consecutive weeks, and the pigment comparison came a week after dosing finished. The Melanotan-I study ran the same way, comparing baseline against the end of the daily dosing period, (day 14), and then against day 21. Read that carefully, because it determines the limit on what either investigation can legitimately claim. Both establish that pigment was higher two or three weeks in. Neither can say when it started, because nobody looked on day three or day eight. The question people are actually typing, which is how many days until this shows, has not been asked in a published study of either molecule. The amounts attached to those schedules are a separate matter: The Melanotan dosage page carries them study by study, alongside the arithmetic of a vial.

Question 7

Do you still need sun exposure when taking MT-2?

Accepted Answer

No study among the research behind this page has compared Melanotan with and without ultraviolet light in the same people, which is what settling this would take. Two things are known separately. Tanning was measured serially using computerized light reflectance in the Melanotan-I volunteers, who were only injected, with no sunbed anywhere in the design. A 2014 case report documents the other practice. A 20-year-old woman was referred to a dermatology clinic, having conducted a 3- to 4-week course of self-injections with MT-II, intending an augmentation of sunbed tanning. A melanoma was excised three months later. A 2025 history of tanning technology describes how these injections arrived as alternatives to sunbeds and sunbathing, and notes that they reinvigorated tanning culture overall. So the molecule plainly does something on its own. The honest position is that the injection-only route has one small study behind it, the combined route has case reports, and the comparison that would separate them is missing from these sources rather than merely hard to find.

Question 8

Does MT-2 burn fat?

Accepted Answer

No study among the research behind this page has measured body fat or body weight in a person given Melanotan-II. It is among the most asked questions about this compound. The animal record is not empty, and it points somewhere narrower than fat loss. In a 2005 rat study, leptin and melanotan-II were injected straight into a brain cavity at doses matched for appetite, and the two caused comparable increases in plasma ACTH and corticosterone levels, which are stress hormones. The same experiment then found that anorexigenic efficacy of melanotan-II, meaning how hard it damped appetite, was not correlated with any parameter linked to DIO, which is diet-induced obesity in rats. A 2018 study adds a wrinkle: Melanotan II given to mice causes a profound, transient hypometabolism/hypothermia, so their metabolism slows and their body temperature falls. What is on record is appetite suppression in rodents, delivered into the brain, with no link to body fat in those same animals. That is not the same question as fat loss in a person, and the second one has not been asked.

Question 9

Does MT-2 increase testosterone?

Accepted Answer

No study among the research behind this page of Melanotan-II reports a testosterone measurement, in people or in animals. What gets borrowed to answer this is the erection work, and that work points away from hormones rather than towards them. In the 2000 crossover trial, in the absence of sexual stimulation, Melanotan II led to penile erection in 17 of 20 men. Increased sexual desire was reported after 13 of 19 doses in the same trial, against 4 of 21 doses of placebo, which is a wide gap for a study of this size. A 2006 rat study then asked where the effect comes from, and the answer was nerves. In those rats, erectile responses elicited by cavernous nerve stimulation were increased after intravenous melanotan-II. The facilitator effect of melanotan-II was abolished after acute removal of the lumbar paravertebral sympathetic chain, which is a bundle of nerves beside the spine. A response that stops when a nerve bundle is removed is a nervous-system effect rather than a hormonal one, and no study in these sources measured testosterone alongside it.

Question 10

Can Melanotan 2 make your eyes lighter?

Accepted Answer

No study among the research behind this page has measured eye colour in anybody given Melanotan-I or Melanotan-II, and none of the human reports looked at eyes at all. Every pigment measurement on record runs the other way. In the Melanotan-I study, eumelanin was also measured in the forehead skin samples of three subjects, and the numbers went up rather than down. A 2013 case report is titled Melanotan-associated transverse melanonychia, a dark band across a nail. A 2019 review of sudden crops of new moles traced its cases to immunosuppressive agents, chemotherapy or melanotan (41%). A 2015 review states that Melanotan I leads to the activation of dysplastic nevi, which are moles with odd features. Skin, nails, moles: the direction on record is darker, in the tissues where pigment cells sit. A lighter iris would be the opposite of what every published measurement shows, and no study among the research behind this page has looked for it. What circulates about eye colour is reported experience, and reported experience and measured outcome are different questions.

Question 11

How long does Melanotan last in the body?

Accepted Answer

Two clocks run through this question and they give very different answers, which is where the confusion starts. The first is how fast the molecule leaves. In a 1994 study, the pharmacokinetic profile of the melanotropic peptide, melanotan-II (MT-II), was determined in rats, pharmacokinetics meaning the study of how fast a compound is taken up and cleared. A 2007 study in mice is blunter: following administration of MT-II, clearance from plasma was rapid. Brain levels stayed low: the high plasma levels of MT-II at the same time point confirmed the low penetrability of the peptide in mouse brain. The second clock is the pigment, and it runs for weeks: the 1996 pilot read its tanning result 1 week after MT-II dosing ended, and the Melanotan-I volunteers were still being measured on day 21. No human study of how either molecule is cleared has been published, so both numbers belong to rodents. A compound gone from the blood within hours and a tan visible a fortnight later are measuring different things rather than contradicting each other.

Question 12

Is Melanotan legal? Is it approved?

Accepted Answer

Nothing sold as melanotan is an approved medicine, and the one approved molecule in this family is not sold under that name. A 2015 review draws the line in one sentence. Afamelanotide is a prescription medicine for a rare light-sensitivity disorder, while structurally related α-MSH derivatives are available via the internet. The other half comes from case reports. A 2012 one calls melanotan tanning injections unlicensed compounds with an unproven safety record. A 2014 one adds that Melanotan-II is unlicensed and incompletely tested. FDA records hold three recalls, and one covers Melanotan I 200mcg/mL vials from a compounder, pulled for Lack of Assurance of Sterility. Two cover Melanotan II: one for Lack of sterility assurance, one for faults that call into question the sterility of products intended to be sterile. Every one of those is about how a batch was made, not about the molecule in it.

Question 13

Is Melanotan safe?

Accepted Answer

No controlled study has ever assessed harm from either molecule, and the whole harm record is built from case reports. A 2026 review of tanning agents states that unregulated melanotan I and II use has caused serious adverse effects, including rhabdomyolysis, renal infarction, and priapism. Those are muscle breakdown, a blocked kidney artery and a long painful erection, and the published cases also run to melanoma, sudden crops of new moles and skin ulcers at injection sites. Set against that, the deliberate human exposure on record is three volunteers in 1996 and twenty men in 2000. A 2014 report says plainly that Melanotan-II is unlicensed and incompletely tested, so the extent and types of adverse effects are unknown. Case reports count the people who reached a clinic; that is not a rate, and nobody knows the number to divide by. The organ-specific questions readers ask, about kidneys, heart, blood pressure, moles and daily use, are taken one at a time at the Melanotan safety page.

Question 14

How does Melanotan work?

Accepted Answer

Both molecules copy α-MSH, the signal that reaches pigment cells and shifts them between two kinds of melanin. The Melanotan-I study shows that shift in human volunteers: the course increased the eumelanin: pheomelanin ratio in forearm skin from 51:1 at baseline to 86:1 following MT-I. Eumelanin is brown-black and pheomelanin red-yellow, so this kind of tan changes which pigment gets made. The receptor side is less tidy. Melanotan II is a non-selective melanocortin-receptor agonist, which is why one injection reaches pigment, appetite and erection at once. A 2006 rat study found that central and peripheral melanocortin pathways are recruited by melanotan-II, depending on how it is given. Some of it may not involve those receptors at all. In a 2018 study the drop in body temperature after melanotan II was preserved in mice lacking any one of melanocortin receptors 1, 3, 4, or 5. It was abolished in mice that lack mast cells, which release histamine. The released histamine produced hypothermia via histamine H1 receptors instead. A second, unintended route of action in mice is worth knowing before anyone takes the receptor account as complete.

Melanotan