Melanotan II
The 'Barbie Drug', Tanning Peptide, PT-141's Ancestor
Evidence grade 2 of 5, Thin. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Not FDA-approved; formal warnings from FDA, MHRA, TGA
Reference only. Not medical advice.
What can go wrong
Non-selective melanocortin activation causes nausea, facial flushing, and darkening of existing moles/new nevi. Because MT-II is mitogenic to melanocytes, at least four peer-reviewed case reports describe melanoma emerging during or after use, and regulators (FDA, MHRA, TGA) warn of a theoretical melanoma-promotion risk, compounded by users combining it with deliberate sun/UV exposure. Priapism (prolonged, painful erection requiring emergency care) is a documented risk. All product is illicit and unregulated.
This is something to take to a clinician. The Atlas can tell you what is known about melanotan ii in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
Melanotan II (MT-II) is a synthetic non-selective analog of alpha-melanocyte-stimulating hormone (alpha-MSH), developed to induce skin tanning by stimulating melanin. Nicknamed the 'Barbie drug,' it is sold illegally online as an injectable tanning agent. During its development, its strong pro-erectile and libido effects were noticed, an observation that led directly to bremelanotide (PT-141), the selective melanocortin agonist later FDA-approved as Vyleesi. MT-II itself remains unapproved and carries broad safety warnings.
Bought online to tan; erections were the side effect that launched a real drug.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
Combinations named above are how people use these compounds together, under names the community gave them. The combinations themselves have not been studied. Evidence for one compound is not evidence for a pair.
How it is supposed to work
MT-II broadly activates melanocortin receptors MC1R through MC5R. MC1R activation on melanocytes drives melanin production and tanning; central MC3R/MC4R activation drives erectile response, libido, and appetite suppression. Its non-selectivity is exactly why it produces such a wide, unpredictable effect spectrum.
Non-selective ancestor vs. selective descendant
PT-141 (bremelanotide) was engineered as a more selective MC3R/MC4R agonist and is the only melanocortin peptide to clear Phase III and FDA review (Vyleesi, for HSDD in premenopausal women). MT-II, by contrast, hits every melanocortin receptor, producing tanning, arousal, nausea, appetite loss, mole darkening, and priapism together. Melanoma risk is documented for MT-II in peer-reviewed case reports and regulator warnings, not for PT-141.
What people get wrong
Often said'It's just a tanning peptide, so it's low-risk.'
ActuallyNon-selective melanocortin activation carries documented priapism risk, mole/nevus changes, and case reports of melanoma; regulators have issued formal warnings against it.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Sold illegally online as tanning injections and nasal sprays; entirely unregulated with no purity or sterility controls.
At a glance
- Parent hormone
- alpha-MSH
- Receptors
- Non-selective MC1R-MC5R
- Nickname
- 'Barbie drug'
- Regulator warnings
- FDA, MHRA, TGA
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Melanotan II. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
- Where we land. We have not taken a position on this yet.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
Melanoma case reports associated with Melanotan II use2000s-2020s
At least four peer-reviewed reports of melanoma emerging during/after MT-II use; causation not proven but flagged by regulators
Early melanocortin ED research (basis for PT-141)1990s-2000s
MT-II's erectile effects observed, prompting development of selective bremelanotide