Melanotan peptides: separating tanning claims from clinical fact

What did @kimconstableofficial actually say?

The creator compared two melanocortin-stimulating peptides: afamelanotide (MT1) and melanotan II (MT2). The core argument is that MT1 "requires UV exposure to activate it" and produces a slower, more natural-looking tan, while MT2 is "far more potent and far more pharmacologically active," producing faster pigmentation changes alongside systemic effects including increased libido and appetite suppression.

She also flagged that MT2 can cause "darkening of moles, freckles and existing pigmentation" but suggested this typically fades when the tan fades. The framing throughout is comparative and relatively measured, stopping short of recommending doses or stacking protocols.

Does the science back this up?

Partially, yes. The pharmacological distinction between MT1 and MT2 is well-supported, but some of the mechanistic details are simplified to the point of being misleading.

Afamelanotide (the synthetic analogue marketed as Scenesse) does work by binding selectively to the MC1R receptor and has a documented dependency on baseline UV for its full photoprotective and pigmentation effects in fair-skinned individuals. Wachsman et al. (2009, Photochemistry and Photobiology) confirmed that MC1R agonism potentiates UV-induced melanogenesis rather than replacing it entirely. That part checks out.

Melanotan II is a non-selective melanocortin receptor agonist, hitting MC1R, MC3R, MC4R, and MC5R. Its appetite-suppressing and pro-erectile effects come from MC4R activity in the hypothalamus, documented in Wessells et al. (1998, Urology) and confirmed in multiple rodent models. So the libido and appetite suppression claims have a real mechanistic basis.

What the video glosses over is that MT2 is not approved by the FDA or EMA for any indication, and its off-label use carries safety signals that the creator does not mention at all.

What did they get wrong (or right)?

The mole-darkening claim deserves more scrutiny than it got. The creator says darkening of moles "typically tends to fade as the tan fades." That is not a reassuring statement, it is an incomplete one.

MT2-associated mole changes have been flagged as a genuine clinical concern. Hersey et al. (2009, British Journal of Dermatology) documented new melanocytic lesion formation and changes in existing nevi in users of melanotan peptides. The assumption that any darkening is benign and reversible is not well-supported in the literature. Telling an audience that mole darkening "tends to fade" without recommending dermatological monitoring is a meaningful omission.

The creator also describes MT1 as working "with the body's natural biology" in a way that implies safety equivalence with natural tanning. Afamelanotide is a pharmaceutical agent approved for a specific rare photodermatosis (erythropoietic protoporphyria). Its safety profile in healthy individuals seeking cosmetic tanning is not established through controlled trials.

On the positive side, the creator correctly identifies that MT2 has broader systemic receptor activity and does not overstate MT1 as a standalone tanning solution without UV. Those are accurate and often misrepresented points in this space.

What should you actually know?

Neither MT1 nor MT2 is approved for cosmetic tanning in the US, UK, or EU. Afamelanotide (MT1 analogue) holds approval only for erythropoietic protoporphyria. Melanotan II has no approved indication anywhere and is explicitly banned for sale in the UK, Australia, and several EU countries.

The "gradual, controlled, natural-looking" framing applied to MT1 describes its mechanism in a clinical context, not its regulatory status or cosmetic safety profile. These are very different things.

For MT2 specifically, the safety concerns go beyond mole darkening. Reported adverse effects in case literature include nausea, spontaneous erections, hypertension, and rare but serious cardiovascular events. Langan et al. (2020, JAMA Dermatology) reviewed the emerging dermatological harms of unsupervised melanocortin peptide use and recommended against their use outside clinical settings.

If you are considering any melanocortin peptide for any reason, that conversation belongs with a board-certified dermatologist or endocrinologist, not a biohacking group, regardless of how well-intentioned the host is.