What did @greta.div actually say?
The creator argues that MT1 (afamelanotide) is the safer long-term choice for tanning because it only activates MC1 receptors, while MT2 (melanotan II) also hits brain receptors tied to libido and appetite. Her bottom line: use MT2 for a quick vacation tan, but expect side effects, and stick to MT1 if you want something less disruptive to your hormonal system.
She also notes that MT1 is medically prescribed, mentions MT2 may be in trials for sexual dysfunction, and flags specific MT2 side effects including headaches, blood pressure changes, and appetite suppression. That is a reasonably structured comparison for a TikTok video, and she gets more right than wrong. But there are real errors worth correcting before you inject anything.
Does the science back this up?
Partially, yes. The receptor selectivity argument is the strongest part of her case and it holds up. Afamelanotide is a selective MC1 agonist, and that selectivity is well-documented in the literature. Melanotan II is a non-selective melanocortin agonist that activates MC1, MC3, MC4, and MC5 receptors.
MC4 receptor activation is the relevant one here. MC4 is expressed in the hypothalamus and is linked to both sexual arousal and appetite regulation. This is why melanotan II produces spontaneous erections in male subjects and appetite suppression, effects documented in early Dorr et al. (1996, Journal of Clinical Oncology) work on afamelanotide and subsequent MT2 human trials. Wessells et al. (2000, Journal of Urology) confirmed intranasal MT2 produced erections in men with psychogenic erectile dysfunction, which is likely the trial she is half-remembering. She is correct that those receptor-mediated side effects are real and distinguishable from MT1's profile.
What did they get wrong (or right)?
The disease name needs a correction. She calls it "earthythropietic protoporothirea," which is a phonetic guess at erythropoietic protoporphyria (EPP). That is forgivable on a TikTok. The condition itself is accurately described as a severe photosensitivity disorder, not simply being "allergic to the sun or really pale." EPP involves a specific enzyme deficiency causing painful phototoxic reactions. That distinction matters clinically.
Her framing of MT2 as essentially "like Viagra" for women is where she goes off track. MC4 activation in women does affect arousal pathways, but the mechanism is different from PDE5 inhibition, which is how sildenafil works. Bremelanotide (PT-141), an MT2 analog, was FDA-approved in 2019 under the name Vyleesi specifically for hypoactive sexual desire disorder in premenopausal women. So if anything, MT2's sexual effects are arguably more relevant to women than she realizes, not less. Dismissing it with "I'm a girl" undersells the pharmacology.
- Receptor selectivity claim: accurate
- EPP description: mostly accurate but oversimplified
- MT2 trials for sexual dysfunction: accurate, though the drug is already approved as bremelanotide
- Side effect profile comparison: mostly accurate
- "MT2 is like Viagra" framing: misleading
What should you actually know?
Neither peptide is approved for cosmetic tanning in the US, UK, or EU. Afamelanotide is FDA-approved only for EPP under the brand name Scenesse. Melanotan II has no regulatory approval anywhere for any indication. Bremelanotide (the MT2 analog) is FDA-approved for HSDD but is not the same compound being sold as "MT2" in gray-market peptide supply chains.
Compounded or research-grade versions of these peptides carry significant unknowns around purity, dosing accuracy, and sterility. Blood pressure changes from MT2 are not minor. Clinically documented effects include nausea, facial flushing, and transient hypotension (Dorr et al., 1996). The appetite suppression she mentions is real and mediated through MC4, the same receptor implicated in MC4R mutation studies on human obesity (Farooqi et al., 2003, Science).
If you are considering either peptide, this is a conversation for a licensed provider who can assess your full health picture, not a TikTok comment section.