What did @ethandoespep1 actually say?
Ethan recommended three peptides to stack with "reddit" (almost certainly retatrutide, a GLP-1/GIP/glucagon triple agonist). His picks: retatrutide for fat loss, growth hormone support, and sleep; GHK-Cu copper peptide for skin appearance; and melanotan II (MT2) over melanotan I (MT1) for tanning, with a nod to MT2's pro-erectile side effect, which he says he "doesn't mind." He also briefly addressed freckle growth as a known MT2 complaint.
This is a personal testimonial dressed up as a protocol recommendation. He's not citing studies. He's describing what he likes and how it makes him feel or look. That's fine as far as it goes, but 14,000 viewers may not all hear it that way.
Does the science back this up?
Partially, and unevenly across the three compounds. Retatrutide's metabolic data is genuinely strong. GHK-Cu's skin evidence is real but modest. Melanotan II's evidence is a mess of small studies and safety signals that a 60-second TikTok cannot responsibly summarize.
Retatrutide (LY3437943) showed up to 24.2% body weight reduction in Eli Lilly's Phase 2 trial published in the New England Journal of Medicine (Jastreboff et al., 2023). That visceral fat reduction Ethan mentions? Plausible. Growth hormone secretagogue activity? Retatrutide does not directly stimulate GH, so his claim that "your growth hormones up" is not supported by the mechanism or the Phase 2 data. GHK-Cu has legitimate peer-reviewed work showing collagen stimulation and antioxidant effects in vitro (Pickart et al., 2015, Journal of Aging Research), though controlled human RCTs are sparse. Melanotan II activates MC1R and MC4R receptors, which explains tanning and erection, but the safety data is alarming enough that the EMA and FDA have both flagged it as unauthorized and potentially dangerous.
What did they get wrong (or right)?
He got the retatrutide fat loss story mostly right. Where he stumbled is claiming it raises growth hormone. That is not what the compound does. He also glossed over the significant risk profile of MT2 in a way that borders on irresponsible. The freckle comment is accurate but downplayed.
On GHK-Cu, calling it something that "clears up my skin" and gives a "glowy look" is a light but defensible claim, given the peptide's known role in fibroblast activation and collagen synthesis. Giving him partial credit there. But the retatrutide-raises-GH claim is flat wrong. Retatrutide is a triple agonist at GLP-1, GIP, and glucagon receptors. None of those pathways directly stimulate GH secretion. He may be confusing it with a GHRP or conflating improved sleep quality with GH release, which is speculative at best. On MT2, the "side effect" he likes is penile erection, a known MC4R-mediated effect. He is correct that MT1 carries a lower freckle-growth risk and is considered somewhat safer in the literature, but neither compound is approved for human cosmetic use.
What should you actually know?
These three compounds are not equivalent risks. Retatrutide is in late-stage trials with real human data. GHK-Cu is low-risk with modest evidence. Melanotan II is a different story entirely, and anyone self-administering it from unregulated sources is taking on serious unknowns.
Retatrutide is not commercially available outside clinical trials as of 2024. Anyone sourcing it is getting a research chemical of unverified purity. GHK-Cu has a reasonable safety profile in topical and low-dose injectable forms, but the clinical evidence for dramatic visible skin changes in healthy adults is thinner than TikTok makes it sound. Melanotan II has been linked to melanoma progression concerns in case reports (Hjuler et al., 2015, JAMA Dermatology), blood pressure changes, nausea, and spontaneous erections in public, which is not a neutral side effect to gloss over. The European Medicines Agency explicitly warned against MT1 and MT2 products in 2014. Taking peptide stacking advice from a TikTok with no dosing context, no baseline bloodwork, and no physician oversight is a genuinely risky move, regardless of how casual the creator makes it sound.