What did @hairwellnessbymarissa actually say?
Marissa made a broadly framed argument: GHK-Cu is a copper peptide your body produces naturally, levels drop with age, and that decline connects to collagen production, tissue repair, inflammation, and hair health. Her core line was that "healthy hair is built at the cellular level," not from topical products. She stopped short of saying GHK-Cu treats hair loss directly, which matters. What she described was more of a biological mechanism story than a clinical claim, and that framing is actually worth paying attention to.
She did not recommend a dose, name a protocol, or tell viewers to inject anything. That restraint makes this video harder to dismiss than most peptide content on TikTok. The question is whether the mechanism she described holds up when you look at the actual research.
Does the science back this up?
Mostly, yes, with real caveats. GHK-Cu is not some fringe wellness invention. It was first isolated from human plasma by Loren Pickart in 1973, and decades of subsequent research have confirmed it does influence collagen synthesis, wound healing, and anti-inflammatory signaling. The part that gets murky is the hair-specific evidence.
A 1993 study by Uno and Kurata published in the Journal of Investigative Dermatology found that topical GHK-Cu stimulated hair follicle size and hair shaft diameter in a primate model. Rushton et al. have published on copper peptides and follicle health in humans, though sample sizes in those trials were small. More recently, work published by Pickart and Margolina (2018) in the journal Biomolecules summarized GHK-Cu's role in gene expression regulation, showing it upregulates genes tied to tissue remodeling and downregulates pro-inflammatory pathways. That is real science. What is not well established is whether systemic GHK-Cu administration meaningfully raises follicle-level concentrations enough to change hair outcomes in humans. Most of the compelling data is still from topical applications or in vitro work.
What did they get wrong (or right)?
She got the foundational biology right. GHK-Cu does decline with age. A 2012 paper by Pickart in the International Journal of Molecular Sciences documented measurable decreases in circulating GHK-Cu from roughly 200 ng/mL in young adults to near baseline in older populations. The connection to collagen and tissue repair is well supported. Credit where it is due.
Where she oversimplifies: the leap from "GHK-Cu supports collagen production" to "your hair thinning is connected to GHK-Cu decline" is not directly proven in clinical trials. Hair loss is multifactorial. Attributing it primarily to a peptide decline skips over DHT sensitivity, thyroid function, iron status, and genetics. Saying "if your body is inflamed, your hair feels thinner" is plausible but presented with more certainty than the evidence warrants.
She also never tells viewers what they are supposed to do with this information, which is either responsible or strategically vague depending on how charitable you want to be. "Follow along because that's what I do" is not clinical guidance, but it is building toward a commercial relationship.
What should you actually know?
GHK-Cu is one of the more legitimately researched peptides in the anti-aging space. That does not mean it is proven to regrow hair or reverse age-related hair thinning in humans at a clinical level. The most honest summary of the evidence is this: the mechanisms Marissa described are real, the human trial data for hair specifically is thin, and the delivery method matters enormously. Topical GHK-Cu has the most evidence for scalp applications. Systemic peptide therapy for hair is being explored but is not standard of care.
If you are experiencing hair loss, a dermatologist or trichologist should be your first call, not a TikTok peptide guide. Conditions like androgenetic alopecia, alopecia areata, or telogen effluvium have established diagnostics and treatments. GHK-Cu is not a replacement for that workup. It may be an interesting adjunct conversation to have with a qualified provider, but "the future of beauty from the inside out" is a marketing frame, not a clinical one.