BPC-157 and peptide stacks: separating gym lore from actual data

What did @forgedbyolsen actually say?

The creator says GHK-Cu was their primary reason for starting peptide therapy, specifically to address loose skin after losing 55 pounds, with a prior 80-90 pound loss a decade earlier. They claim it works by "increasing collagen production" and that it has "done a good job" so far. They recommend subcutaneous injection into fatty tissue around the navel and suggest pairing it with collagen peptide supplements. They also plug a vendor called Modern Aminos with a discount code.

To be clear about what they are not saying: they are not claiming a dramatic overnight fix. They acknowledge they may still need surgery eventually. That level of hedging is actually more honest than a lot of peptide content on TikTok.

Does the science back this up?

Partially, yes. GHK-Cu (glycyl-L-histidyl-L-lysine copper) has legitimate preclinical evidence for collagen stimulation, but almost none of it comes from humans testing it for post-weight-loss loose skin specifically. That gap matters a lot.

GHK-Cu has been studied for decades as a skin-active compound. Pickart and colleagues, going back to work published in journals including the Journal of Biomaterials Science (Pickart, 2008), documented its role in activating collagen and elastin synthesis in fibroblasts. A 2015 review by Pickart and Margolina in Cosmetics confirmed GHK-Cu upregulates collagen I, elastin, and glycosaminoglycans in cell culture and rodent wound models. The problem is these are mostly in vitro and topical studies. Systemic subcutaneous use for loose skin in humans after weight loss has not been studied in any peer-reviewed trial.

Oral collagen peptides have slightly better human data. A 2019 randomized controlled trial by Proksch et al. in Skin Pharmacology and Physiology found that collagen peptide supplementation improved skin elasticity in women, though the subjects were healthy adults, not post-bariatric or major weight loss patients.

What did they get wrong (or right)?

The collagen production mechanism the creator describes is directionally correct based on preclinical data. GHK-Cu does appear to signal fibroblast activity and collagen gene expression. That part is not invented. Give credit where it is due.

What is misleading is the implied clinical certainty. Saying GHK-Cu is "highly effective" for loose skin after significant weight loss goes beyond what the evidence actually supports in humans. It may help. There is a plausible biological mechanism. But "highly effective" suggests a level of clinical validation that does not exist for this specific application.

The injection site guidance, aiming for subcutaneous fatty tissue around the navel, is the typical self-administration approach in the peptide community, but there is no standardized dosing protocol from clinical trials for this compound injected systemically. The creator does not mention dose, which is actually better than most content out there, but the overall framing treats an unproven protocol as established practice.

What should you actually know?

If you have significant loose skin from weight loss, the honest conversation is this: peptides are not a replacement for surgical consultation, and no compound has been proven in clinical trials to reverse loose skin in that context. GHK-Cu is genuinely interesting scientifically, and it is not snake oil, but interesting mechanisms in cell cultures do not equal proven outcomes in your body after major fat loss.

A few things worth knowing:

• Loose skin after major weight loss has a structural component involving stretched dermis and reduced elastin that no current non-surgical intervention has reliably reversed in high-quality human trials.
• GHK-Cu is not FDA-approved for any injectable indication. It is available as a research compound. Quality, purity, and dosing consistency vary significantly between suppliers.
• Collagen supplements have the best human evidence in this general space, though studies are not specific to post-weight-loss skin laxity.
• Anyone considering self-injecting any peptide should consult a licensed medical provider. A telehealth prescriber who specializes in peptide therapy can order appropriate labs and supervise protocols.
• Vendor discount codes in peptide TikToks are a financial relationship worth disclosing. The creator did not make that explicit.