GHK-Cu Peptide Draws Anti-Aging Buzz as 1973 Discovery Faces Thin Human Evidence

Q: Could your vitamin C serum be making your popular GHK-Cu anti-aging product completely useless?

Yes—if your vitamin C serum is the common low-pH form, L-ascorbic acid, using it at the same time as GHK-Cu can significantly reduce the peptide’s effectiveness and may also destabilize the vitamin C. The issue is chemistry. GHK-Cu, a copper peptide used in anti-aging skincare, is most stable around a near-neutral pH. L-ascorbic acid serums usually work at a much lower pH, often below 3.5. That acidic environment can disrupt the copper-peptide complex, while the copper can also speed oxidation of vitamin C. In practical terms, both products may perform worse when layered together immediately. That does not mean GHK-Cu is useless overall. It means timing and formulation matter. Experts generally advise separating them rather than abandoning one. A common approach is vitamin C in the morning for antioxidant protection, then GHK-Cu at night for repair-focused use. If someone insists on using both in one routine, waiting 20 to 30 minutes after vitamin C may reduce interference, though it is still less ideal than separating them by time of day. The warning mainly applies to pure L-ascorbic acid and other highly acidic products such as glycolic, lactic, or salicylic acid. Some vitamin C derivatives, including THD ascorbate or ascorbyl glucoside, are less likely to conflict because they work at a higher pH. Topical GHK-Cu appears generally well tolerated, but injectable or oral versions remain far less studied and warrant much more caution.

3 articles · Updated · USA TODAY · Jun 13

GHK-Cu — a copper peptide first identified in 1973 — is drawing fresh attention in skincare and longevity circles for claims it may support regeneration and reduce visible aging.
Topical use drives much of that interest: early studies suggest it may boost collagen and elastin, aid wound healing and possibly support hair growth with less irritation than retinoids.
Human evidence remains limited, especially beyond creams and serums, with broader claims around brain protection, nerve repair and lung healing still based largely on lab and animal research.
Safety questions center on oral and injectable products sold by wellness clinics and online, where FDA approval for anti-aging use is lacking and dosing, purity and long-term effects remain unclear.
Experts say topical GHK-Cu appears generally safe, but people who are pregnant, take medications or have copper-metabolism disorders such as Wilson’s disease should seek medical advice first.