Copper Peptides and the Topical Delivery Question

What GHK-Cu is

GHK is a naturally occurring tripeptide — glycyl-L-histidyl-L-lysine — first isolated from human plasma in the 1970s. It binds copper with high affinity, and the copper complex GHK-Cu is the form studied in skin biology.

Plasma levels decline substantially with age, which is the origin of the ageing-related interest. The peptide has documented roles in wound repair signalling and extracellular matrix remodelling.

What the research supports

The strongest work concerns skin: collagen synthesis, wound healing models, and effects on matrix metalloproteinases and their inhibitors. There is a reasonable body of in vitro and animal work plus some human cosmetic studies on skin appearance.

Hair is weaker. The mechanistic rationale — follicle environment, perifollicular vasculature, growth-phase signalling — is plausible, and the human evidence is thin compared with compounds that have been through proper trials. Products in this category are generally positioned cosmetically, around appearance rather than regrowth, and that positioning is the honest one.

The delivery question

At roughly 340 daltons, GHK-Cu is small by peptide standards and closer to the transdermal rule-of-thumb range than most. Even so, it is hydrophilic and charged, and the stratum corneum still resists it.

For scalp products the follicular route matters: hair follicles are effectively channels through the barrier, and follicular penetration is a recognised pathway for topically applied compounds. That is a real mechanism, not a marketing construct.

Why the base matters so much

Copper peptide stability is pH-sensitive, and the complex can dissociate or be displaced in a poorly designed formulation. Copper is also a redox-active metal, so pairing GHK-Cu with strong antioxidants such as high-dose vitamin C or with certain acids can be chemically counterproductive.

Some products use dimethyl sulfoxide as a permeation enhancer. It works and it carries its own considerations — skin irritation, a characteristic taste and odour effect, and the fact that it carries whatever else is dissolved in it through the barrier too.

Realistic expectations

Effects on appearance in this category develop over months, not weeks, because they depend on the hair growth cycle. Assessment before eight to twelve weeks of consistent use is premature.

Cosmetic products are regulated as cosmetics. They may make appearance claims and may not make drug claims. A product observing that boundary is behaving correctly, not being evasive.