What GHK-Cu is
GHK is a tripeptide: three amino acids, glycine, histidine and lysine. It binds copper tightly, and the pair, GHK-Cu, is a molecule your body makes. Loren Pickart first isolated it from human plasma in 1973 while studying why tissue from older donors behaved like tissue from younger donors when exposed to young plasma.
In the lab, GHK-Cu has been shown to influence the genes and proteins involved in the skin's extracellular matrix, the scaffolding of collagen, elastin and glycosaminoglycans that gives skin its structure. That mechanism work is why formulators reach for it. The cosmetic case rests on the facial studies below.
Copper on its own is a metal. Bound to GHK it is a signal.
Why it declines
Plasma levels of GHK-Cu fall with age. The figures most often cited from Pickart's work are about 200 ng/mL at age 20 and about 80 ng/mL by 60, a drop of roughly 60%. Skin is one of the tissues where that shows.
Approximate plasma GHK-Cu by age, after Pickart. Illustrative curve between the two published points.
The skin studies
These are the human facial studies that matter for a cosmetic. Sizes are small by drug-trial standards, which is normal for skincare, and worth knowing.
| Study | Design | What was measured | Result |
|---|---|---|---|
| Leyden 2002 | 67 women, 12 weeks, GHK-Cu cream vs placebo, facial | Fine lines, skin firmness, clarity, by clinical grading and instruments | Improved appearance of fine lines and skin firmness and density vs placebo |
| Abdulghani 1998 | 20 women, GHK-Cu cream vs vitamin C and retinoic acid creams, thigh | Collagen production in skin biopsies | Copper peptide cream increased collagen in more subjects than vitamin C or retinoic acid |
| Finkley 2005 | Facial study, GHK-Cu cream, 12 weeks | Photodamage grading, wrinkle depth, skin thickness (ultrasound) | Reduced appearance of wrinkles and photodamage, increased skin density |
| Pickart 2018 (review) | Review of GHK-Cu skin, hair and wound literature | Mechanism and gene-expression studies | Summarizes matrix-remodeling and antioxidant actions seen in laboratory work |
What this supports, in cosmetic language: the appearance of firmer, smoother skin and softer-looking fine lines over about twelve weeks. What it does not support: medical claims. We make none.
Why the serum is blue
Copper(II) bound to the GHK peptide absorbs red light and reflects blue, the same chemistry that makes copper sulfate crystals blue. The intensity of the blue tracks the copper concentration. We add no dye, and we don't dilute: at 2% the serum is distinctly blue in the bottle and dries clear on skin.
A copper peptide serum that is nearly colorless is either very low in copper or using a different copper source. Ask.
What not to mix
GHK-Cu is stable at the skin's own pH, around 5.5, which is where Covell sits. Two things disturb it: strong direct acids, which lower the pH enough to change how the copper is held, and L-ascorbic acid (vitamin C), which can reduce the copper and pull it off the peptide. Use acids and vitamin C at the other end of the day. Retinol, niacinamide, hyaluronic acid, ceramides and sunscreen are all fine alongside it.
References: Pickart L, Thaler MM. Nature New Biol 1973. Leyden J et al., American Academy of Dermatology meeting 2002 (skin care study). Abdulghani AA et al., J Dermatol Res 1998. Finkley MB et al., in Cosmeceuticals and Active Cosmetics 2005. Pickart L, Margolina A. Int J Mol Sci 2018. Study listings are summaries for a cosmetic audience; read the papers for full methods.