GHK-Cu in the cream studies
The collagen percentages deserve their full description. A finished body lotion deserves a comparison of its own.
Women with increased collagen production
The skin-regeneration review reports increased collagen production in 70% of women treated with topical GHK-Cu, compared with 50% for vitamin C and 40% for retinoic acid. These are the proportions reported for women showing an increase. They describe how many responded on that measure.
| Topical treatment in the reviewed comparison | Women with increased collagen production |
|---|---|
| GHK-Cu | 70% |
| Vitamin C | 50% |
| Retinoic acid | 40% |
The denominator is easy to lose when these figures are compressed into a larger claim. A statement that 70% showed an increase leaves the size of each increase unstated. Calling it a 70% increase in collagen would replace the reported outcome with a different one.
The later topical GHK review also reports the 70%, 50% and 40% comparison, describing the endpoint as increased procollagen synthesis. Procollagen is the precursor involved in collagen production. I read the endpoint wording carefully rather than treating the repeated numbers as a second set of newly measured results.
A review assembles earlier work. Repetition across reviews can help locate a finding, but it does not by itself add an experiment. My enthusiasm would grow more from a well-described additional trial than from another appearance of those memorable percentages.
The result is worth considering in its actual form, alongside the cell-culture experiment. Declaring a winner among the ingredients from this comparison alone asks too much of this result. The stated measure concerns increased collagen production in the reviewed work; a broad ranking of all their cosmetic uses would require more.
Laxity, fine lines and skin density
The skin-regeneration review describes placebo-controlled improvements in skin laxity, clarity, fine lines, wrinkle depth and density. Here the literature finally gets close to the cosmetic object in the name. It concerns assessed skin outcomes, rather than the peptide's behaviour in an isolated cell experiment.
Still, that list contains several questions. Laxity asks about one aspect of skin, wrinkle depth another, density another. I prefer a description that names the outcome and lets it stand. A broad word such as rejuvenation loses the useful distinctions among them.
The reported results give topical research substance. They do not furnish a result for every formulation carrying the same ingredient name. For the body lotion itself, the interesting question becomes: which of these outcomes would change when that finished preparation is tested, and what would happen with the corresponding base? That question follows from the delivery problem the topical review describes.
A comparison for the whole body lotion
My ideal next experiment would test the finished lotion against its own base, on the body skin the claim concerns, with the outcome chosen in advance. This is a proposed study question. It would connect the topical findings to the actual object named on this page.
A result like that would need a formulation description precise enough to identify the preparation tested. The delivery review's emphasis on poor permeability and enhancement strategies is the reason for that insistence. Changing the preparation can change the question being tested.
Until there is an appropriate result to discuss, I give the existing findings credit for what they address: collagen synthesis in culture and reported topical skin outcomes. They make GHK-Cu interesting. The cream base remains an equally interesting part of the unfinished body-lotion question.