# Procollagen responses in treated subjects

> Topical findings | Advanced Laser Skin Clinic — At Advanced Laser Skin Clinic, reported procollagen-response percentages retain their meaning as proportions of subjects, with delivery still in view.

**The human synthesis finding**

This percentage describes people with a recorded response. I want that subject left visible.

## The reported proportions

A [review of topical GHK reports increased procollagen synthesis in 70% of GHK-Cu-treated subjects, versus 50% for vitamin C and 40% for retinoic acid](https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/). Procollagen is a precursor in collagen production. These are proportions of subjects with an increase in synthesis.

I appreciate a human measurement with a biological subject. But the sentence becomes a different claim if the proportion of people responding is retold as the size of their improvement. The reported proportions provide no basis for calling this a 70% reduction in wrinkles.

Those distinctions can sound fussy until a number starts travelling. A percentage needs something to be a percentage of. Here that something is the group of treated subjects, classified by a synthesis response.

## Permeability and modification

The [review also identifies poor stratum-corneum permeability as a central challenge for topical GHK](https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/). It evaluates palmitoylation, a chemical modification, and microneedle pretreatment as delivery strategies. The topic has more moving parts than a peptide name suggests.

Preparation and outcome both deserve some of that excitement. I favour connecting the human outcome as closely as possible to the substance that reached the relevant tissue. That is a request for a more complete explanation, not a reason to discard the finding.

![An adult stands side-on at a broad hallway mirror in natural light, with their face seen only obliquely.](images/ordinary-mirror.webp)

*An imagined everyday scene. The person illustrates attention to appearance and represents no study participant, treatment outcome or endorsement.*

## A separate human endpoint

The [hair-count trial](/hair-counts) gives another human endpoint and another preparation: a combination of GHK with 5-aminolevulinic acid. The count concerns hair, and the preparation contains both ingredients. I leave those differences standing, even when a peptide name is shared.

These papers give my curiosity both room and boundaries. A broad molecular signal can occupy the imagination while a modestly framed human finding gives it a much more exact question to answer.

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At Advanced Laser Skin Clinic, I pursue the specifics in published research about GHK and skin; this publication has no treatment business and offers no medical advice.