# Research on ingredients after arrival

> Reading list — LumiDerm Skin Clinic — The LumiDerm Skin Clinic reading list covers extracellular NAD in skin cells, retained copper, collagen synthesis and topical skin research.

**Reading list**

Extracellular NAD starts the collection. The skin-layer experiment, collagen paper and topical reviews give its questions company.

## Penetration experiments; cellular production

[Hostynek, Dreher and Maibach’s human skin penetration study](https://pmc.ncbi.nlm.nih.gov/articles/PMC3016279/) supplies the retained-copper measurements. It is the experiment behind the [depot essay](/copper-depot). [Maquart and colleagues’ fibroblast culture paper](https://pubmed.ncbi.nlm.nih.gov/3169264/) supplies the collagen-synthesis finding, including the observation that cell number did not change.

I value their different scales of observation. Prepared skin permits a question about passage and retention; cultured cells permit a question about activity. The afterimage becomes interesting in the space between them.

## The broader skin literature

The [skin-regeneration review](https://pmc.ncbi.nlm.nih.gov/articles/PMC4508379/) gathers findings on supporting material and clinical skin outcomes. The [topical anti-wrinkle review](https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/) makes delivery an explicit concern.

[Aleo and colleagues’ extracellular NAD paper](https://pubmed.ncbi.nlm.nih.gov/11135366/) follows breakdown products around human skin fibroblasts. The [nicotinamide review](https://pubmed.ncbi.nlm.nih.gov/34439563/) considers a separate starting material applied topically to skin. Together, they make chemical identity a much livelier subject than a list of ingredients.

## References

[1] Human skin penetration of a copper tripeptide in vitro as a function of skin layer https://pmc.ncbi.nlm.nih.gov/articles/PMC3016279/
[2] Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ https://pubmed.ncbi.nlm.nih.gov/3169264/
[3] GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration https://pmc.ncbi.nlm.nih.gov/articles/PMC4508379/
[4] Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective https://pmc.ncbi.nlm.nih.gov/articles/PMC11830136/
[5] Metabolic fate of extracellular NAD in human skin fibroblasts. https://pubmed.ncbi.nlm.nih.gov/11135366/
[6] Mechanistic Basis and Clinical Evidence for the Applications of Nicotinamide (Niacinamide) to Control Skin Aging and Pigmentation. https://pubmed.ncbi.nlm.nih.gov/34439563/

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LumiDerm Skin Clinic is my notebook of published research on ingredients’ chemical afterlives; it is not a business and offers no medical advice.