Liu · Food & function 2019 · In vitro cell culture study · n=?

Collagen peptides promote photoaging skin cell repair by activating the TGF-β/Smad pathway and depressing collagen degradation.

Cited 106 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

In vitro laboratory study on cultured skin fibroblasts

PubMed 31497829 · doi:10.1039/c9fo00610a · record verified 2026-08-29

What was done

Researchers evaluated the cellular repair mechanisms of serum containing collagen peptides collected after oral administration and isolated serum collagen peptide fractions in UVA-damaged skin fibroblasts. They tested effects on cell proliferation, hyaluronic acid secretion, reactive oxygen species scavenging, procollagen synthesis, and degradation pathways involving TGF-beta/Smad, AP-1, MMP-1, and MMP-3, and analyzed active hydroxyproline-containing peptides.

What was found

Serum collagen peptide fractions promoted procollagen synthesis via activation of the TGF-beta/Smad pathway and suppressed collagen degradation by reducing AP-1, MMP-1, and MMP-3 protein expression. They also scavenged reactive oxygen species and preserved endogenous antioxidant defenses. The specific peptides Ile-Hyp and Ala-Hyp-Gly were identified as active drivers of procollagen synthesis via TGF-beta/Smad3. No numerical values or effect sizes were reported in the abstract.

Why it matters

This study identifies specific bioactive peptide metabolites that appear in serum after oral collagen ingestion and outlines their molecular pathways in cellular skin repair.

Limits

This is an in vitro laboratory study, so findings cannot be directly translated to clinical outcomes in humans. The abstract does not report sample sizes, donor species, dosing amounts for the oral administration phase, or quantitative effect sizes.

Cited by