What Is Collagen?
Collagen is the most abundant protein in the human body, comprising roughly 75–80% of the dry weight of skin's dermis. It is a fibrous structural protein produced by fibroblasts, organised into triple-helix chains that provide tensile strength, resilience, and the scaffolding on which the skin's architecture depends. Type I collagen is dominant in skin, with Type III also present in significant amounts — particularly in younger skin.
Collagen and Ageing
From approximately the late twenties, fibroblasts produce collagen at a declining rate — roughly 1% less per year. Simultaneously, existing collagen fibres undergo glycation, cross-linking, and fragmentation. UV radiation dramatically accelerates this degradation by activating matrix metalloproteinases (MMPs) — enzymes that degrade collagen fibres — making daily SPF the single most important anti-ageing intervention.
What Stimulates Collagen Production?
Retinoids (tretinoin, retinol) are the most evidence-backed topical collagen stimulators — they directly upregulate collagen gene expression and inhibit MMP activity. Vitamin C is a necessary cofactor for collagen synthesis (hydroxylation of proline and lysine residues). Peptides and growth factors show supportive evidence. Energy-based treatments (radiofrequency, laser, microneedling) stimulate collagen remodelling in the dermis.
On oral collagen: Hydrolysed collagen peptides in supplement form show emerging evidence for modestly increasing dermal collagen density. However, effect sizes are smaller than topical retinoids combined with daily SPF.
See Collagen & Elastin Science and Retinoids.