The Structural Framework of Your Skin
The dermis is essentially a matrix of structural proteins suspended in a gel-like ground substance. Two proteins dominate this matrix and are directly responsible for what we call youthful skin: collagen and elastin.
Collagen: The Tensile Strength Protein
Collagen accounts for approximately 70% of the dermis by dry weight and provides skin with its tensile strength — the resistance to stretching and tearing. Type I collagen is the most abundant, forming long, rope-like fibrils. Type III collagen provides more flexible support and is predominant in younger skin.
Collagen is synthesised by fibroblasts — the dermis's workhorse cells. Production peaks in the mid-20s and then declines at approximately 1% per year thereafter, accelerated significantly by UV radiation and smoking.
UV and collagen: A single bout of severe sunburn can break down more collagen than 6 months of normal ageing. UVA (which penetrates glass) is particularly damaging — it generates metalloproteinases (MMPs) that actively degrade existing collagen fibres.
Elastin: The Recoil Protein
Elastin fibres form a network woven between collagen fibres, giving skin its ability to stretch and spring back. Unlike collagen, elastin is produced almost entirely in the neonatal period and early childhood — adult fibroblasts produce very little new elastin. What you have is largely what you'll keep.
Elastin degradation (elastosis) is a key driver of wrinkle formation, particularly the coarser, deeper wrinkles associated with advanced photoageing.
What Actually Works to Stimulate Collagen
| Approach | Evidence Level | Mechanism |
|---|---|---|
| Tretinoin / Retinoids | High (RCT-backed) | Directly stimulates fibroblast collagen synthesis via RAR receptors |
| Vitamin C (L-Ascorbic Acid) | High | Essential cofactor for collagen cross-linking; cannot proceed without it |
| Peptides (matrikines) | Moderate | Signal peptides mimic collagen fragments, trigger synthesis response |
| Microneedling | High | Controlled injury response triggers TGF-β1-mediated collagen remodelling |
| "Collagen" topicals | None for new synthesis | Molecules too large to penetrate; only surface moisturisation |
| SPF (daily, broad-spectrum) | Very high (prevention) | Prevents UV-triggered MMP activation — the single most effective collagen-preservation tool |
For how retinoids stimulate fibroblasts, see our Retinoids guide. For the Vitamin C collagen connection, visit Antioxidants & Vitamin C.