Mechanism

Collagen

Primary structural protein of the dermis; declines and fragments with age and UV exposure.

Review

What it is

Type I and III collagen form the dermal scaffold that gives skin its firmness and resilience.

UV exposure activates matrix metalloproteinases (MMPs) that cleave collagen, while age slows new synthesis. The net effect is gradual structural change.

Why it matters

Collagen biology is the most-discussed scaffold in skin aging conversations.

Related mechanisms

PhysiologyGuideline

UV-Induced Photoaging

Cumulative UVA/UVB damage that drives oxidative stress, MMP activation, and DNA changes.

PhysiologyReview

Oxidative Stress

Imbalance between reactive oxygen species and antioxidant defense; a driver of structural damage.

Ingredient axes

Ingredients that interact with this step

retinoidGuideline

Retinoids

Keratinization / sebaceous axis

Vitamin A-derived agents that normalize follicular keratinization and modulate sebaceous activity.

anti inflammatoryClinical

Vitamin C

Antioxidant axis

L-ascorbic acid and derivatives — antioxidants associated with photoaging-related care.

anti inflammatoryMechanistic

Peptides

Collagen support axis

Short amino acid sequences associated with signaling, carrier, or structural roles in skin.

barrierGuideline

Sunscreen

Photoprotection axis

UV filters that reduce cumulative UVA/UVB exposure — the most evidence-supported aging-related axis.