What Is Collagen — And Why Should You Care?

Collagen is the scaffolding beneath your skin. It keeps it firm, plump, and resilient — and from your mid-20s, your body starts producing less of it every year.

By your 30s, the effects become visible: fine lines, loss of elasticity, a complexion that feels less lit from within. Understanding collagen isn't vanity. It's skin literacy.

So, what exactly is collagen?

Collagen is a structural protein that makes up approximately 75–80% of your skin's dry weight. It forms a dense network of fibres in the dermis — the deeper layer of your skin — providing the structure, strength and elasticity that keeps skin looking youthful.

Think of it as the mattress springs beneath the surface. When those springs are strong and tightly wound, skin sits high and firm. As collagen degrades, those springs loosen — and the surface above begins to sag.

Why does collagen decline?

Collagen production begins declining at roughly 1% per year from your mid-20s. By your 40s, you've lost a significant portion of your skin's structural integrity. Several factors accelerate this:

• UV exposure — the single biggest external cause of collagen degradation
• Inflammation — from diet, stress, pollution and lifestyle
• Hormonal changes — particularly the drop in oestrogen during perimenopause
• Glycation — excess sugar in the diet that literally stiffens and damages collagen fibres
• Smoking — restricts blood flow and generates collagen-destroying free radicals

The three types of collagen in your skin

Not all collagen is the same. In skin, the three main types are:

• Type I — the most abundant, responsible for skin strength and smoothness
• Type III — found alongside Type I, contributes to elasticity and wound healing
• Type IV — forms a mesh-like layer that supports the skin's barrier function

When people talk about "collagen loss" in skincare, they're primarily referring to the gradual breakdown of Type I and Type III.

Can you rebuild collagen?

Yes — to a degree. While you can't fully reverse natural collagen loss, you can significantly slow it and stimulate new production. Learn more in our guide on the daily habits that silently destroy your collagen, and what to look for in a collagen skincare product.

• Topical ingredients that signal fibroblasts (your collagen-producing cells) to work harder
• Protecting existing collagen from UV and environmental damage
• Nutritional support — particularly Vitamin C, which is essential for collagen synthesis. Read more in our post on nutrition and skin health.
• Consistent skincare that supports your skin barrier and reduces inflammation

Understanding what collagen is — and what depletes it — is the first step toward skin that stays resilient, longer. See how skin changes across each decade in our post How Your Skin Changes Every Decade.