The Basics
What Is Collagen?
Collagen is the most abundant protein in the human body, making up approximately 30% of total protein content. It is the primary structural component of skin, bones, tendons, ligaments, cartilage, blood vessels, and the gut lining.
The word “collagen” comes from the Greek kolla (glue) and gen (producing) — literally “glue producer.” This is fitting because collagen is the biological glue that holds your body together. It provides structural integrity, tensile strength, and elasticity to virtually every tissue.
Each collagen molecule consists of three polypeptide chains (alpha chains) wound into a tight triple helix — like a three-stranded rope. This triple helix structure gives collagen extraordinary tensile strength: gram for gram, type I collagen is stronger than steel. The amino acid composition is unique among proteins, with glycine appearing at every third position (Gly-X-Y repeat) and unusually high concentrations of proline and hydroxyproline.
Scientists have identified at least 28 types of collagen, but five types (I through V) account for over 99% of collagen in the human body. Understanding which type does what is the key to targeted supplementation and lifestyle optimization.
Collagen Decline With Age
Starting around age 25, your body produces approximately 1-1.5% less collagen each year. By age 40, you have lost 10-20% of your skin's collagen. By age 60, the loss exceeds 40%. In women, collagen decline accelerates dramatically after menopause — up to 30% of dermal collagen is lost in the first five years post-menopause due to declining estrogen, which stimulates collagen synthesis. This is not just a cosmetic concern: collagen loss affects joint function, bone strength, gut integrity, cardiovascular health, and wound healing capacity.
Age 25
Decline begins (~1%/yr)
Age 40
10-20% total loss
Age 50
25-35% total loss
Age 60+
40%+ total loss
Varani et al., 2006 — American Journal of Pathology; Shuster et al., 1975 — British Journal of Dermatology