Collagen Type I

Collagen Type I is the most abundant protein in the human body and the predominant structural collagen in skin, bone, tendon, ligament, and cornea. It forms the primary scaffold of the dermis, providing tensile strength and supporting fibroblast attachment. As a dietary supplement, it is consumed as hydrolyzed collagen (collagen peptides) with molecular weights below 6 kDa for improved gastrointestinal absorption and systemic delivery.

Oral hydrolyzed Type I collagen is digested into collagen-specific dipeptides and tripeptides (notably Pro-Hyp and Gly-Pro-Hyp), which circulate in plasma and accumulate in skin, joints, and bone tissue. These fragments stimulate fibroblasts to produce new collagen and hyaluronic acid via activation of anabolic pathways including mTOR and MAPK. In skin, rising circulating hydroxyproline signals the dermis that collagen is being turned over, triggering synthesis. In bone, collagen peptides promote osteoblast activity and support mineralization. In tendons, they support collagenous matrix remodeling when combined with loading exercise.

A systematic review of Type I collagen hydrolysate found improvements in skin elasticity, hydration, and wrinkle reduction across multiple RCTs. Meta-analyses confirm significant improvement in skin hydration and elasticity with 2.5–10 g/day supplementation. Tendon studies show benefits when collagen is combined with resistance training. Bone density outcomes are mixed but favorable in some subpopulations. Overall evidence quality is moderate; industry-funded studies are common.

Peptides commonly paired with Collagen Type I for synergistic effects.