Detailed definition
Collagen is the principal structural protein in skin, bone, tendon, ligament, and other connective tissue. Type I collagen dominates skin and bone. Skin collagen content declines roughly 1% per year after age 30 in women, with an accelerated phase post-menopause: studies have measured approximately 30% collagen loss in the first 5 years post-FMP. The mechanism involves estrogen withdrawal effects on dermal fibroblast proliferation and matrix metalloproteinase activity. Topical and systemic estrogen replacement modestly improve skin collagen content in randomized trials, although the magnitude is smaller than commonly marketed cosmetic claims suggest. Bone collagen (osteoid matrix) is also affected; reduced collagen quality contributes to fragility independent of mineral content.
Why it matters in menopause
Collagen loss is part of why menopausal women notice skin changes, joint pain, and bone fragility appearing together. HRT modestly addresses all three but is rarely the dominant intervention for any of them in isolation.
Related terms
Sources
External references: Wikipedia.