The claimEvidence B · meta-analysis
Collagen peptides 'rebuild' your skin/joint collagen
The evidence
Oral peptides are degraded to amino acids in the gut; this is the 'eat pork knuckle to feed your skin' fallacy.
Why the claim spreads
'Eat the thing to become the thing' is intuitive (and wrong about how digestion works); beauty brands market the story hard.
The mechanism, in brief
Collagen is the body's most abundant protein — about 25–30% of total protein. It forms structural scaffolds in skin, bone, cartilage, tendons, ligaments, vessel walls, and sclera.
Sources (1)
- Khatri, M., Naughton, R. J., Clifford, T., Harper, L. D., & Corr, L. (2021). The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review. Amino Acids, 53(10), 1493-1506.