08/31/2026
Glycine, proline, and hydroxyproline are three amino acids that play a central role in the structure and stability of collagen, the protein that provides strength and elasticity to the skin, bones, joints, and connective tissues.
Glycine is the smallest amino acid and fits into the center of collagen’s tightly packed triple-helix structure, while proline helps the collagen chains bend and form their characteristic shape.
Hydroxyproline, which is produced from proline through a vitamin C-dependent process, helps stabilize the collagen triple helix through hydrogen bonding.
Together, these three amino acids make up a large proportion of collagen’s amino-acid composition and are therefore particularly important for collagen formation and maintenance.
A recent human study published in npj Aging investigated these amino acids in a 3:1:1 ratio of glycine, proline, and hydroxyproline and reported promising effects on healthy aging and skin health. After six months of supplementation, participants showed an average 1.4-year reduction in estimated biological age, while measures of skin hydration, texture, wrinkle depth, and elasticity reportedly improved by approximately 4–6% within one to three months.
Preclinical studies also reported benefits related to lifespan and physical function, although animal findings cannot be directly applied to humans.
Researchers propose that the combination may not simply provide raw materials for collagen production but may also influence cellular signaling involved in the production of collagen, hyaluronic acid, and elastin and the regulation of collagen breakdown.
