Collagen vs Zinc

for skin

Stronger evidence: tie

Stronger effect: tie

Safety: No notable interactions recorded for either.

For skin, the two are evidence-matched; the difference is in effect and safety.

Collagen

grade C low certainty

small improvements in skin elasticity/hydration in industry-funded trials

2.5–10 g/day

Acquired zinc deficiency is deeply involved in the development of skin diseases including acquired acrodermatitis enteropathica, necrolytic migratory erythema, alopecia, and delayed wound healing, and mutations or dysregulation in zinc transporters are associated with skin manifestations.

sources: PMID:00000028 · PMID:29439479