What collagen actually is
The most abundant structural protein in the body, found in skin, tendons, ligaments, and joints — production naturally declines with age, which is the basis for most collagen supplement marketing.
What the research on skin actually shows
Several studies have found modest improvements in skin elasticity and hydration with consistent collagen supplementation over 8-12 weeks — a genuine, if moderate, effect, not simply marketing fiction.
The joint health angle
Some evidence supports collagen (particularly type II) for joint comfort in people with existing joint issues, though the effect size is generally modest and shouldn't be expected to reverse significant joint damage.
Whether it's actually necessary for most people
The body can synthesize collagen from adequate protein and vitamin C intake through regular food — supplementing directly is a reasonable convenience option, not a requirement for people already eating a balanced, protein-adequate diet.