More evidence than most wellness trends for joints and skin — less for the bigger 'gut healing' claims.
Collagen supplements and bone broth are heavily marketed for joint, skin and gut health, often with inflammation reduction claims attached — worth separating what's plausible from what's proven.
Some clinical studies on collagen peptide supplements have found modest improvements in joint pain and skin elasticity — a real, if modest, evidence base exists here, more than for many wellness trends covered on this site.
Broader claims about bone broth specifically "healing the gut lining" or providing uniquely bioavailable collagen are less well supported — collagen is broken down into individual amino acids during digestion like any other protein, and there's limited evidence it's reassembled specifically into joint or gut tissue as the marketing sometimes implies.
Bone broth is a reasonable, minimally processed food that can fit well into a low-inflammatory-load diet — just not for the specific "healing" mechanism often claimed. Collagen supplements have a modest, real evidence base for joint and skin outcomes specifically, distinct from general inflammation claims.