Does collagen work for skin, joints, or muscle?

Collagen works best for the thing people most want it for - skin - and worst for the thing the experts get asked about most: muscle. Splitting it by target clears up the confusion.

For skin, the case is strongest. Huberman states that ingesting around 15g of collagen daily can improve skin elasticity and appearance (range 5-30g/day for skin thinning), and several randomized trials back skin elasticity, hydration, and wrinkle-depth improvements. The catch every expert adds: pair it with vitamin C, which is a required cofactor for collagen synthesis.

Johnson takes peptides daily specifically for skin and joints.

For joints and connective tissue, it's plausible but thinner. Patrick and Attia's shared source, protein researcher Dr. Luc van Loon, notes collagen peptides may benefit connective tissues like skin, tendons, and cartilage, especially after injury or surgery, while acknowledging the evidence is limited. So it's reasonable around an injury, but not a proven joint cure.

For muscle, this is the myth to kill. All five experts agree collagen is inferior to whey for building muscle because its leucine content - the trigger for muscle-protein synthesis - is too low. Attia goes furthest, calling collagen a low-quality protein with an imbalanced amino-acid profile that doesn't outperform whey or casein for connective-tissue synthesis either, even though he concedes a role as a glycine and proline source for recovery.

Hyman's angle is preservation: cortisol, sugar, and UV break collagen down, so protecting it (and getting it from bone broth) matters as much as supplementing. Net: take collagen for skin, optionally around joint recovery, and use whey - not collagen - for muscle.