Hydrolyzed protein
Collagen peptides
Moderate evidenceCollagen broken into small peptides. Popular, but not a complete protein.
What it is
Collagen peptides are collagen that has been broken down (hydrolyzed) into small chains. They are rich in glycine, proline, and hydroxyproline but lack the essential amino acid tryptophan.
Food sources
Bone brothGelatinSkin-on poultry and fish
What the research shows
- Human trials suggest possible benefits for skin elasticity and joint comfort; study quality varies.
- Because it is an incomplete protein, collagen is not a substitute for complete protein sources for muscle building.
- Some research pairs collagen or gelatin with vitamin C before exercise to support tendon and ligament collagen.
Read the published research on PubMed →
Food first: most people get what they need from a varied diet with enough total protein. Talk to a provider or registered dietitian before adding a supplement, especially if you take medication or have a health condition.