Collagen is ineffective for muscle building due to its very poor amino acid profile, specifically its low content of leucine and essential amino acids (EAAs).

noli's read

Layne Norton's analysis is based on sound biochemical principles: muscle protein synthesis requires an adequate concentration of leucine, which acts as a metabolic switch, and a complete profile of EAAs, which collagen does not provide (Journal of the International Society of Sports Nutrition, meta-analysis on proteins). Collagen is indeed low in leucine and tryptophan, unlike complete proteins such as whey, making it a poor choice for hypertrophy. Where the creator is somewhat definitive is regarding connective tissue: clinical studies (RCT, American Journal of Clinical Nutrition) suggest that specific collagen peptides, combined with exercise, could improve tendon or joint health via cell signaling mechanisms, rather than simple direct incorporation. It is therefore accurate to say that collagen does not build muscle, but it is possible that its benefits for the body are more nuanced than the simple calculation of amino acids. In summary, collagen is not a muscle builder, but it is not necessarily 'trash' for other aspects of physical well-being.

the sources

1. 1Lim MT, Pan BJ, Toh DWK, Sutanto CN, Kim JE 2021
2. 2Tagawa R, Watanabe D, Ito K, et al. 2020
3. 3Rutherfurd SM, Fanning AC, Miller BJ, Moughan PJ 2015