Collagen is a low-quality protein for muscle gain because it lacks essential amino acids like leucine; it does not replace complete protein sources for performance or body composition.

noli's read

Layne Norton’s analysis is firmly grounded in the principles of nutritional biochemistry. It is scientifically established, notably through studies on muscle protein synthesis (MPS), that leucine is the key trigger amino acid for muscle growth, an element absent from the collagen profile (evidence: physiological studies on protein quality). Regarding the skin, meta-analyses and randomized controlled trials (RCTs) indeed suggest modest benefits for elasticity and hydration, confirming the nuance provided by the creator. The term 'low quality' is appropriate in the exclusive context of hypertrophy, as collagen has an incomplete amino acid profile compared to complete animal or plant proteins. There is no exaggeration here; the creator is simply placing collagen in its proper context, as a specific supplement rather than a base for building muscle. His insistence on the priority of daily protein totals is the most robust current consensus in sports nutrition.

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