Co-ingesting collagen with whey protein after exercise promotes post-workout recovery and could stimulate muscle synthesis by preventing a drop in glycine.

noli's read

Research effectively shows that collagen, which is rich in glycine, complements the amino acid profile of whey, which contains little of it. A recent study confirmed that this combination prevents the post-exercise drop in plasma glycine levels. However, the idea that this directly 'boosts' myofibrillar protein synthesis is exaggerated: current evidence indicates that whey remains the primary driver of this synthesis due to its high leucine content. While the mixture increases connective tissue protein synthesis, the direct benefit for muscle mass gain compared to whey alone is not clearly demonstrated. Collagen appears to act primarily as support for connective tissue health (tendons, ligaments) rather than as a direct muscle growth factor.

the sources

No named source held this one up — that absence is part of the verdict.