Collagen and whey are both proteins.
They shouldn’t be treated as interchangeable.
Whey is a complete, leucine-rich protein and has strong evidence for supporting muscle adaptation when combined with resistance training.
hydrolysed collagen have a different amino acid profile.
The more interesting research around collagen concerns connective tissues such as tendons, ligaments, cartilage and skin.
So within natural sports nutrition, the question isn’t:
Whey or collagen?
It’s:
What are you trying to support?
Muscle protein requirements? Prioritise high-quality complete protein.
Connective-tissue nutrition? That’s where collagen becomes more interesting.
Different proteins.
Different jobs.