Even though these protein shakes had less amino acids than previously thought necessary, they still effectively boosted muscle protein building in young men.

Both types of protein shakes boosted muscle protein building similarly in young men, whether they were resting or exercising after drinking them.

Young men who drank a β-lactoglobulin protein shake had higher blood leucine levels over time than those who drank regular whey protein, but their muscles built protein at the same rate.

Young men who drank β-lactoglobulin had higher levels of branched-chain and essential amino acids in their blood over time compared to those who drank regular whey protein.

When young men consumed β-lactoglobulin, their blood leucine levels peaked higher than when they consumed regular whey protein.

When older women drink whey protein shakes, their muscles start repairing and growing faster—especially if they also do leg exercises—while collagen protein shakes don’t do much unless they exercise, and even then, it’s much weaker.