For rats, the best time for muscle protein building after eating regular whey protein is about an hour later.

When rats exercised and then ate a small amount of whey protein hydrolysate, their muscles built protein faster than when they ate regular whey protein at the same dose.

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.

When rats swam for two hours and then consumed whey protein, their muscle building rate peaked at 60 minutes with a value of 7.76% per day.

Eating a big protein meal (100g) after working out makes your muscles keep building for longer than a smaller meal (25g), at least for 12 hours.

If you feed adult rats protein from sources like whey or eggs instead of wheat or soy, their muscles grow bigger and repair faster after eating, especially after the first meal of the day.