A recent study published in August 2019 in the Journal of Human Kinetics found that consumption of Whey Protein or Milk-based recovery drinks didn't improve muscle recovery, soreness or produce muscle gains any more than a carbohydrate-only drink.
The double-blind study recruited 30 university students 20-30-year-old males, who have been resistance training for at least one year before and during the study. Participants were randomly split into three different groups:
1. Whey hydrolysate-based protein drink
2. Milk-based protein drink
3. Flavored dextrose/carbohydrate drink
In summary, consumption of WH or MB did not enhance recovery of dynamic power producing ability or perceived muscle soreness compared to an isocalorific carbohydrate-only condition. Ingestion of WH and MB had seemingly marginal to small effects on recovery of isokinetic flexion torque. However, these effects were not as pronounced as described within previous related literature, which has demonstrated between-group differences for recovery of muscle function following ingestion of protein-carbohydrate drinks compared to carbohydrate-only conditions.
Bicycle Magazine also reported on this study: