Athletes, take note: When it comes to building lean muscle, whey reigns as the king of protein.

A new study published in the Journal of the American College of Nutrition found that taking whey protein after working out helped participants build more lean muscle than those who consumed soy protein. Click here to read the study.

“The results of the study highlight the importance of protein quality in effective muscle repair after exercise,” Greg Miller, executive vice president of the National Dairy Council, wrote in a blog post. “Whey protein is a high quality protein source: not only is it full of branched-chain amino acids, which have been shown to stimulate muscle repair, but it is also easily digested. In comparison, despite being easy to digest, soy protein doesn’t boast the same benefits.”  

Whey doesn’t just help build lean muscle. Another study released in 2012 showed that whey protein also battle age-related muscle loss, making it more than just a dairy by-product.