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Soy and Whey Supplementation Post-Exercise

//Soy and Whey Supplementation Post-Exercise

Soy and Whey Supplementation Post-Exercise

The battle of soy and whey protein on post-exercise supplementation

A consistent and effective workout regime is important, but quality and timely nutrition is also a key component contributing to the efficacy and recovery of the workout.

[blockquote cite=”Drew Prinz” image=”” align=”left”]Everyone is using pre-workout supplements. If you usually do four sets, you will-and then four more.[/blockquote]A recent study posted in the Journal of the American College of Nutrition studied the effects of soy and whey protein supplementation on acute hormonal responses to resistance exercise in men. Hormone response to exercise is significant because hormones play an important role in changes in tissue size, density and function that ultimately result in desirable outcomes such as gains in muscle, strength and power. Testosterone promotes muscle protein synthesis. Soy protein, although an excellent choice for vegetarians, have garnered a bad reputation because they can reduce the bioavailability of testosterone by increasing hepatic production of sex hormone binding globulin (SHBG).

This study was a cornerstone to the emerging industry of pre- and post-workout protein supplements to enhance performance and stimulate better recovery of muscle damage. In this study, a group of 10 men in their early 20s were recruited and separated into 3 treatment groups: whey protein isolate, soy protein isolate, or a maltrodextrin placebo control. No other supplements were allowed on the program, and additionally, vegetarians, vegans or subjects who consumed high-protein diets were excluded from the study.

Subjects ingested 20g of their assigned supplement at the same time each morning before performing 6 sets of heavy resistance squats at 10 reps each using 80 percent of their maximum lifting weight.


[highlight highlightColor=”highlight-blazeorange” ][/highlight]The main finding of the study is that there was a difference of the effect each type of protein had on acute hormones. After 14 days of supplementation, soy protein partially blunted serum testosterone while whey protein blunted the rise of cortisol after exercise during recovery.

The authors did not conclude with any recommendations in regards to the type of protein to consume to confer the best workout results, but the finding that soy protein may decrease the amount of serum testosterone, which is the hormone that helps to signal the growth of muscles, may be an indicator that whey protein is the better pre-workout drink for body builders.


  • William J. Kraemer, Glenn Solomon-Hill, Brittanie M. Volk, Brian R. Kupchak, David P. Looney, Courtenay Dunn-Lewis, Brett A. Comstock, Tunde K. Szivak, David R. Hooper, Shawn D. Flanagan, Carl M. Maresh, Jeff S. Volek. The Effects of Soy and Whey Protein Supplementation on Acute Hormonal Reponses to Resistance Exercise in Men. Journal of the American College of Nutrition, 2013; 32 (1): 66 DOI: 10.1080/07315724.2013.770648