Soy Vs. Casein for Muscle Mass

If you're sometimes confused about which proteins to use and when, a new study published in the journal Clinical Nutrition tested casein against soy to see which better promoted protein synthesis. Although casein produced a net uptake of more glutamine, serine, histidine and lysine amino acids, both sources worked equally well at promoting protein synthesis and negating the effects of muscle breakdown in a group of 22 healthy subjects, all in the early 20s.

True Strength Moment: Although this research doesn't provide much guidance on protein timing, it's generally recommended that slowly digested casein be used between meals and before bed. Since the majority of muscle rebuilding takes place while you're asleep, an all-micellar casein like Gold Standard 100% Casein can serve as a particularly valuable nutritional tool. Those who've committed to a vegetarian diet will appreciate the fact that soy supports muscle building as effectively as dairy proteins.
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Brian Putchio
Aug 18, 2010
Actually, there's a large missing piece of the puzzle here, which has to do with soy and low-testosterone. According to a study published in the Cancer Epidemiology, Biomarkers & Prevention (2007), which evaluated the effects of isoflavones on serum testosterone and luteinizing hormone (LH), there was a significant 19%(±22%) decrease in the percentage of serum testosterone from day 0 to day 28. Also, according to a 2007 study published in the American Journal of Clinical Nutrition, the consumption of fat-free milk (80% Casein, 20% Whey) post-training resulted in greater muscle hypertrophy (growth) when compared to soy protein. Comparing soy to dairy proteins in this News Article is far from "The Bigger Picture".