Whey protein is today the dietary supplement of choice for most athletes striving to maximize lean muscle growth.
Many scientific studies confirmed the superiority of whey protein in various forms (usually isolate or hydrolizate) over other types of protein, especially soy protein and casein.
There are, however, very few studies comparing a combination of whey and casein protein with whey protein only. Therefore we decided to conduct our own limited mini-trial and see what will work best for our volunteers.
We had 2 groups of 10 young men (average age 22 years, +-1 year). First group was using whey only while the second group was using combination of whey and casein. All 20 volunteers finished the study.
All volunteers had previous experience with resistance training (3.5 years in average).
The test duration was 10 weeks.
Both groups were using protein from a major US producer. The first protein was whey isolate used 4 times a day. The second product was a mixture of whey isolate and micellar casein, also used 4 times a day. Both supplements have been dosed in such a way that they provided for 30 grams of pure protein in each dose.
Training, diet and additional supplementation:
Whole-body resistance training has been applied using between 60% and 90% of 1RM. No additional supplementation was allowed. The volunteers were on normal diet (not on the typical high protein bodybuilding diet with more that 3 daily meals).
Average lean muscle mass growth for the whey group was 1.2 kg in 10 weeks. Average lean muscle mass growth for the whey&casein group was 1.5 kg in 10 weeks.
The total gains for individual volunteers were as follows:
Group 1 (Whey isolate)
Group 2 (Whey isolate & micellar caseine)
Our volunteers didn’t report any side effects during the 10 week mini-trial.
Whey protein combined with micellar casein seem to be more effective for lean muscle mass growth then whey protein only. However, considering the scope and method of this mini-trial we cannot make any unequivocal statements about the efficacy of various forms of proteins.