Aim of the study:
It is a widespread belief among bodybuilders that use of casein before the sleep helps protein synthesis in the night or at least stops catabolic processes. The rationale behind this belief is as follows: since the metabolism slows down but doesn’t completely stop during the night, bodybuilder needs to have a sufficient source of calories for this lengthy period of time.
Casein is thought to be ideal for such aim as it creates a clog in the stomach and the protein is released gradually. So at least the theory goes.
The fact is that this theory has never been tested in a controlled clinical study (as far as we are aware). Therefore we decided to conduct this limited non-scientific test.
26 male volunteers between the age of 18 and 26 years were divided into 2 groups: casein group (C group) and control group (CT group). One volunteer from the CT group didn’t complete the study because of an illness unrelated to the study.
The average weight of the volunteers was 81.4 kg.
Methods and products used:
Volunteers in the casein group were given 50 grams of pure, commercially available water-soluble powder (100% Casein, Gold Standard by Optimum Nutrition) every evening before sleep.
Volunteers in the control group were subject to the same resistance training and diet, but instead of the 50g of casein in the evening they were given increased protein dosage during the day so that the 2 groups would have the same daily protein intake.
No placebo has been used in the control group.
Duration of the study:
The duration of this limited study was 7 weeks.
Training, diet and additional supplementation:
Both groups of volunteers were on high-protein diet (about 1.5 g of protein per 1 kg of own body weight per day) and subject to heavy-resistance training 3 times a week during whole duration of the test.
The training consisted mostly of 3 exercises: barbell squats, dumbbell pres and v-bar pulldowns.
No other supplements were allowed two weeks before the study and during the study.
The total muscle mass increase for the casein group was 2.2 kg per one person.
The total muscle mass increase for the control group was 2.15 kg per one person.
This limited test didn’t prove the correlation between casein use before sleep and improved muscle mass growth. The differences between the two groups were not statistically significant. Further trials are needed to prove or rule out such correlation.