This randomized, double-blinded, placebo-controlled and crossover study examined the effects of alpha-S1-Casine tryptic hydrolysate and L-theanine on sleep quality. 39 subjects with poor sleep quality received their supplements for 4 weeks.

Compared to placebo, the product improved PSQI total score, sleep lantency, sleep duration, sleep habitual efficiency, daytime dysfunction, and increased total and frontal alpha power significantly (p < 0.005). The supplement prolonged the total sleeping time by 45 min in the supplement receiving group compared to the placebo group (p < 0.001).

Therefore, the tested combination is effective for improving sleep quality.

Thiagarajah K, Chee HP, Sit NW. Effect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-Controlled Crossover Trial. Nutrients. 2022 Feb 3;14(3):652.