The participants spent 4 consecutive nights in a sleep lab. At 9:00 p.m. on nights 2 through 4, the participants consumed a low-dose supplement drink, a high-dose supplement drink, or a placebo drink.

The supplement drinks contained whey protein (30 grams in the lower dose, 40 grams in the higher dose), tryptophan (641 mg in the lower dose, 855 mg in the higher dose), theanine (660 mg), and adenosine monophosphate (53 μg), and a small amount of high-glycemic-index carbohydrates (2.7 grams).

The supplements had no clear effect on total sleep time, sleep efficiency, sleep latency, or sleep quality.

No effect of whey protein, tryptophan, and theanine-containing supplements on sleep Original paper