Effect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-Controlled Crossover Trial

source extracted confidence: high 2026-04-09
#adult #caseins #cross-over-studies #double-blind-method #glutamates

Effect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-Controlled Crossover Trial

Thiagarajah et al., 2022 | Nutrients | Rct

Citation

Thiagarajah Kokila, Chee Huei Phing, Sit Nam Weng. 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-03;14(3). doi:10.3390/nu14030652

Abstract

This randomized, placebo-controlled, crossover and double-blind study investigates the effects of RLX2™ containing alpha-s1-casein tryptic hydrolysate and L-theanine in working adults affected by poor sleep quality. The supplement or placebo was randomly and blindly assigned to 39 subjects for four weeks and the changes in the subjective sleep assessment via the Pittsburgh Sleep Quality Index (PSQI), heart rate, blood pressure, salivary cortisol by high-performance liquid chromatography method and alpha power of awake electroencephalogram (EEG) were studied. The data were analyzed in two ways, by crossover and crossover summed up. The latter depicted that RLX2™ improved PSQI total score, sleep latency, sleep duration, sleep habitual efficiency, daytime dysfunction, and increased total and frontal alpha power significantly (p < 0.05). The supplement prolonged the total sleeping time by 45 min in the supplement receiving group compared to the placebo group (p < 0.001). However, only sleep duration and sleep habitual efficiency showed a profound effect in both analyses (p < 0.05). In conclusion, being given its beneficial effects without notable adverse events, it would be advantageous to use these nutraceutical ingredients to promote better sleep quality. Further studies with a larger number participants are warranted to support these findings.

Key Findings

Further studies with a larger number participants are warranted to support these findings.

Outcomes Measured

  • sleep quality
  • sleep duration
  • PSQI (Pittsburgh Sleep Quality Index)
  • blood pressure
  • cortisol levels

Population

Field Value
Population See abstract
Sample Size 39
Age Range See abstract
Condition sleep

MeSH Terms

  • Adult
  • Caseins
  • Cross-Over Studies
  • Double-Blind Method
  • Glutamates
  • Humans
  • Sleep Quality

Evidence Classification

  • Level: Rct
  • Publication Types: Journal Article, Randomized Controlled Trial
  • Vertical: l-theanine-sleep

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09