Effects of combined GABA and L-theanine supplementation on sleep quality: an exploratory study.

Combined GABA and L-theanine supplementation for 4 weeks significantly improved total PSQI scores in adults with sleep problems.

• Total PSQI score improved from 9.42 ± 1.80 before to 6.26 ± 1.66 after supplement intake
• Mean difference was -3.15 (95% CI: -4.01 to -2.31)
• Improvement was statistically significant (p < 0.001)
• Study used a single-arm design with 19 participants
• Supplementation consisted of GABA 700 mg/day and L-theanine 200 mg/day over 4 weeks

Sleep recovery scores measured by Fitbit Charge 5 improved significantly after 4 weeks of GABA and L-theanine supplementation.

• Sleep recovery scores are 25-point scores calculated from heart rate during sleep, heart rate at rest, and time of turning over in bed
• Improvement in sleep recovery scores was statistically significant (p = 0.042)
• Sleep-related data were measured using the Fitbit Charge 5 wearable device
• Data were evaluated before and after the supplement intake period

Heart rate during sleep decreased significantly in the first week of GABA and L-theanine supplementation.

• Heart rate during sleep decreased by 1.3 bpm in the first week of intake
• This decrease was statistically significant (p = 0.045)
• Heart rate data were collected via Fitbit Charge 5

The study was designed as a single-arm exploratory study of adults with sleep problems receiving combined GABA and L-theanine supplementation.

• 19 participants completed the study and provided results
• Participants had pre-existing sleep problems
• Supplements were taken for 4 weeks
• Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and Fitbit Charge 5 device data
• Authors noted the need for further randomized controlled trials to confirm findings