Research & Education

The Synergistic Activity of GABA and L-Theanine for Sleep

Poor sleep is associated with an increased risk of chronic health conditions including cardiovascular disease, metabolic syndrome, diabetes, Alzheimer’s disease, and mental health conditions. Acquiring 7 to 8 hours of sleep per night is associated with better health outcomes. Many factors may contribute to insufficient sleep duration and/or low-quality sleep, including diet, lifestyle, biology, genetics, health, environment, and psychosocial and socioeconomic factors. One component that may support relaxation and thereby promote quality sleep is to support neurotransmitter balance.

Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter blocking nerve impulses and slowing down the activity of nerve cells to prevent overfiring. GABA works in balance with glutamate, the main excitatory neurotransmitter. Imbalances between the two may contribute to dysfunction and affect sleep. Increasing GABA levels may promote calm and relaxation.* GABA also regulates other neurotransmitters including dopamine and serotonin (a precursor to melatonin) that may also support restful sleep.*

In one study on the supplementation of GABA, researchers demonstrated that GABA increased production of alpha waves, which are produced during relaxation. They also demonstrated that GABA decreased beta waves, which are associated with situations of high stress. Additionally, a systematic review found promising evidence that oral GABA consumption induces and improves the early stages of sleep.

L-theanine is a nonprotein amino acid found in green tea that also promotes calm and relaxation.* L-theanine has an analogous structure to glutamate, so it may bind to glutamate receptors and inhibit glutamatergic activation and the associated neuroexcitatory effects. Studies have also found that it may promote the release of GABA. It may also support the increase of alpha wave transmission. Thus, L-theanine supports the balance of the excitatory and inhibitory neurotransmitters and may promote relaxation.*

GABA and L-theanine support similar functions, and this may cause them to act synergistically to support restful sleep.* In an animal study, mice were given a mixture of 100 mg of GABA and 20 mg/kg of L-theanine. The mice underwent electroencephalogram (EEG) analysis. Consuming the GABA/L-theanine mixture led to a decrease in sleep latency and an increase in sleep duration compared to either GABA or L-theanine alone. The mixture also contributed to a significant increase in rapid eye movement (REM) and non-REM sleep compared to the controls. In an arousal model of mice, the mixture normalized sleep time and quality. This study demonstrates the potential for GABA and L-theanine to act synergistically to improve sleep quality and duration.

Many factors contribute to sleep disturbances, which may require various actions to support restful sleep. One method may be to promote relaxation by supporting inhibitory neurotransmitter production. Although there are multiple ways to accomplish this, some individuals may find a supplement that combines GABA and L-theanine to be beneficial for the synergistic promotion of sleep quality.*

By Kendra Whitmire, MS, CNS