GABA
Research reviewed: Up until 03/2026
GABA (Gamma-Aminobutyric Acid) is a dietary supplement with 10 published peer-reviewed studies involving 251 participants, researched for Sleep & Relaxation, Anxiety & Stress, Blood Pressure & Growth Hormone and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Sleep & Relaxation
StrongAnxiety & Stress
StrongBlood Pressure & Growth Hormone
ModerateClinical trials
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Sleep & Relaxation
To evaluate GABA supplementation on sleep quality and sleep latency
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate GABA supplementation on sleep quality and sleep latency
Dose
300 mg GABA before bedtime
Participants
40 adults with sleep difficulties
Duration
4 weeks
Results
Significant reduction in sleep latency (-5.4 min, p=0.02) and improvement in sleep quality. Non-REM sleep time increased. Morning cortisol reduced.
How They Measured It
PSG, PSQI, sleep diary, cortisol
To assess GABA combined with L-theanine on sleep quality
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess GABA combined with L-theanine on sleep quality
Dose
100 mg GABA + 200 mg L-theanine
Participants
40 healthy adults with sleep complaints
Duration
4 weeks
Results
Combination significantly improved sleep duration and quality. Sleep efficiency improved. Alpha brain wave activity increased.
How They Measured It
PSQI, actigraphy, sleep efficiency, brain wave activity
To examine acute effects of GABA on EEG brain activity and stress
Study Type
Randomised, crossover, placebo-controlled
Purpose
To examine acute effects of GABA on EEG brain activity and stress
Dose
100 mg GABA single dose
Participants
13 acrophobic subjects
Duration
Single dose crossover
Results
GABA supplementation significantly increased alpha brain waves and decreased theta waves (p<0.05). IgA levels increased. Stress-reducing effects confirmed via relaxed EEG profile.
How They Measured It
EEG, salivary IgA, cortisol, POMS
To evaluate GABA supplementation on sleep and mood in stressed adults
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate GABA supplementation on sleep and mood in stressed adults
Dose
300 mg/day GABA (Pharma GABA)
Participants
50 healthy adults under chronic stress
Duration
4 weeks
Results
Significant improvement in sleep quality scores, time to fall asleep reduced, and stress perception reduced vs placebo. Urinary GABA levels confirmed absorption.
How They Measured It
PSQI, PSS, STAI, urinary GABA levels
Anxiety & Stress
To evaluate GABA on anxiety and stress responses during a cognitive challenge
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate GABA on anxiety and stress responses during a cognitive challenge
Dose
100 mg GABA
Participants
28 healthy subjects
Duration
Acute assessment
Results
GABA significantly reduced anxiety scores and improved HRV vs placebo during mental arithmetic stress test (p<0.05). Alpha/beta wave ratio improved.
How They Measured It
State anxiety (STAI), heart rate variability, alpha/beta brain wave ratio
To assess oral GABA supplementation on reduction of task-induced anxiety
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess oral GABA supplementation on reduction of task-induced anxiety
Dose
100 mg GABA with food
Participants
30 healthy adults
Duration
4 weeks
Results
Significant reduction in task-associated anxiety (p=0.04). Chromogranin-A salivary marker reduced. Immune marker IgA improved. Relaxation response enhanced.
How They Measured It
STAI-state, salivary chromogranin-A, cortisol, IgA
Blood Pressure & Growth Hormone
To evaluate GABA effects on blood pressure in mildly hypertensive adults
Study Type
Randomised, placebo-controlled
Purpose
To evaluate GABA effects on blood pressure in mildly hypertensive adults
Dose
10-20 mg/day GABA from fermented grain
Participants
39 mildly hypertensive adults
Duration
12 weeks
Results
Significant reduction in systolic BP (5.2 mmHg, p=0.03) and diastolic BP (3.2 mmHg). Heart rate unchanged. Blood pressure lowering effects confirmed.
How They Measured It
24-hr ambulatory blood pressure, heart rate
To assess GABA oral supplementation on growth hormone secretion post-exercise
Study Type
Randomised, crossover, placebo-controlled
Purpose
To assess GABA oral supplementation on growth hormone secretion post-exercise
Dose
3 g GABA before and after exercise
Participants
11 resistance-trained men
Duration
3 weeks crossover
Results
GABA significantly increased resting GH concentration by 400% (p<0.001) and post-exercise GH by 200% vs placebo. Lean body mass trended higher.
How They Measured It
Serum GH, IGF-1, lean mass over time
To review evidence for GABA supplementation effects in humans
Study Type
Systematic review
Purpose
To review evidence for GABA supplementation effects in humans
Dose
Various
Participants
Systematic review
Duration
Various
Results
Evidence supports sleep, anxiety, and blood pressure benefits of oral GABA. Growth hormone stimulation also demonstrated. Bioavailability across blood-brain barrier remains debated. Overall safe profile.
How They Measured It
Systematic review of human RCTs
Clinical trials
To explore the impact of GABA supplementation on sleep quality, emotional response, heart-rate variability, and depression in sedentary overweight women undergoing physical exercise.
Study Type
Randomized, double-blind, placebo-controlled clinical trial
Purpose
To explore the impact of GABA supplementation on sleep quality, emotional response, heart-rate variability, and depression in sedentary overweight women undergoing physical exercise.
Dose
200 mg GABA once daily for 90 days
Participants
30 sedentary women with overweight or obesity
Duration
90 days
Results
GABA supplementation significantly improved sleep efficiency, reduced negative affect and depression scores, and augmented HRV via increased parasympathetic predominance.
How They Measured It
Pittsburgh Sleep Quality Index (PSQI), DASS-21, heart-rate variability (HRV), autonomic nervous system parameters
Frequently Asked Questions
Common questions about GABA research
There are currently 10 peer-reviewed studies on GABA (Gamma-Aminobutyric Acid), involving 251 total participants. Research covers Sleep quality, Anxiety reduction, Stress relief and 2 more areas. The overall evidence strength is rated as Very Strong.
The evidence is currently rated as "Very Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (9 human studies), and reported outcomes.
GABA has been researched for: Sleep quality, Anxiety reduction, Stress relief, Blood pressure, Growth hormone. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 9 out of 10 studies are human trials. Human trials carry more weight in our evidence scoring system.
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