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Head-to-head evidence comparison — which supplement is right for you?
GABA wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
2 of 2 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
4 of 4 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (3)
Outcomes where both GABA and Passionflower have evidence — compare verdict strength side-by-side.
250-750mg
30-60 minutes before desired effect, Before bed for sleep, Before stressful events for anxiety
Capsules or powder
250-500mg extract (or 2g dried herb)
For anxiety: as needed, For sleep: 30-60 minutes before bed
Standardized extract capsules
30-60 minutes
30-60 minutes
30-60 minutes
30 min - 2 hours
30-60 minutes
30-60 minutes
Herbal Remedies and Their Possible Effect on the GABAergic System and Sleep
Nutrients (2021) · Systematic review
Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that plays a major role in controlling different vigilance states.
Effect of Probiotics on the Symptomatology of Autism Spectrum Disorder and/or Attention Deficit/Hyperactivity Disorder in Children and Adolescents: Pilot Study
Research on child and adolescent psychopathology (2025) · Rct · n=80
A better comfort score (quality of life) was shown in children with ASD (probiotic: p = 0.010, Cohen's d = 0.722; placebo: p = 0.099, Cohen's d = 0.456).
GABA Supplementation, Increased Heart-Rate Variability, Emotional Response, Sleep Efficiency and Reduced Depression in Sedentary Overweight Women Undergoing Physical Exercise: Placebo-Controlled, Randomized Clinical Trial
Journal of dietary supplements (2024) · Rct · n=90
Moreover, an improved emotional response was observed, characterized by diminished negative affect.
Herbal Remedies and Their Possible Effect on the GABAergic System and Sleep
Nutrients (2021) · Systematic review
Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that plays a major role in controlling different vigilance states.
Passiflora incarnata in Neuropsychiatric Disorders-A Systematic Review
Nutrients (2020) · Systematic review
Passiflora incarnata may be helpful in treating some symptoms in neuropsychiatric patients.
Herbal medicine for depression and anxiety: A systematic review with assessment of potential psycho-oncologic relevance
Phytotherapy research : PTR (2018) · Systematic review
Overall, 45% of studies reported positive findings with fewer adverse effects compared with conventional medications.
Limited direct GABA supplementation studies. Most evidence comes from GABA receptor agonist research showing somnolence as primary effect (RR 4.56). Effectiveness estimates are conservative given sparse direct supplementation data and questionable oral bioavailability of GABA across blood-brain barrier.
Based on meta-analysis of 198 subjects noting insufficient RCT data for definitive conclusions. Effectiveness limited by small sample sizes and study quality limitations. Drowsiness is primary dose-limiting side effect.
AI-estimated from published studies. Interpret as directional guidance.
GABA has a higher evidence score (8.5/10 vs 8/10) and wins in 2 of 3 categories.
For reduce anxiety & stress, Passionflower has a higher relevance score (85 vs 75).
No known interactions between GABA and Passionflower have been documented in our database. However, always consult a healthcare provider before combining supplements.