Compound or practice · Supplement
GABA (Supplement)
The brain's calming neurotransmitter in a pill — which mostly can't cross into the brain.
- Overall grade
- Grade D
- Last revised
- 1
- graded outcome
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
1 at grade D — 1 graded row
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Relaxation / stressEvidence grade D
Poor brain entry
Triviallow
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Relaxation / stress (grade D).
Interactions
Documented pairings with supplements and medicines. A medicine on this list is a conversation for whoever prescribes it.
L-TheanineWorks together
Sometimes combined for calm; theanine is better supported.
The evidence in words
What it is
Oral GABA is sold for relaxation and sleep, though the neurotransmitter itself poorly crosses the blood–brain barrier.
How it works
GABA is the main inhibitory neurotransmitter, but supplemental GABA's central effects are limited by poor brain entry; any effect may be via the enteric nervous system.
What the evidence shows
A few small studies report relaxation or stress-marker changes, plausibly via gut–brain signaling rather than direct central action; evidence is weak. Effects, if real, are mild.
How to use it
100–300 mg if trialing, evening.
Safety & interactions
Generally safe; additive with other sedatives. L-Theanine — Sometimes combined for calm; theanine is better supported.
Bottom line
The mechanism argues against it and the evidence is thin. Theanine or glycine are better-supported calm/sleep options.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- If trialing
- 100–300 mg, evening.
Goes with
- L-TheanineSometimes combined for calm; theanine is better supported.Evidence grade B
Related reading
Entries that share this one's tags or conditions.
- ApigeninThe chamomile flavone behind the bedtime-tea calm — mild, benign, thinly studied as an isolated supplement.Evidence grade C
- GABA (Supplement) for Relaxation / stressEvidence grade D — Poor brain entryEvidence grade D
- GABA (Supplement): dosage and how to take it100–300 mg, evening.Evidence grade D
- GABA (Supplement): side effects, safety & interactionsGenerally safe; additive with other sedatives.Evidence grade D
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.