NutriStack
GABA and Melatonin, a caution.
Combined use for sleep can produce additive drowsiness and next-morning grogginess, and both lower nighttime arousal.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Caution · Emerging evidence
Caution
What is happening. Combined use for sleep can produce additive drowsiness and next-morning grogginess, and both lower nighttime arousal.
Mechanism. Melatonin shifts circadian timing and promotes sleep onset via MT1/MT2 receptors while GABA increases inhibitory tone; together they can deepen sedation and lower arousal more than either alone.
Recommendation. If combining for sleep, take both shortly before bed, keep doses modest, and avoid activities requiring alertness afterward.
Sources (2)
- Costello RB et al. The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature. Nutr J. 2014;13:106. PMID 25380732
- Boonstra E et al. Neurotransmitters as food supplements: the effects of GABA on brain and behavior. Front Psychol. 2015;6:1520. PMID 26500584
Stack Score
How this pair moves the number.
Effect on the composite score
If both GABA and Melatonin are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.