NutriStack
Melatonin and Passionflower, a caution.
Passionflower adds GABAergic sedation on top of melatonin's sleep-promoting effect, increasing overall drowsiness and next-morning grogginess in some users.
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
- Substances
- Melatonin and Passionflower
- 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. Passionflower adds GABAergic sedation on top of melatonin's sleep-promoting effect, increasing overall drowsiness and next-morning grogginess in some users.
Mechanism. Melatonin acts on MT1 and MT2 receptors to promote sleep onset while passionflower enhances GABA-A signaling, producing additive CNS sedation through distinct pathways.
Recommendation. Take near bedtime only, start with low doses, and avoid driving after dosing. Avoid stacking with other sedatives or alcohol.
Sources (2)
- Appel K et al. Modulation of the γ-aminobutyric acid (GABA) system by Passiflora incarnata L. Phytother Res. 2011;25(6):838-43. PMID 21089181
- 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
Stack Score
How this pair moves the number.
Effect on the composite score
If both Melatonin and Passionflower 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.
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