Moderate interactionModerate
5-HTP and L-tryptophan: interaction, severity and spacing
5-HTP and L-tryptophan interact because both raise serotonin synthesis through the same pathway, so the effects add. Take them with care. Moderate risk.
Last reviewed: 2026-09-20Reviewed by: StackingRight clinical review
The interaction in detail
| Pair | 5-HTP and L-tryptophan |
|---|---|
| Type | Nutrient interaction |
| Severity | Moderate |
| Required spacing | None specified |
| Onset | At the time of dosing |
Mechanism
Both raise serotonin synthesis through the same pathway, so the effects add.
What to do
Choose one, not both. If using both, keep doses low and stop if you notice agitation or tremor.
How to fit both into one day
5-HTP
pre-bedflexible
Take 5-HTP before bed. Never combine with an SSRI or with tryptophan because the serotonin effect is additive.
L-tryptophan
pre-bedempty stomach
Tryptophan is the serotonin and melatonin precursor. Take it away from protein, which competes for the same transporter, and before bed.
Putting 5-HTP in the pre-bed and L-tryptophan in the pre-bed satisfies the 0-hour separation without disrupting either one's absorption window.