The short answer
Avoid self-starting L-5-HTP while taking desipramine. Official L-5-HTP guidance advises against use with antidepressants; ask the prescriber to review the combination.
What this answer covers
Oral L-5-hydroxytryptophan supplements, not L-tryptophan or ordinary protein foods.
- Supplement or preparation
- L-5-HTP
- Medication ingredient
- desipramine
What the supplement guidance says
Health Canada’s L-5-HTP monograph advises not to use it with antidepressants. Desipramine is an antidepressant, so this precaution applies even without a measured pair-specific risk.
Keep the two precursors distinct
L-5-HTP and L-tryptophan are different ingredients. The desipramine label names tryptophan in its serotonin warning; it does not establish a safe L-5-HTP dose or equivalent gram amount.
Plan changes with the prescriber
Bring the actual L-5-HTP dose and every other mood product. A few hours between doses has not been shown to remove the concern.
Recognize concerning symptoms
Seek urgent medical care for a combination of agitation or confusion, fever or heavy sweating, tremor, muscle rigidity or repeated twitching. These can be signs of serotonin syndrome; a single nonspecific symptom does not establish the diagnosis.
Evidence and practical considerations
Side effects & toxicity
Conditional avoidance/review is supported by exact supplement guidance and desipramine’s serotonin warning, without claiming an observed exact-pair syndrome.
- Exact scope
- Oral L-5-hydroxytryptophan supplements, not L-tryptophan or ordinary protein foods. with Exact oral desipramine hydrochloride tablets. RxNorm IN 3247/PIN 203174 hydrochloride. Mainly norepinephrine reuptake activity does not erase the exact label’s serotonin warning. CYP2D6 inhibition can affect concentrations; not assumed identical to CYP3A substrates.
- Medication form and route
- oral
- Timing or duration
- Source-specific single-dose, repeated-dose and observational exposures distinguished.
What remains uncertain
- No exact human combination trial identified. The desipramine label names tryptophan, not L-5-HTP; the bridge is the separate supplement guidance.
Factors that may matter: preparation and plant part; clinical indication; dose; other medicines; baseline alertness.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed oral desipramine.
Exact label warns about serotonin syndrome with tryptophan and St John’s wort, CYP2D6 inhibition, impaired alertness and cardiovascular/anticholinergic effects.
How this applies: RxNorm IN 3247/PIN 203174 hydrochloride. Mainly norepinephrine reuptake activity does not erase the exact label’s serotonin warning. CYP2D6 inhibition can affect concentrations; not assumed identical to CYP3A substrates.
No universal supplement interval, event rate or preparation equivalence established. Original label distinguishes warnings from measured pair-specific results.
Source 2: official product guidance
webprod.hc-sc.gc.ca · Source check Sep 10, 2026
Population: Adults considering oral L-5-HTP.
Advises not to use with antidepressants; gives serotonergic product precautions and drowsiness caution.
How this applies: The requested medicine is an antidepressant; this is a product-label precaution, not exact-pair clinical proof.
Does not quantify risk with each specific antidepressant or establish a safe supplement dose.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Current exact available claims adjudicated using original captures and explicit identity and comparator limits. | |
| Research summary published |
Article revision: ab50e704f1569826
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.