5-HTP and medications.
5-HTP is not in the Distil recommendation database. We surface it here deliberately, because why a compound is left out is as useful as what we recommend.
5-HTP is a direct precursor to serotonin. On its own that is not the problem. The problem is that it stacks with anything else that raises serotonin: SSRIs, SNRIs, the older tricyclics, and MAOIs. That combination carries a real risk of serotonin syndrome, which ranges from unpleasant to dangerous.
Many people who reach for 5-HTP for mood or sleep are also on a serotonergic medicine, often without thinking of it as one. So we treat 5-HTP alongside an SSRI or SNRI as a hard exclusion rather than a "use with caution", and it stays out of the database. If sleep is the goal, the options below carry none of that risk.
What to consider instead. Every option below is in the Distil database, so you can check each against your own medications:
- Magnesium Glycinate: the glycine half does most of the calming; no serotonergic action
- Glycine: 3g at bedtime, lowers core temperature and tends to ease sleep onset
- Melatonin: for sleep timing rather than mood
We still hold the documented interactions for 5-HTP, which is why it stays in the interactions checker even though we do not recommend it. Below are the 28 documented pairs we have explicitly assessed: 15 red and 13 amber. Every call is cited to a clinical reference (PMID) or the British National Formulary.
Documented interactions
Last reviewed 30 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
Additive serotonergic activity
Red Does interact with Citalopram?
5-HTP is the precursor your body uses to make serotonin. Combined with an SSRI like citalopram, it can cause serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Duloxetine hydrochloride?
5-HTP raises serotonin levels. Combined with an SNRI like duloxetine, it can cause serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Escitalopram?
5-HTP raises serotonin levels. Combined with an SSRI like escitalopram, it can cause serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Fluoxetine hydrochloride?
5-HTP is the precursor your body uses to make serotonin. Combined with an SSRI like fluoxetine, it can cause serotonin syndrome (agitation, sweating, tremor, confusion). Do not combine.
Evidence: Supported by human study data.
Red Does interact with Fluvoxamine?
5-HTP is the precursor your body uses to make serotonin. Combined with an SSRI like fluvoxamine, it can cause serotonin syndrome (agitation, sweating, tremor, confusion). Do not combine.
Evidence: Supported by human study data.
Red Does interact with Isocarboxazid?
5-HTP raises serotonin levels. Combined with an MAOI like isocarboxazid, this can produce severe serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Linezolid?
5-HTP is the precursor your body uses to make serotonin, and linezolid is an antibiotic that also acts as an MAOI, blocking serotonin breakdown. Combining them can drive serotonin to dangerous levels, a reaction called serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Moclobemide?
5-HTP is the precursor your body uses to make serotonin, and moclobemide is an MAOI (the reversible kind) that blocks serotonin breakdown. Combining them can drive serotonin to dangerous levels, a reaction called serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Paroxetine hydrochloride?
5-HTP raises serotonin levels. Combined with an SSRI like paroxetine, it can cause serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Phenelzine?
5-HTP raises serotonin levels. Combined with an MAOI like phenelzine, which blocks serotonin breakdown, this can produce severe serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Rasagiline?
Taking 5-HTP with rasagiline (an MAO-B inhibitor used for Parkinson's) can push serotonin to dangerous levels, because there is less MAO available to break it down, so we treat this as a do-not-combine pair. The combination has caused serotonin syndrome in case reports with other MAO inhibitors.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does interact with Selegiline?
Taking 5-HTP with selegiline (an MAO-B inhibitor used for Parkinson's) can push serotonin to dangerous levels, because there is less MAO available to break it down, so we treat this as a do-not-combine pair. The combination has caused serotonin syndrome in case reports with other MAO inhibitors.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does interact with Sertraline?
5-HTP is the precursor your body uses to make serotonin. Combined with an SSRI like sertraline, it can cause serotonin syndrome (agitation, sweating, tremor, confusion). Do not combine.
Evidence: Supported by human study data.
Red Does interact with Tranylcypromine?
5-HTP raises serotonin levels. Combined with an MAOI like tranylcypromine, this can produce severe serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Red Does interact with Venlafaxine?
5-HTP raises serotonin levels. Combined with an SNRI like venlafaxine, it can cause serotonin syndrome. Do not combine.
Evidence: Supported by human study data.
Amber Does interact with Amitriptyline?
Amitriptyline has weak serotonin-reuptake-inhibiting activity. Combined with 5-HTP, the serotonergic effect is additive. Watch for restlessness, sweating, or muscle twitching, and discuss with your GP before stacking.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Clomipramine?
Clomipramine is the most strongly serotonin-acting of the tricyclics. Combined with 5-HTP, the serotonergic effect is additive and more likely to add up than with other TCAs. Watch for restlessness, sweating, or muscle twitching, and discuss with your GP before stacking.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Dosulepin?
Dosulepin has serotonin-reuptake-inhibiting activity. Combined with 5-HTP, the serotonergic effect is additive. Watch for restlessness, sweating, or muscle twitching, and discuss with your GP before stacking.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Doxepin?
Doxepin has serotonin-reuptake-inhibiting activity, and 5-HTP raises serotonin, so combining them adds to the serotonin effect. Watch for restlessness, sweating, or muscle twitching, and discuss with your GP before stacking.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Imipramine?
Imipramine has serotonin-reuptake-inhibiting activity. Combined with 5-HTP, the serotonergic effect is additive. Watch for restlessness, sweating, or muscle twitching, and discuss with your GP before stacking.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Lithium carbonate?
5-HTP is the direct building block your body turns into serotonin, and lithium can increase serotonin activity in the brain. Combined, they may add up, which in theory can raise the risk of serotonin syndrome (agitation, sweating, tremor, fast heartbeat, confusion). Lithium also has a narrow safe range of its own, so tell your GP or specialist you take 5-HTP and watch for those symptoms, especially after any dose change.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Lofepramine?
Lofepramine has serotonin-reuptake-inhibiting activity. Combined with 5-HTP, the serotonergic effect is additive. Watch for restlessness, sweating, or muscle twitching, and discuss with your GP before stacking.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Nortriptyline?
5-HTP raises serotonin, while nortriptyline works mainly on noradrenaline and has only weak serotonin activity. Any added serotonin effect is likely to be small, but it is worth mentioning the 5-HTP to your GP and watching for restlessness, sweating, or muscle twitching, especially if your dose has recently changed.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Sumatriptan succinate?
5-HTP is the direct building block your body turns into serotonin, and sumatriptan is a serotonin-receptor drug used for migraine. In theory, taking them together could add to your serotonin activity. The evidence that triptans actually cause this problem is weak and most people tolerate the combination, but it is worth telling your GP you take 5-HTP, especially if you are also on an antidepressant, and being alert to symptoms like agitation, sweating, tremor, fast heartbeat or confusion.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Tramadol hydrochloride?
5-HTP is the building block your body uses to make serotonin, and tramadol raises serotonin as part of how it works. Combining them may increase the risk of serotonin syndrome (agitation, sweating, tremor, shivering, a racing heart). Do not stack them without your prescriber's involvement, and be especially careful if your tramadol dose has recently increased.
Evidence: Supported by human study data.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Trazodone hydrochloride?
5-HTP is the direct building block your body turns into serotonin, and trazodone is an antidepressant that also acts on serotonin. Combining them may add to your serotonin activity, which can in theory raise the risk of serotonin syndrome (agitation, sweating, tremor, fast heartbeat, confusion). It is worth telling your GP you take 5-HTP and watching for those symptoms, particularly after a dose change.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Vortioxetine?
5-HTP is the direct building block your body turns into serotonin, and vortioxetine is an antidepressant that works mainly through serotonin. Taking them together may add to your serotonin activity, which can in theory raise the risk of serotonin syndrome (agitation, sweating, tremor, fast heartbeat, confusion). It is worth telling your GP you take 5-HTP and being alert to those symptoms, especially around a dose change.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Zolmitriptan?
5-HTP is the direct building block your body turns into serotonin, and zolmitriptan is a serotonin-receptor drug used for migraine. In theory, taking them together could add to your serotonin activity. The evidence that triptans actually cause this problem is weak and most people tolerate the combination, but it is worth telling your GP you take 5-HTP, especially if you are also on an antidepressant, and being alert to symptoms like agitation, sweating, tremor, fast heartbeat or confusion.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this page does not say. Leaving a compound out of our recommendations is not a verdict that it is useless for everyone. It is a statement about safety, evidence, or interaction load in the context Distil screens for. Discuss any supplement decision with whoever manages your prescriptions.
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How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyA full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
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