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5-Hydroxytryptophan

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Subjective Effects

Interactions

Tolerance

5-Hydroxytryptophan (5-HTP) is a naturally occurring amino acid and metabolic intermediate in the biosynthesis of serotonin and melatonin. It is sold as a dietary supplement for mood, sleep, and appetite-related purposes and is used medically in some countries for depression. Although several controlled trials report antidepressant effects, the available evidence lacks sufficient high-quality research. Combining 5-HTP with serotonin-releasing substances is not recommended.

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Threshold25 mg

Light50-100 mg

Moderate100-200 mg

Strong200-300 mg

Heavy500+ mg

5-Hydroxytryptophan should not be taken concurrently with serotonergic substances. Following use of MDMA or similar serotonin-releasing agents, a minimum interval of 24 hours is advised before supplementation to reduce the risk of serotonin syndrome.

Duration

Onset30-60 minutes

Total4-6 hours

Subjective Effects

Subjective Effects not written up yet

Pharmacology

Pharmacodynamics

5-HTP acts as a serotonin precursor, increasing serotonin production within central nervous system tissue. In rodents, high doses induce a head-twitch response that depends on conversion of 5-HTP to serotonin and is blocked by 5-HT2A receptor antagonists. This response is also abolished by inhibitors of indolethylamine N-methyltransferase, suggesting involvement of downstream N-methylated tryptamines.

Pharmacokinetics

5-HTP crosses the blood-brain barrier and is rapidly decarboxylated to serotonin by aromatic L-amino acid decarboxylase in nervous tissue and the liver. This conversion is vitamin B6 dependent. Excess 5-HTP, particularly when administered with vitamin B6, is thought to be metabolized and excreted.

Interactions

Interactions not written up yet

An unlisted combination is an unknown one, not a safe one. Check a dedicated combination chart before mixing.

Check

TripSit

Tolerance

Tolerance not written up yet

Harm Potential

Toxicity

Cardiovascular system

Prolonged use may carry a significant risk of heart valve disease. Rare adverse cardiovascular effects, typically reported at higher doses, include abnormal heartbeat, increased heart rate, and increased blood pressure.

Musculoskeletal and hematologic systems

Eosinophilia-myalgia syndrome, involving extreme muscle tenderness, myalgia, and blood abnormalities, has been associated with some 5-HTP supplements.

History & Culture

5-HTP has been used medically and as a dietary supplement under the international nonproprietary name oxitriptan, particularly for depression and other indications. It has been marketed under brand names including Cincofarm, Levothym, Levotonine, Oxyfan, Telesol, Tript-OH, and Triptum, and has also…

Legality

International

5-Hydroxytryptophan is not listed in the current INCB Yellow List under the 1961 Convention or Green List under the 1971 Convention, and it is not listed in either precursor table of the 1988 Convention.

By Country

Controlled / restricted3

Czech RepublicRestricted

NetherlandsRestricted

SwitzerlandRestricted

Prescription1

FrancePrescription only

Legal / decriminalized2

CanadaLegal (regulated)

ColombiaLegal (regulated)

Not scheduled7

United StatesNot scheduled

AustraliaNot scheduled

BrazilNot scheduled

DenmarkNot scheduled

IndonesiaNot scheduled

IrelandNot scheduled

United KingdomNot scheduled

References

Citations

Article Status

Step 1 · Automated synthesis
An autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.
Step 2 · First-pass reviewPending
Not yet reviewed — this article is pending editorial review by Lyrea.
Step 3 · Citation reviewPending
No one has reviewed this article's citations yet. That second pass checks each claim against the source it cites.

Recent changes7 human edits · latest 24 Jan

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24 January 2026

23:32
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
23:25
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
23:20
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
23:15
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
22:57
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
22:42
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more
22:21
Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

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