Nootropics Index - Save on smarter supplements
Nootropics>Amino acids & derivatives>5-HTP
Amino acids & derivatives

5-HTP

5-hydroxy-L-tryptophan

5-HTP is a serotonin and melatonin precursor available as capsules and powders, often sourced from Griffonia seed extract. It has limited and mixed human evidence for mood and sleep contexts, not strong healthy nootropic evidence. The main buyer issue is interaction and quality context: compare products by actual 5-HTP content and regard serotonergic combinations as a specific safety check.

CalmRelaxationSleep SupportMood SupportSerotonergicNeurotransmitter PrecursorMonoamine Related
Updated August 2026/6 min read/10 citations
Reviewed by the NootropicsIndex editorial team.Method: prioritize cited human research and official safety or regulatory sources; compare retailer-listed prices without endorsing products.Affiliate disclosure
01

What is it?

What 5-HTP is

3

5-HTP is 5-hydroxy-L-tryptophan, an intermediate compound the body makes from tryptophan on the way to serotonin and melatonin. Supplement products may be isolated 5-HTP or Griffonia simplicifolia seed extract standardized for 5-HTP content, so labels need more scrutiny than the short name suggests.

02

Names, aliases and forms

Common Name5-HTP
Chemical Names5-hydroxytryptophan; 5-hydroxy-L-tryptophan
AbbreviationL-5-HTP
03

Mechanisms of action

Serotonin precursor does not mean safer stacking

1

5-HTP bypasses the tryptophan-to-5-HTP step and can increase serotonin-pathway substrate availability. That mechanism is why it is marketed for mood and sleep, but it is also why combining it with antidepressants, serotonergic drugs or other serotonin-support supplements can become unsafe.

04

Potential effects and evidence map

5-HTP sits between tryptophan and serotonin/melatonin pathways, but supplement evidence is not strong enough for broad cognitive-performance claims. Cochrane found tryptophan/5-HTP mood evidence limited by small, older studies, and the recent sleep trial was small and population-specific. For a comparison page, the evidence and safety story is mostly dose/form/interaction discipline rather than positioning 5-HTP as a general nootropic.

Effect domainMagnitudeGrade
Mood / wellbeing2
CumulativeConfidence: Medium

5-HTP has limited human mood-related research, but the evidence is not strong enough for broad self-directed mood claims.

Note Cochrane found the evidence limited by small, older studies and incomplete safety data; avoid disease-treatment language.

2/5
C
Sleep quality5
CumulativeConfidence: Low

Small human studies suggest possible sleep-quality effects in specific populations, but this should not be framed as a reliable sleep aid for everyone.

Note The 2024 older-adult RCT used 100 mg/day for 12 weeks and is population-specific, not universal proof.

2/5
C
Calm / relaxation3
UnknownConfidence: Low

Relaxation claims are mechanistically plausible through serotonin pathways but too indirect for strong public claims.

Note Use mechanism context only; do not imply predictable anxiolytic effects.

1/5
D
Focus / attention3
UnknownConfidence: Medium

5-HTP should not be positioned as a focus, productivity or stimulant nootropic.

Note Current evidence is mood/sleep/serotonin pathway oriented, not attention enhancement.

0/5
E
05

Typical dosages and timing

Typical
100-300 mg/day
Not a recommendation
Adult label context9100-300 mg/day

Health Canada's 2024 natural health product monograph lists 100-200 mg/day for sleep-disturbance label contexts and 150-300 mg/day for healthy mood-balance label contexts in adults. These Canada-specific label contexts and small studies do not establish a general nootropic dose.

06

Timing & effect horizon

Effect horizonUnknown
Unknown
Carbidopa-pretreated kinetics are not effect duration4

The historical kinetics paper studied five healthy volunteers after carbidopa pretreatment and both oral and intravenous 5-HTP. It should not be used as a general oral The time for blood levels to fall by half during the final elimination phase.Source or as evidence for when mood, sleep, calm or nootropic effects start or how long they last.

No reliable public onset or cycle2

A reliable public onset, acute duration or cycle length is not established. Some clinical studies run for weeks, but study duration should not be converted into a supplement cycle or an effect-duration promise.

07

Safety, side effects and risk profile

High interaction risk despite ordinary supplement labels1
5-HTP can combine with serotonergic medicines or supplements in ways that raise serotonin too much. Poison Control highlights antidepressants as a major concern and describes serotonin syndrome as a serious toxicity pattern involving dangerous changes in heart rate, blood pressure and temperature.
Interaction risk9
Confidence: High

Serotonergic combination risk is the dominant safety issue.

Note Health Canada lists a contraindication with antidepressants and a precaution for carbidopa or products with serotonergic activity.

5/5
C
Sedation / impairment9
Confidence: Medium

Drowsiness can occur; driving or machinery context matters.

Note Health Canada labels drowsiness as a possible concern and advises caution while driving or using machinery.

1/5
C
GI discomfort6
Confidence: Medium

Nausea, vomiting, diarrhea and abdominal discomfort are practical tolerability concerns.

Note Dose and powder measurement can affect tolerability.

2/5
B
Headache / dizziness1
Confidence: Medium

Headache, dizziness or agitation-type symptoms can occur and overlap with serotonergic excess.

Note Escalating symptoms should not be normalized as ordinary nootropic adjustment.

2/5
C
Pregnancy / lactation caution9
Confidence: Medium

The Canadian monograph includes a pregnancy and breastfeeding precaution for its non-weight-management use.

Note This is a special-population caution and does not change the low base-risk rating for generally healthy adults.

3/5
C
Evidence uncertainty2
Confidence: High

Benefit claims are narrower and less certain than the serotonin-precursor mechanism suggests.

Note The small and older human evidence base should not be upgraded into clinical, sleep or cognition promises.

3/5
C
Legal / regulatory risk8
Confidence: Medium

U.S. dietary-supplement marketing is not FDA preapproval, and product rules vary by jurisdiction.

Note The FDA source describes U.S. supplement oversight; it does not establish compliance for an individual imported product elsewhere.

1/5
B
08

Interactions and cautions

Interaction check9

Health Canada's 2024 monograph lists a contraindication with antidepressants and a precaution around carbidopa or health products with serotonergic activity, including certain mood-balance supplements, dextromethorphan cough products, pain medicines, nausea medicines and migraine medicines. These combinations are a key safety distinction when comparing 5-HTP.

Alertness9

Health Canada's 2024 monograph notes possible drowsiness and says users should exercise caution while driving or using machinery. This label warning does not establish a reliable sleep benefit or an evening-use schedule.

09

Legal and regulatory status

United States8

As checked on 2026-08-01, the U.S. FDA dietary-supplement framework does not provide premarket approval of supplements for safety or effectiveness. That framework does not determine whether an individual product complies with U.S. requirements.

Canada / supplemented foods10

As of Health Canada's August 15, 2024 decision, 5-HTP was not accepted as a supplemental ingredient in foods because available data were insufficient to establish acceptable conditions of use. This decision applies to the Canadian supplemented-food framework; it does not make a general statement about other Canadian product categories or import status.

10

Practical buying and quality notes

  • Compare capsules by milligrams of actual 5-HTP per capsule and cost per comparable active amount. Compare powders by the stated 5-HTP content, measurement precision and price per gram of active 5-HTP, not only by bag size.3
  • A historical EMS-like illness case was linked to a 5-HTP product that contained an impurity. This case does not establish a current contamination rate or a universal test panel, so bag size or price alone should not be used as quality evidence.7
11

FAQ

Is 5-HTP a nootropic?

3

Not as a focus or productivity enhancer. 5-HTP is better understood as a serotonin-pathway precursor with limited mood and sleep research, high interaction risk and weak direct evidence for healthy cognitive performance.

What 5-HTP dose should I compare on labels?

9

Compare the actual 5-HTP milligrams per serving rather than only Griffonia seed-extract mass. Label ranges are product- and jurisdiction-specific; they do not establish a general nootropic dose.

Why do antidepressant combinations matter?

9

Health Canada's 2024 monograph lists a contraindication with antidepressants and a precaution for products with serotonergic activity. This is why 5-HTP should not be presented as a routine add-on to a serotonin-active regimen.

How long does 5-HTP take to work or need cycling?

4

A clear public onset, acute duration or cycle length is not established. The cited historical kinetics study involved carbidopa-pretreated volunteers, and a study period or label duration should not be converted into a supplement cycle or an effect-duration promise.

Is Griffonia seed extract the same as 5-HTP?

3

Not automatically. Griffonia simplicifolia seed extract is a common commercial source, but labels should state actual 5-HTP content. Compare by milligrams of 5-HTP, not by total seed-extract mass.

What should I check before buying 5-HTP powder?

7

Compare the stated 5-HTP content, serving-size math, measuring precision and storage information. A historical impurity case does not show a current contamination rate, so avoid assuming that bulk size or price indicates product quality.

12

References

  1. Poison Control. 5-HTP Safety Concerns.
  2. Shaw K, Turner J, Del Mar C. Tryptophan and 5-Hydroxytryptophan for depression. Cochrane Database of Systematic Reviews.
  3. Maffei ME. 5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology. Int J Mol Sci. 2020 Dec 26;22(1):181.
  4. Westenberg HG, Gerritsen TW, Meijer BA, van Praag HM. Kinetics of L-5-hydroxytryptophan in healthy subjects. Psychiatry Res. 1982;7(3):373-385.
  5. Sutanto CN, et al. The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial. Clin Nutr. 2024.
  6. Memorial Sloan Kettering Cancer Center. 5-HTP.
  7. Michelson D, et al. An eosinophilia-myalgia syndrome related disorder associated with exposure to L-5-hydroxytryptophan. J Rheumatol. 1994.
  8. U.S. Food and Drug Administration. Information for Consumers on Using Dietary Supplements.
  9. Health Canada. 5-HTP Natural Health Product Monograph. August 28, 2024.
  10. Health Canada. Decision on 5-hydroxytryptophan (5-HTP) as a supplemental ingredient in foods. August 15, 2024.
Note

This page is informational and summarizes available evidence. It is not medical advice, a recommendation, or a substitute for guidance from a qualified clinician.