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5-HTP

5-HTP is the precursor to serotonin, the neurotransmitter sometimes touted to be responsible for happiness. 5-HTP is a simple way to increase brain serotonin levels by bypassing the rate-limiting step, and users reap either the rewards or the hazards of increased brain serotonin.

Our evidence-based analysis on 5-htp features 63 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
Last Updated:

Summary of 5-HTP

Primary information, health benefits, side effects, usage, and other important details

5-HTP is a compound which gets converted into serotonin in the brain. Serotonin is one of the principal neurotransmitters involved in happiness and anti-depression.

5-HTP has been used with success to restore serotonin levels in those that may suffer from decreased serotonin levels, such as the depressed and those with high levels of body inflammation (typically seen in metabolic syndrome).

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How to Take

Recommended dosage, active amounts, other details

A typical dose of 5-HTP is in the range of 300-500 mg, taken either once daily or in divided doses. Lower doses may also be effective, although usually when paired with other substances.

For the purpose of reducing food intake, 5-HTP should be taken with a meal as it increases satiety from food intake (rather than reducing appetite/hunger).

5-HTP should not be taken with any neurological drug that has been prescribed for antidepressant or other cognitive purposes unless cleared by a medical doctor. This is most important for SSRI usage, wherein the combination with 5-HTP is potentially lethal.

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Human Effect Matrix

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The Human Effect Matrix summarizes human studies to tell you what effects 5-HTP has on your body, how much evidence there is, and how strong these effects are.

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-b Notable Very High See all 3 studies
There does appear to be a fairly effective suppression in appetite noted with 5-HTP supplementation in the higher dosage range, which tends to reduce food intake.
grade-b Minor Very High See all 3 studies
The reduction in weight appears to be mostly secondary to a reduction in food intake, and is not too remarkable in magnitude
grade-c Minor - See study
At least one study has noted increased in salivary cortisol following acute ingestion of 5-HTP supplementation.
grade-c Minor - See study
At least one trial suggesting reductions in sleep terrors.

Studies Excluded from Consideration

  • Excluded due to being confounded with Glutamine and Phenylalanine[1]

  • Confounded with a variety of other herbs alongside the one that contains 5-HTP[2][3]

Things to Note

Is a Form Of

Primary Function:

Other Functions:

Also Known As

5-hydroxytryptophan, serotonin precursor

Caution Notice

Although serotonin toxicity has not been observed in humans with coingestion of 5-HTP and anti-depressants, it is advised to consult your doctor if deciding to pair the two.

5-HTP is neurally active by increasing serotonin levels and will be felt, but its actions are more 'euphoric' or happiness inducing rather than stimulatory.

Click here to see all 63 references.