Supplement
5-HTP is a compound the body makes from the amino acid tryptophan and then converts into serotonin, a chemical messenger that helps shape mood, sleep, and appetite. Most people look at it for appetite control, and the evidence is moderate: in people with obesity, appetite went down, and weight loss followed the smaller appetite. The studies were small, though, and the weight findings remain limited.
Sources: PMID 9705024; PMID 1384305
- Updated
- How we grade
- 9 studies cited
- Best evidence
- Grade B
- Conditions studied
- 7
- Outcomes
- 11
- Graded outcomes
- 0241
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Depression Symptoms Moderate improvement in depression symptoms | Improves (the measure goes down) | Moderate effect | 4 studies | 133 people | ||
Studies that measured depression symptoms
| ||||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Appetite Moderate decrease in appetite | Improves (the measure goes down) | Moderate effect | 1 study | 39 people | ||
| Weight Weight loss secondary to reduced appetite | Improves (the measure goes down) | Small effect | 2 studies | 39 people | ||
Type 2 Diabetes
- Appetite: improves
- Weight: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Appetite Reduced appetite in diabetics leading to weight loss | Improves (the measure goes down) | Moderate effect | 1 study | 25 people | ||
| Weight | Changes; see studies | 2 studies | 25 people | |||
Sleep Terrors
- Sleep Terror Frequency: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Sleep Terror Frequency Reduced frequency of sleep terrors in children | Improves (the measure goes down) | Moderate effect | 1 study | 45 people | ||
Studies that measured sleep terror frequency | ||||||
Weight Loss & Maintenance
- Appetite: improves
- Weight: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Appetite Moderate Decrease | Improves (the measure goes down) | Moderate effect | 1 study | 20 people | ||
| Weight | Changes; see studies | 2 studies | 20 people | |||
Parkinson's Disease
- Apathy
- Depression Symptoms: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Apathy No effect on apathy in Parkinson's | NoneNo effect | 25 people | ||||
| Depression Symptoms | Changes; see studies | 4 studies | 25 people | |||
Studies that measured depression symptoms
| ||||||
Panic Disorder
- Cortisol: changes; see studies
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cortisol | Changes; see studies | 1 study | 48 people | |||
Studies that measured cortisol | ||||||
What the published studies found
1 automated reading
Mood
The studies read are too weak to tell whether 5-HTP changes mood. They lean toward an improvement, which is not enough to claim one. The evidence is very weak.
4 studies counted of 9 read: 4 trials (80 people in the trials).
- Randomised trial, 2025; 30 people; singaporean older adults: improves.
GDS score improved in the 5-HTP group
The Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function and Mood in Singapore Older Adults: A Randomized Controlled Trial - Crossover trial, 2014; 24 people; 24 healthy individuals: no clear difference.
as were ratings of mood, hunger, and stool urgency
The effects of 5-hydroxytryptophan in combination with different Fatty acids on gastrointestinal functions: a pilot experiment - Randomised trial, 1983; 26 people: improves.
reduction in HRSD scores, showing 0.05 significance
Treatment of depression with L-5-hydroxytryptophan combined with chlorimipramine, a double-blind study - Randomised trial, 1976: improves.
act primarily on mood, and unequivocally in the direction of elation
Intravenous L-5-hydroxytryptophan in normal subjects: an interdisciplinary precursor loading study. Part II: profile of psychotropic effects derived from protocols and psychometric investigations
- Randomised trial, 2025; 30 people; singaporean older adults: improves.
Key findings
- Depression SymptomsImproves (the measure goes down)
- AppetiteImproves (the measure goes down)
- WeightImproves (the measure goes down)
Shop the evidence-backed picks
Third-party tested 5-HTP products, in the forms the graded studies used where we can match them.
- Grade B
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Studies cited
9 studies from PubMed
- The effects of oral 5-hydroxytryptophan administration on feeding behavior in obese adult female subjects
- Eating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-hydroxytryptophan
- L -5-Hydroxytryptophan treatment of sleep terrors in children
- Effects of oral 5-hydroxy-tryptophan on energy intake and macronutrient selection in non-insulin dependent diabetic patients
- L-5-hydroxytryptophan induced increase in salivary cortisol in panic disorder patients and healthy volunteers
- Effects of 5-hydroxytryptophan on distinct types of depression: a systematic review and meta-analysis.
- Comparative study of efficacy of l-5-hydroxytryptophan and fluoxetine in patients presenting with first depressive episode.
- A functional-dimensional approach to depression: serotonin deficiency as a target syndrome in a comparison of 5-hydroxytryptophan and fluvoxamine.
- Efficacy and safety of 5-hydroxytryptophan on depression and apathy in Parkinson's disease: a preliminary finding.