The most useful number about 5-HTP comes from a Cochrane review that searched the whole literature and found 108 trials. Only 2 of them were good enough to use.
Those 2 trials covered 64 patients between them. Everything written about 5-HTP and mood rests on a base that small, and this guide starts there.
Quick Answer: What Is 5-HTP?
5-HTP is 5-hydroxytryptophan, the intermediate your body makes from the amino acid tryptophan on the way to serotonin and then melatonin. As a supplement it is taken for mood, sleep and appetite. The evidence is thinner than its reputation: a Cochrane review located 108 trials and found only 2 of sufficient quality, involving 64 patients in total.
Key Takeaways
- 5-HTP is the step between tryptophan and serotonin in 1 pathway.
- Cochrane located 108 trials and could use only 2 of them.
- Those 2 trials covered 64 patients, which is a very small base.
- The 2024 sleep trial used 100 mg daily, exactly 1 of our capsules.
- Never combine it with an antidepressant without a clinician, for 1 serious reason.
Related Products
What It Actually Is
5-HTP is not a herb and not a vitamin. It is a molecule your own body produces, sitting at 1 specific point in a chain.
- The chain: Tryptophan, then 5-HTP, then serotonin, then melatonin.
- The bottleneck: Making 5-HTP is the limiting step in that chain.
- Source: Commercial 5-HTP comes from Griffonia simplicifolia seeds.
- Our bottle: 100 mg per vegan capsule, 30 per bottle.
Because the conversion from tryptophan is the rate-limiting step, supplying 5-HTP directly bypasses it, which is the entire pharmacological argument for the supplement.[1]5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology — International Journal of Molecular Sciences (2020) View source A clean mechanism is not the same as a clean evidence base, and the 100 mg in our capsule is also the exact daily amount used in the most recent trial, covered in 5-HTP for sleep.
The Number That Frames Everything
A Cochrane review set out to answer whether 5-HTP and tryptophan beat placebo for depression, and what it found in the literature matters more than what it found in the data.
| What the review did | Result |
|---|---|
| Trials located by the search | 108 |
| Trials of sufficient quality to include | 2 |
| Total patients in those 2 trials | 64 |
| Peto odds ratio versus placebo | 4.10, 95% CI 1.28 to 13.15 |
| Number needed to treat | 2.78 |
| Reviewers' verdict on the evidence | Insufficient quality to be conclusive |
The odds ratio looks impressive and the confidence interval runs from 1.28 to 13.15, which tells you how few people generated it.[2]Tryptophan and 5-hydroxytryptophan for depression — Cochrane Database of Systematic Reviews (2002) View source The reviewers wrote that few of the many studies were reliable enough to use. What that means for mood specifically is worked through in 5-HTP for anxiety and mood.
What It Is Taken For, Graded
Four uses account for almost all the search traffic, and they do not deserve equal confidence.
| Use | Best human evidence | Honest grade |
|---|---|---|
| Sleep quality | 2024 RCT, 30 older adults, 100 mg, 12 weeks | Promising in poor sleepers only |
| Panic and anxiety | 24 panic disorder patients, 200 mg | Positive in diagnosis, not in health |
| Depression | Cochrane, 2 usable trials, 64 patients | Too thin to be conclusive |
| Weight loss | 27 women, sublingual spray, not capsules | Not evidence for a capsule |
Row 4 is the one that surprises people. The satiety trial used plant extracts naturally containing 5-HTP delivered as a sublingual spray five times a day, which is not the product anyone is buying.[3]Satiety and amino-acid profile in overweight women after a new treatment using a natural plant extract sublingual spray formulation — International Journal of Obesity (2009) View source
The Sleep Finding, Stated Precisely
The cleanest 5-HTP-only sleep trial is recent and used exactly the amount in our capsule.
- Design: 12-week randomized trial, single-blinded.
- People: 30 older adults, aged 66 on average.
- Dose: 100 mg of 5-HTP daily.
- Result: Poor sleepers improved, and good sleepers did not.
Serum serotonin rose, and the control arm simply did not take anything rather than taking a placebo, which is a real limitation.[4]The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial — Clinical Nutrition (2024) View source Twelve weeks is also longer than most people give a supplement before deciding.
The Interaction You Cannot Ignore
This is the part of 5-HTP that genuinely matters, and it is not a mild caution.
- The mechanism: More serotonin on top of a drug that already raises it.
- The risk: Serotonin syndrome, which can be an emergency.
- Named drugs: SSRIs, SNRIs, MAOIs, tricyclics, triptans, tramadol, linezolid.
- Herbal too: St John's wort belongs on that list.
A published case attributes serotonin syndrome to the combination of linezolid and 5-HTP, so this is documented rather than theoretical. The full list is in side effects and drug interactions.
Where a 100 mg Capsule Fits
Set against those trials, a capsule has a narrow and honest place.
- Not on medication: The first requirement, without exception.
- Sleep quality: The 1 use with a recent dose-matched trial.
- Short trial: 30 capsules is a defined 30-day test.
- Not for depression: That is a clinical conversation.
On those terms a 100 mg capsule is a reasonable thing to try and a poor thing to self-prescribe against a diagnosis.
Contact a Clinician or Emergency Services Rather Than Starting This If
- Agitation, confusion, fast heartbeat, sweating, tremor or a high temperature after combining it with any serotonergic medicine, which can indicate serotonin syndrome
- Taking an SSRI, SNRI, MAOI, tricyclic, triptan, tramadol, linezolid or St John's wort
- Any thought of self-harm, which is a same-day clinical contact rather than a supplement question
- Reducing or stopping a prescribed antidepressant in order to try this instead
- Severe unexplained muscle pain with fatigue, given the history of this ingredient class
Frequently Asked Questions
What does taking 5-HTP do for you? +
It supplies the intermediate your body converts to serotonin. In a 2024 trial of 30 older adults taking 100 mg daily, poor sleepers improved their sleep score and good sleepers did not.
Does 5-HTP treat depression? +
The evidence does not support that. A Cochrane review found 108 trials and only 2 of sufficient quality, covering 64 patients, and called the evidence insufficient to be conclusive.
Does 5-HTP improve your mood? +
Some people report that, and the controlled evidence is thin. The 1 clear anxiety finding appeared in diagnosed panic disorder and produced no effect in 24 healthy volunteers.
Does 5-HTP help with weight loss? +
The satiety trial people cite used a sublingual spray five times a day in 27 women, not a capsule. It is not evidence for the product on this page.
Is it safe to take 5-HTP every day? +
For someone on no serotonergic medication, short daily use is what the trials did, over 4 to 12 weeks. The interaction list matters far more than the duration.
What should you not mix 5-HTP with? +
SSRIs, SNRIs, MAOIs, tricyclics, triptans, tramadol, linezolid and St John's wort. Combining them risks serotonin syndrome, which is 1 medical emergency.
Is 5-HTP restricted the way L-tryptophan was? +
No. L-tryptophan was withdrawn in 1989 after an outbreak traced to contaminated material from a single manufacturer, and the 2 substances get confused.
Is 5-HTP a recognised medical treatment? +
No. Of 108 located trials, 2 were usable, which is not a base any prescriber can work from whatever the mechanism suggests.
How long does it take for 5-HTP to kick in? +
The sleep trial ran 12 weeks and the panic study used a single 200 mg dose. There is no reliable 1-day answer, and 4 weeks is the sensible minimum test.
What are the main risks of 5-HTP? +
There are 2: the interaction risk, and nausea, which is the most commonly reported effect. Neither is a reason for alarm on its own.
Related Reading
Related Products
