5-HTP
A step between an amino acid and serotonin, taken most often for mood.
- Mood
- Sleep
- Appetite and weight
A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.
On this page
What is 5-HTP?
5-HTP is short for 5-hydroxytryptophan, and it is the step the body takes between tryptophan, an amino acid that arrives in everyday food, and serotonin. Reviewers call that the limiting step: how fast it happens sets how much serotonin the body can make, and further along the same path, how much melatonin. It occurs in nature, and because making it industrially is awkward, most of what is sold is still drawn out of a plant rather than built in a factory; labels usually name that plant as griffonia, or griffonia seed extract. It has a devoted following, and almost everything written about it comes back to mood, sleep and appetite.
Why do people take 5-HTP?
Mood
The thinking. Mood is the reason most people reach for 5-HTP. The thinking is old and simple: low mood has long been linked to low serotonin, and 5-HTP is the thing the body makes serotonin from, converted readily and without the feedback that holds back the step before it.
What research has found. A review pooling the trials found depression scores much lower afterwards, while noting that the studies it gathered were mostly small and that few of them included a placebo group. A crossover trial in 25 adults with Parkinson’s found depression ratings better on 50 mg a day, with apathy scores unchanged. A third trial measured it against a prescribed antidepressant rather than against a placebo, which asks a different question. Research here is still young: a few studies so far, mostly pointing the same way.
Sleep
The thinking. The second thing people take it for is sleep. The idea follows the same chemistry one stop further along: melatonin, the hormone that regulates sleep, is made out of serotonin, so the raw material for one feeds the other, and 5-HTP sits at the head of that line.
What research has found. Two small trials have measured it. Older adults taking 100 mg daily for twelve weeks saw some parts of their sleep scores move and others not, and the change appeared in those who already slept badly rather than those who slept well. In adults with Parkinson’s, time spent in REM sleep rose, while the measures of waking and stirring shifted only slightly and self-ratings improved on the dummy capsule too. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Appetite and weight
The thinking. The third reason is appetite. Reviewers list body weight among the things 5-HTP has been examined for, and the trials were built around fullness rather than the scales: one set out to see whether a supplement could counter hunger while someone was eating less.
What research has found. In a four-week trial, twenty women on a reduced-calorie diet reported less appetite on a griffonia extract while the placebo group’s scores did not move, and BMI and some body measurements differed between them. In an eight-week trial in people who trained regularly, 100 mg a day was followed by a fall in fat mass that differed from placebo, while lean mass, body water and body fat percentage did not change. The studies disagree, so this is unsettled: dose, duration and who took part all seem to shift the result.
What does 5-HTP do in the body?
Swallowed, 5-HTP joins a short chain the body already runs. Tryptophan, an amino acid that arrives in food, is converted into 5-HTP by an enzyme called tryptophan hydroxylase, which comes in two forms. 5-HTP then sheds a small piece of itself and becomes serotonin. Reviewers call the first of those steps the limiting one; the second happens readily, without the feedback that keeps the first in check.
The chain does not stop at serotonin. Further along, serotonin is transformed again into melatonin, which is why one small molecule turns up in writing about mood and about sleep alike. Reviewers place 5-HTP behind a long list of ordinary functions: how people feel, how they behave, how they sleep, how they sense pain, even body temperature. They draw on animal work as well as trials in people, and one notes that 5-HTP behaves awkwardly enough in the body that researchers have looked at slow-release versions of it.
What do people say about taking 5-HTP?
These are anecdotes people have shared, not evidence.
What people like
- Four of these six threads sit in one parenting community, and across all of them a lift in low mood is the commonest thing described.
- Sleep comes up almost as often, usually as a side benefit rather than the reason: falling asleep faster, and sleeping more deeply.
- Several describe the change as gradual rather than dramatic, a heaviness easing over months, or simply fewer bad patches than before.
- A smaller group mention feeling less anxious alongside the mood change, sometimes within the first week of starting.
Common complaints
- Broken, sweaty nights and vivid dreams are the complaint that recurs most, described by a handful of people across two of the threads.
- Some notice nothing at all, and others describe an effect that faded after a few months, ending back with a prescribed medicine.
- One long-term user reports stomach upset and nausea at the larger amounts, and elsewhere people suggest starting well below the amount on the box.
- Whether it sits alongside prescribed antidepressants is the worry that keeps returning, and posters answer each other with warnings about serotonin syndrome.
How people take it
- Amounts described run from 50 mg to 400 mg a day, with several saying 200 mg is a lot to begin on.
- Bedtime is the commonest timing, and people whose sleep it disturbed describe moving the same amount to the morning instead.
- People who have just come off, or are coming off, prescribed antidepressants are a recurring group in these threads.
- Some take it seasonally or only when they feel they need it, one describing autumn through to March rather than all year.
- A few say they raised it with a doctor or psychologist first, and got answers ranging from a recommendation to a discouragement.
Read from these public discussions:
- To consider taking 5-htp (Mumsnet, 2017)
- 5 HTP 200gm (Mumsnet, 2017)
- Anyone used 5-HTP before? (Mumsnet, 2018)
- 5 htp (Mumsnet, 2017)
- I have been using 5 HTP to good effect (Health Rising, 2023)
- 5-htp - Giving It A Try (MyPTSD, 2013)
What forms of 5-HTP are there?
| Form | What’s different | Per serving, on products we list |
|---|---|---|
| 5-HTP | The compound itself, whether the label calls it 5-HTP or names the griffonia seed it came from. | 100 mg |
What else is worth knowing about 5-HTP?
- One review describes 5-HTP as both a medicine in its own right and a natural part of some supplements, and it raises serotonin, which is what several prescribed medicines do. That review covers serotonin syndrome among its subjects, and another describes 5-HTP being taken alongside a prescribed serotonin medicine, where it lifted brain serotonin beyond what the medicine did on its own. For anyone already on such a medicine, this is the thing to raise before starting.
- A review written about when 5-HTP is not suitable concludes that it may not suit some of the very people it is most often suggested to for low mood, and that the claims made for it are not all borne out by the research behind them.
- In one trial of a single dose, roughly one in five of the people given 5-HTP reported tiredness, nausea or being sick. A review of its toxicology also discusses impurities that have turned up in tryptophan and 5-HTP preparations.
- Labels give the amount per serving, and a serving may be more than one capsule. The trials on this page used 50 to 100 mg a day over four to twelve weeks, and one of the appetite trials used a mouth spray of griffonia extract rather than a capsule at all.
If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.
The research behind this page (13 studies)
- Effects of 5-hydroxytryptophan on distinct types of depression: a systematic review and meta-analysis. (2020, meta-analysis)
- Efficacy and safety of 5-hydroxytryptophan on depression and apathy in Parkinson's disease: a preliminary finding. (2020, randomised trial)
- Comparative study of efficacy of l-5-hydroxytryptophan and fluoxetine in patients presenting with first depressive episode. (2013, randomised trial)
- The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial. (2024, randomised trial)
- Preliminary finding of a randomized, double-blind, placebo-controlled, crossover study to evaluate the safety and efficacy of 5-hydroxytryptophan on REM sleep behavior disorder in Parkinson's disease. (2022, randomised trial)
- The Effects of 5-HTP on Body Composition: An 8-Week Preliminary RCT. (2023, randomised trial)
- Relationship between the absorption of 5-hydroxytryptophan from an integrated diet, by means of Griffonia simplicifolia extract, and the effect on satiety in overweight females after oral spray administration. (2012, randomised trial)
- 5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology. (2020, review)
- Adjunctive 5-Hydroxytryptophan Slow-Release for Treatment-Resistant Depression: Clinical and Preclinical Rationale. (2016, review)
- Advances in the Microbial Synthesis of 5-Hydroxytryptophan. (2021, review)
- Molecular basis of 5-hydroxytryptophan synthesis in Saccharomyces cerevisiae. (2016, review)
- 5-HTP efficacy and contraindications. (2012, other)
- Efficient synthesis of 5-hydroxytryptophan in Escherichia coli by bifunctional utilization of whey powder as a substrate for cell growth and inducer production. (2024, review)
How much does 5-HTP cost?
That depends on the form and the pack, so we work out the price of the same dose of every 5-HTP product we can find and rank them.