5-Hydroxytryptophan, commonly called 5-HTP, is a compound your body naturally produces as a stepping stone between the amino acid tryptophan and serotonin, the neurotransmitter that regulates mood, sleep, and appetite. It’s also sold as a dietary supplement, extracted from the seeds of an African plant called Griffonia simplicifolia, and marketed for depression, insomnia, and weight management.
How Your Body Makes and Uses 5-HTP
Every time your body needs serotonin, it starts with tryptophan, an essential amino acid you get from food. An enzyme converts tryptophan into 5-HTP, and then a second enzyme quickly converts 5-HTP into serotonin. That first conversion, tryptophan to 5-HTP, is the bottleneck. It’s the slowest step in the entire process, which is why supplementing with 5-HTP is appealing: it skips past the bottleneck entirely.
5-HTP also crosses from the bloodstream into the brain easily, which tryptophan does not do as efficiently. Tryptophan competes with other amino acids for entry into the brain and can be diverted into producing niacin (vitamin B3) or proteins instead of serotonin. 5-HTP doesn’t get rerouted this way. Once it reaches the brain, it converts directly into serotonin.
Serotonin itself has a second life at night. Your brain converts some of it into melatonin, the hormone that controls your sleep-wake cycle. So raising serotonin levels through 5-HTP can, in theory, support both daytime mood stability and nighttime sleep.
Where 5-HTP Supplements Come From
Commercial 5-HTP is extracted from the seeds of Griffonia simplicifolia, a woody climbing plant native to West and Central Africa. The seeds contain high concentrations of 5-HTP, making them the most practical source for supplement manufacturing. You won’t find meaningful amounts of 5-HTP in common foods. Your body produces it internally from tryptophan-rich foods like turkey, eggs, and cheese, but the supplement form provides it in a concentrated, direct dose.
Mood and Depression
The primary reason people take 5-HTP is to boost serotonin levels in the brain, which plays a central role in mood regulation. The logic mirrors how common antidepressants work: SSRIs keep serotonin active longer at nerve connections, while 5-HTP aims to increase the total supply of serotonin available. Some clinical studies have shown improvements in depressive symptoms with 5-HTP supplementation, though the evidence base is smaller and less rigorous than what exists for prescription antidepressants. It remains a popular option among people looking for a non-prescription approach to low mood.
Appetite and Weight
5-HTP appears to reduce caloric intake by triggering earlier feelings of fullness. In one study, obese women who took 5-HTP for 35 days ate less, lost weight, and reported feeling full sooner during meals, without consciously trying to diet. A separate trial found that participants in the 5-HTP group consumed roughly 500 fewer calories per day than a control group, again without deliberately restricting food.
The effect seems particularly strong for carbohydrate cravings. In a study of people with diabetes, those taking 5-HTP reduced their overall calorie intake, and about 75% of the reduction came specifically from carbohydrates, with the remaining 25% from fats. Brain imaging research has confirmed that 5-HTP activates regions associated with satiety and appetite suppression, which aligns with what participants report feeling.
Sleep
Because serotonin is the raw material your brain uses to make melatonin, 5-HTP may help with sleep by supporting that natural conversion process. Serotonin promotes wakefulness and emotional stability during the day, then gets converted into melatonin as darkness signals bedtime. If serotonin levels are low, melatonin production can suffer, potentially disrupting your ability to fall asleep or maintain a normal sleep-wake rhythm. Some people take 5-HTP in the evening for this reason, though clinical data specifically measuring sleep improvements from 5-HTP is limited compared to direct melatonin supplementation.
Safety Risks and Drug Interactions
The most serious risk with 5-HTP is serotonin syndrome, a potentially dangerous condition that occurs when serotonin levels climb too high. Symptoms start with agitation, rapid heartbeat, and muscle spasms, and can progress to rigidity, high fever, and seizures. This is most likely to happen when 5-HTP is combined with other substances that raise serotonin.
Medications that should not be taken with 5-HTP include:
- SSRIs (common antidepressants like fluoxetine and sertraline)
- MAOIs (an older class of antidepressants)
- Tricyclic antidepressants and structurally similar drugs, including some muscle relaxants
A documented case report described a patient who developed serotonin syndrome after combining 5-HTP with a muscle relaxant that is structurally similar to tricyclic antidepressants. The patient experienced muscle spasms, limited movement, agitation, and eventually seizures and dangerously high body temperature.
On the milder end, 5-HTP commonly causes gastrointestinal discomfort, including nausea. This happens because serotonin receptors line the gut, and increasing serotonin production doesn’t limit itself to the brain. Starting with a low dose and taking it with food can reduce stomach upset.
The Peak X Contamination Concern
In the late 1990s, researchers identified a family of contaminants collectively called “Peak X” in commercially available 5-HTP supplements. These contaminants were linked to symptoms resembling eosinophilia-myalgia syndrome, a serious condition involving muscle pain and an abnormal increase in certain white blood cells. Lab analysis of eight different commercial 5-HTP products found that all of them contained three or more contaminants from the Peak X family. This history is worth knowing because 5-HTP, as a dietary supplement, is not regulated with the same rigor as prescription drugs. Choosing products from manufacturers that conduct third-party testing can reduce, though not eliminate, the risk of contaminant exposure.
How 5-HTP Differs From L-Tryptophan
Both 5-HTP and L-tryptophan are sold as supplements aimed at boosting serotonin, but they enter the production line at different points. L-tryptophan still needs to pass through the slow, rate-limiting enzyme step to become 5-HTP before it can become serotonin. It also competes with other large amino acids to cross into the brain, and some of it gets diverted into making niacin or building proteins instead of serotonin. 5-HTP bypasses all of that. It crosses into the brain without competition and converts to serotonin in a single, fast step. This makes it a more direct precursor, though “more direct” doesn’t automatically mean better or safer for every person.