What is it?
5-HTP is used by the human body to make serotonin, an important substance for normal nerve and brain function. Serotonin appears to play significant roles in sleep, emotional moods, pain control, inflammation, intestinal peristalsis, and other body functions.1
Where is it found?
5-HTP is not present in significant amounts in a typical diet. The human body manufactures 5-HTP from L-tryptophan, a natural amino acid found in most dietary proteins. However, eating food that contains L-tryptophan does not significantly increase 5-HTP levels. Supplemental 5-HTP is naturally derived from the seeds of Griffonia simplicifolia, a West African medicinal plant.
Why do dieters use it?*
Some dieters say that 5-HTP
- helps suppress appetite.
- helps promote weight loss.
What do the advocates say?*
Known for its ability to promote weight loss, 5-HTP has been shown to reduce appetite. It appears to do this by stimulating serotonin production in the brain. While 5-HTP has not yet been extensively researched, some human and double-blind studies have shown that 5-HTP promotes weight loss.
How much is usually taken by dieters?
Appetite reduction and weight loss (averaging 11 pounds in 12 weeks) has occurred with amounts of 600 to 900 mg daily. In another clinical trial, 750 mg per day has been shown to be effective at decreasing carbohydrate and fat intake and promoting weight loss.
Are there any side effects or interactions?
During the clinical trials described above, some people taking large amounts of 5-HTP experienced gastrointestinal upset (e.g. nausea) or, less often, headache, sleepiness, muscle pain, or anxiety.
A substance known as “Peak X” has been found in low concentrations in several over-the-counter 5-HTP preparations. Some researchers think this substance may be linked2 3 4 to toxicity previously reported5 6 7 in a 1989 L-tryptophan contamination incident. However, there is serious question about whether Peak X is actually the toxic agent and it may be unrelated to the problems previously associated with L-tryptophan.8 9 10 11 12 13 14 15 Although two articles reported possible associations between 5-HTP consumption and toxicity symptoms similar to those attributed to contaminated L-tryprophan,16 17 evidence linking 5-HTP or Peak X with any toxicity symptoms remains speculative. Although the structure of Peak X has recently been identified, there is no firm evidence that this substance has caused or contributed to any toxicity or disease.18
Very high intakes of 5-HTP have caused muscle jerks in guinea pigs19 and both muscle jerks20 and diarrhea in mice.21 Injected 5-HTP has also caused kidney damage in rats.22 To date, these problems have not been reported in humans. “Serotonin syndrome,” a serious but uncommon condition caused by excessive amounts of serotonin, has not been reported to result from supplementation with 5-HTP; in theory it could be triggered by the supplement.23 However, the level of intake at which this toxic effect might potentially occur remains unknown.
5-HTP should not be taken with antidepressants, weight-control drugs, other serotonin-modifying agents, or substances known to cause liver damage, because in these cases 5-HTP may have excessive effects. People with liver disease may not be able to regulate 5-HTP adequately and those suffering from autoimmune diseases such as scleroderma may be more sensitive than others, to 5-HTP.24 These people should not take 5-HTP without consulting a knowledgeable healthcare professional. The safety of taking 5-HTP during pregnancy and breast-feeding is not known at this time.
Are there any drug
interactions?
Certain medicines may interact with 5-hydroxytryptophan. Refer to drug interactions for a list of those medicines.
*Dieters and weight-management advocates may claim benefits for 5-HTP based on their personal or professional experience. These are individual opinions and testimonials that may or may not be supported by controlled clinical studies or published scientific articles on 5-HTP. For more complete and detailed information, including references and safety information, see 5-HTP as a nutritional supplement.
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24. Sternberg EM, Van Woert MH, Young SN, et al. Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa. N Engl J Med 1980;303:782–7.