L-5 Hydroxytryptophan (5-HTP): characteristics and uses of this substance

5-hydroxytryptophan or 5-HTP is an important precursor for the human body to form serotonin, a brain neurotransmitter. This compound increases the levels of serotonin in the brain. Serotonin, in turn, plays a key role in the body carrying signals between neurons in the nervous system.

In this article, we’ll see what exactly 5-Hydroxytryptophan is, and learn about its uses, side effects, and effectiveness.

    L-5 Hydroxytryptophan: characteristics

    5-Hydroxytryptophan (5-HTP) is also known as oxytriptan (INN). It is a natural amino acid and a chemical compound precursor and intermediate in the biosynthesis of the neurotransmitters serotonin and melatonin from tryptophan.

    As we have seen, 5-hydroxytryptophan increases serotonin levels in the brain and improves the symptoms of certain pathologies such as depression.

    As for its sale, 5-hydroxytryptophan or 5-HTP is sold as a dietary supplement in the United States and Canada, with actions such as antidepressant, anoretic (appetite suppressant) and helps to reconcile and maintain sleep.

    It is also sold in many European countries as an antidepressant, under the following trade names: Cincofarm, Levothym, Levotonin, Oxyfan, Telesol, Tript-OH and Triptum.

    In terms of efficacy for the treatment of depression, several double-blind clinical trials have demonstrated the efficacy of L-5 Hydroxytryptophan. However, the quality of these studies has been questioned.


      5-hydroxytryptophan it is used as a therapeutic supplement. This substance is not found in food in significant amounts. More precisely, it is an intermediate involved in the metabolism of tryptophan.

      Likewise, tryptophan is an essential amino acid in human nutrition, which It is found in certain foods such as turkey, milk, potatoes, pumpkin and various vegetables.

      5-Hydroxytryptophan is often sold as a dietary supplement and is obtained from the seeds of the legume Griffonia simplicifolia (an African plant). It is usually sold in vegetable capsules or gelatin of 50 mg or 100 mg.


      Several surveys have shown the beneficial effect of hydroxytryptophan L-5 or 5-HTP in pathologies such as primary fibromyalgia, Friedreich’s ataxia, chronic headaches (primary or not), depression, anxiety, compulsive eating associated with obesity and insomnia .

      Risks and side effects

      Although 5-hydroxytryptophan has been studied, it has not been thoroughly studied in a clinical setting; this makes possible side effects and interactions with other drugs not well known.

      On the other hand, it has been observed in laboratory animals that 5-hydroxytryptophan increases the risk of heart valve disease. Although 5-hydroxytryptophan has not undergone a similar experimental protocol, it is known that its conversion to serotonin could cause the same heart damage.

      In addition, 5-hydroxytryptophan taken orally may cause an increase in 5-HIAA in the urine. It is a metabolite of serotonin and indicates that 5-hydroxytryptophan is peripherally metabolized to serotonin and then metabolized to 5-HIAA.

      This can cause a false positive in tests for carcinoid syndrome. This syndrome is mainly caused by the endogenous secretion of serotonin and kallikrein and involves a set of signs and symptoms secondary to a carcinoid tumor. Additionally, it includes flushing, diarrhea, and less commonly heart failure and bronchospasm.


      Some research has attempted to analyze the efficacy, safety and acceptance of L-5 hydroxytryptophan and tryptophan for the treatment of unipolar depression in adults.

      The results of some of them have shown that depressive symptoms may decrease when 5-hydroxytryptophan and tryptophan are compared to a placebo. On the other hand also they involve certain side effects (Which we will see in detail later), and which include symptoms such as dizziness, nausea, and diarrhea.

      In addition, in some cases, the association of tryptophan with the onset of a fatal disease has been reported. However, more evidence is needed to assess the efficacy and safety of these products before firm and meaningful conclusions can be drawn.

      Currently, in terms of pharmacological treatment, antidepressants remain the first choice for treating depression.

      Obviously, the most recommended are those that have no known life-threatening side effects.

      Bibliographical references:

      • Shaw, K., Turner, J. and De la Mar, C. (2002). Tryptophan and 5-hydroxytryptophan for depression. Cochrane.
      • Stahl, SM (2002). Essential psychopharmacology. Neuroscientific bases and clinical applications. Barcelona: Ariel.

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