Is 5-HTP Effective as a Weight-reducing Supplement?

Known for its antidepressant actions, the amino acid, 5-HTP (oxitriptan) has recently come into sharp focus because of its appetite-suppressant action. Although touted as a weight-loss supplement, many are sceptical of its weight-reducing abilities. Let us investigate.


5-HTP or 5-hydroxytryptophan (also known as oxitriptan) is an amino acid derived from natural sources. It is an intermediate metabolite formed during the synthesis of neurotransmitters – serotonin (5-hydroxytryptamine, 5-HT) and melatonin – from the amino acid tryptophan.

It is derived from Griffonia simplicifolia, a woody shrub indigenous to the rain forests, especially of West Africa (Hoy, Ferdinand, & Harrison, 1974; Lamb, Shibata, & Goldstein, 1983).

Although present in food in minute amounts, tryptophan – the amino acid closely related to 5-HTP – is found in green veggies, milk and meat (Web Archive, 2013).

In the past, 5-HTP has gained prominence as an antidepressant. However, more recently, its appetite suppressant action has come into sharp focus. 5-HTP has, therefore, gained popularity as a weight loss supplement as well.

Let us dig deeper into research to see if these alleged weight-reducing abilities of 5HTP have indeed been proven.

How Does 5-HTP Cause Fat Loss?

5-HTP apparently helps fat loss by suppression appetite. Very few clinical studies investigation the correlation between 5-HTP and weight-loss have, however, been conducted (Cangiano et al., 1998; Cangiano et al., 1992; Cangiano et al., 1991) (esp. when compared to those concerning effectiveness of 5-HTP in depression).

These studies reported that supplementation with 5-HTP resulted in consumption of fewer calories and improvement in macronutrient content of food. What is surprising is that the study participants exhibited these behaviour traits despite not trying to be strict with their diets. The authors of the study believed that these changes were likely due to the improved satiety experienced by users of 5-HTP, even on consumption of fewer calories (Cangiano et al., 1998; Cangiano et al., 1992; Cangiano et al., 1991).

The study also reported that the doses of 5-HTP needed to induce weight-loss were quite high; most participants reported nausea.

Other Uses of 5-HTP

As stated earlier, 5-HTP is recommended for treatment of depression (Shaw, Turner, & Del, 2001). Although some clinical studies have demonstrated the efficacy of 5-HTP in relieving depression (Turner & Blackwell, 2005)some researchers believe that larger trials are needed to effectively prove the connection (University of Maryland, 2013).

Other suggested uses of 5-HTP are fibromyalgia, headaches (especially those associated with migraine) and insomnia (inability to sleep).

It has to be noted here, however, that the evidences for effectiveness of 5-HTP in these conditions is equivocal (University of Maryland, 2013).

Adverse Effects of 5-HTP

Presence of a contaminant called the ‘Peak X’ was reported in both 5-HTP and tryptophan supplements. Peak X, it was believed, was responsible for the Eosinophilic Myalgia Syndrome (EMS) associated with the use of these supplement. EMS affects skin, blood, muscles and organs and has the potential to be fatal.

The high incidence of EMS amongst tryptophan supplement users led to the withdrawal of these supplements. A somewhat similar syndrome is observed (very rarely though) with the use of 5-HTP supplements.

Additionally, the high doses of 5-HTP needed (as mentioned earlier) to induce even a minor reduction in body weight are associated with side-effects like nausea.

Take Home Message

In a nutshell, it appears that 5-HTP does possess an appetite suppressant action. However, the evidence in favour (in terms of number of studies conducted) appears to be very week. Also, the likelihood of adverse effects (some potentially fatal) makes the justification of use of 5-HTP in weight-loss supplements very feeble.

To conclude, 5-HTP – at the present moment – shouldn’t be your choice and you should be way of using any weight-loss supplement containing it.

Reference List

  • Cangiano, C., Ceci, F., Cairella, M., Cascino, A., Del, B. M., Laviano, A. et al. (1991). Effects of 5-hydroxytryptophan on eating behavior and adherence to dietary prescriptions in obese adult subjects. Adv.Exp.Med Biol., 294, 591-593.
  • Cangiano, C., Ceci, F., Cascino, A., Del, B. M., Laviano, A., Muscaritoli, M. et al. (1992). Eating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-hydroxytryptophan. Am J Clin Nutr., 56, 863-867.
  • Cangiano, C., Laviano, A., Del, B. M., Preziosa, I., Angelico, F., Cascino, A. et al. (1998). Effects of oral 5-hydroxy-tryptophan on energy intake and macronutrient selection in non-insulin dependent diabetic patients. Int J Obes Relat Metab Disord, 22, 648-654.
  • Hoy, T. G., Ferdinand, W., & Harrison, P. M. (1974). A computer-assisted method for determining the nearest integer ratios of amino acid residues in purified proteins. Int J Pept.Protein Res., 6, 121-140.
  • Lamb, J. E., Shibata, S., & Goldstein, I. J. (1983). Purification and Characterization of Griffonia simplicifolia Leaf Lectins. Plant Physiol, 71, 879-887.
  • Shaw, K., Turner, J., & Del, M. C. (2001). Tryptophan and 5-hydroxytryptophan for depression. Cochrane.Database.Syst.Rev, CD003198.
  • Turner, E. H. & Blackwell, A. D. (1-1-2005). 5-Hydroxytryptophan plus SSRIs for interferon-induced depression: Synergistic mechanisms for normalizing synaptic serotonin. Medical hypotheses 65[1], 138-144.
    Ref Type: Abstract
  • University of Maryland, M. C. (2013). 5-Hydroxytryptophan (5-HTP). Source: Online Ref
  • Web Archive. (2013). 5-Hydroxytryptophan (5-HTP). Source: Online Ref

Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.

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