5-hydroxytryptophan (5-HTP)


5-HTP or 5-hydroxytryptophan, is a naturally occurring amino acid, used by the body in the synthesis of the neurotransmitter, serotonin. Serotonin is commonly known as the body’s ‘feel good’ chemical, but it has many other uses in the body other than to reward us with a good feeling when we do something positive towards our survival, like eating or exercise1,2. Serotonin is actually more common outside of the brain, found mainly in the gastrointestinal tract, involved in regulation of intestinal movements3. Low serotonin levels have been implicated many times in the study of depression, and is the focus of many anti-depressants4,5. Serotonin is also linked to sleep regulation, confirming links between depression and insomnia6-8.

As a supplement

5-HTP has been shown to be well absorbed, and is known to be readily converted into serotonin in the brain9. It is thought to aid in a few different ways, outlined below. Due to its short life in the body, it is suggested to be more effective when taken multiple times throughout the day, rather than in one big dose10,11.

Weight loss

Studies have shown 5-HTP may increase feelings of fullness, aiding with weight loss, by counteracting hormones that increase appetite12,13.


Many studies and reviews have shown positive results for 5-HTP in the treatment of depression, and a lot of people think it has been extremely helpful for treating their depression14-16. However, the research has been mixed, with some studies seeing quite significant efficacy, but seemingly not any better than the placebo17. If 5-HTP is going to get serious backing as a treatment for depression, it is going to need many more studies.

Headaches and migraines

5-HTP has been shown to be an effective treatment of migraines in various studies, specifically with the intensity of migraines18-20. Low serotonin levels are thought to be a potential cause of migraines21.

Sleep aid

Serotonin, synthesised from 5-HTP, can be converted to melatonin - a hormone involved in regulating sleep22. Higher levels of melatonin increase feelings of tiredness and promote sleep. Various studies have shown 5-HTP as an effective treatment for insomnia, especially when combined with another sleep promoting neurotransmitter, GABA22,23. Vitbox is planning on stocking GABA soon, including it in our coming sleep aid supplement.


There are potential negative interactions with 5-HTP and some sleep aid/antidepressant medications, so consult your doctor before taking 5-HTP if you take other medications. Some people may react more strongly to 5-HTP, so try 1 a day of a low dose first, and if you don't experience any side effects for a few days, then you can try upping the dose. Please consult your doctor if you are unsure, as vitbox cannot be held accountable for any side effects experienced.

  1. Structure and Function of the Brain Serotonin System. (Jacobs, 1992)
  2. Neuromodulation of Aerobic Exercise—A Review. (Heijnen, 2016)
  3. The Expanded Biology of Serotonin, (Berger, 2009)
  4. Role of serotonin in the pathophysiology of depression: focus on the serotonin transporter. (Owens, 1994)
  5. Antidepressants. (Frazer, 1997)
  6. Comorbidity of insomnia and depression. (Staner, 2010)
  7. Serotonin and sleep. (Ursin, 2002)
  8. APD125, a Selective Serotonin 5-HT2A Receptor Inverse Agonist, Significantly Improves Sleep Maintenance in Primary Insomnia. (Rosenberg, 2008)
  9. 5-Hydroxytryptophan: a clinically-effective serotonin precursor. (Birdsall, 1998)
  10. Kinetics of l-5-hydroxytryptophan in healthy subjects. (Westenberg, 1982)
  11. Adjunctive 5-hydroxytryptophan slow-release for treatment-resistant depression: Clinical and pre-clinical rationale. (Jacobsen, 2016)
  12. Eating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-hydroxytryptophan. (Cangiano, 1992)
  13. A Functional Food Product for the Management of Weight. (Bell, 2010)
  14. l-5-Hydroxytryptophan in depression: the first substitution therapy in psychiatry? The treatment of 99 out-patients with 'therapy-resistant' depressions. (Hiele, 1980)
  15. An Open-Label Pilot Study of Combined Augmentation With Creatine Monohydrate and 5-Hydroxytryptophan for Selective Serotonin Reuptake Inhibitor- or Serotonin-Norepinephrine Reuptake Inhibitor-Resistant Depression in Adult Women. (Kious, 2017)
  16. Tryptophan and 5-hydroxytryptophan for depression. (Shaw, 2002)
  17. 5-Hydroxytryptophan versus methysergide in the prophylaxis of migraine. Randomized clinical trial. (Titus, 1986)
  18. 5-HTP efficacy and contraindications. (Hinz, 2012)
  19. Treatment of essential headache in developmental age with L-5-HTP (cross over double-blind study versus placebo). (Longo, 1984)
  20. 5-Hydroxytryptophan in the prophylaxis of migraine. (Sicuteri, 1972)
  21. Serotonin and Migraine: Biology and Clinical Implications. (Hamel, 2007)
  22. The International Journal of Biochemistry & Cell Biology, Melatonin, 8(38) (Hardeland, 2006)
  23. Sleep-promoting effects of a GABA/5-HTP mixture: Behavioral changes and neuromodulation in an invertebrate model. (Hong, 2016)

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