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5-Hydroxytryptophan (5-HTP) David Mischoulon, MD, PhD Director, Depression Clinical and Research Program Massachusetts General Hospital Professor of Psychiatry Harvard Medical School

5-Hydroxytryptophan: Introduction 5-HTP Serotonin Iovieno, N. et al. (2011). Second-tier natural antidepressants: review and critique. Journal of Affective Disorders, 130(3), 343–357.

Extracted from Griffonia simplicifolia Studies on 5-HTP are more than 20 years old Less studied since arrival of SSRIs Image: https://nootripure-0abenxpuikiuu2s.netdna-ssl.com/wp-content/uploads/sites/6/2018/04/Griffonia.jpg - Iovieno, N. et al. (2011). Second-tier natural antidepressants: review and critique. Journal of Affective Disorders, 130(3), 343–357.

Eosinophilia-myalgia syndrome 1989 - 1990 ~ 1500 cases At least 38 deaths Banned by the United States FDA Contamination was the result of bad manufacturing standards 5-HTP 5-HTP back on the market Iovieno, N. et al. (2011). Second-tier natural antidepressants: review and critique. Journal of Affective Disorders, 130(3), 343–357.

Studies on 5-HTP and Depression Small sample size 6 Showing statistical significance Vs Placebo 27 studies published Doses 1 -2 studies rigorous enough 20 mg / day 200 - 300 mg / day 3250 mg / day Dosed 3 - 4 times a day Half-life: 4 hours - Iovieno, N. et al. (2011). Second-tier natural antidepressants: review and critique. Journal of Affective Disorders, 130(3), 343–357.   - Shaw, K. et al. (2002). Tryptophan and 5-hydroxytryptophan for depression. The Cochrane Database of Systematic Reviews, (1), CD003198.

Safety Common side effects Nausea Vomiting Diarrhea Cases of serotonin syndrome when combined with SSRIs or MAOIs Use with caution - Iovieno, N. et al. (2011). Second-tier natural antidepressants: review and critique. Journal of Affective Disorders, 130(3), 343–357. https://doi.org/10.1016/j.jad.2010.06.010   - Shaw, K. et al. (2002). Tryptophan and 5-hydroxytryptophan for depression. The Cochrane Database of Systematic Reviews, (1), CD003198.

Key Points 5-hydroxytryptophan may be an effective antidepressant working through stimulation of serotonergic mechanisms. Although once banned by the FDA for associated toxic reactions, 5-HTP is currently back on the market and considered safe with current manufacturing standards. Since the 1980s, there has been limited research on 5-HTP for depression and new studies are needed.

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