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2. 5-Hydroxytryptophan (5-HTP)
David Mischoulon, MD, PhD
Director, Depression Clinical and Research Program
Massachusetts General Hospital
Professor of Psychiatry Harvard Medical School

3. 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.

4. Extracted from Griffonia simplicifolia
Studies on 5-HTP are more than 20 years old
Less studied since arrival of SSRIs
Image:
- Iovieno, N. et al. (2011). Second-tier natural antidepressants: review and critique. Journal of Affective Disorders, 130(3), 343–357.

5. Eosinophilia-myalgia syndrome
~ 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.

6. 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
mg / day
3250 mg
/ day
Dosed 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), CD

7. 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.
- Shaw, K. et al. (2002). Tryptophan and 5-hydroxytryptophan for depression. The Cochrane Database of Systematic Reviews, (1), CD

8. 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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