Tryptophan

Tryptophan is an essential amino acid, and is a precursor of the neurotransmitter serotonin. L-tryptophan has been used as a dietary supplement to help relieve insomnia and depression.

Importance to ME/CFS
By mediating tryptophan catabolism, the enzyme indoleamine 2,3-dioxygenase (IDO) has a complex role in immunoregulation in infection and autoimmunity. Ron Davis, speaking about tryptophan being available on the market, has made it clear that self experimentation can be very dangerous. There is insufficient evidence for the use of L-tryptophan to improve sleep or depression.

Learn more
The 15th Conference of the International Society of Tryptophan Research was held at The University of Shiga Prefecture, which is situated in Hikone city, 30 miles east of Kyoto. The conference was a venue for tryptophan research including cancer, immunology, neuroscience, pathology, pharmacology, physiology, clinical diagnosis, nutrition, food science, analytical chemistry and L- tryptophan metabolism.

Notable studies

 * 2010, Sex differences in plasma prolactin response to tryptophan in chronic fatigue syndrome patients with and without comorbid fibromyalgia (Full text)
 * 2011, Kynurenine pathway Hypothesis: The nature of the chronic Fatigue syndrome (cFs) Revisited (Full text)
 * 2012, A Brief Historic Overview of Clinical Disorders Associated with Tryptophan: The Relevance to Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) (Full text)
 * 2014, Tryptophan depletion in chronic fatigue syndrome, a pilot cross-over study (Full text)
 * 2014, Biological phenotypes underpin the physio-somatic symptoms of somatization, depression, and chronic fatigue syndrome (Abstract)
 * 2014, Physiosomatic complaints, immune-inflammatory pathways, and serotonin-related mood symptoms: relevance for tryptophan-related challenge procedures and clinical considerations with respect to the DSM-V (Comment on 2014, "Biological phenotypes underpin...")
 * 2016, The Many Neuroprogressive Actions of Tryptophan Catabolites (TRYCATs) that may be Associated with the Pathophysiology of Neuro-Immune Disorders (Abstract)