By Jennifer Copley (Last Updated 4 February 2015)
Tryptophan (also known as L-Tryptophan) is an essential amino acid (protein building block). It’s called essential because people need it but their bodies can’t produce it, so they must get it from food or supplements. For the body to use tryptophan properly, it also requires sufficient iron, riboflavin, and vitamin B6.
Tryptophan is a precursor of the neurotransmitter serotonin, a brain chemical involved in mood regulation. Some experts believe that tryptophan can reduce anxiety and improve mood.
Does Tryptophan Reduce Anxiety?
Some studies indicate that depletion of tryptophan can increase anxiety (Robinson et al., 2012), and that increasing tryptophan may reduce anxiety (Hudson et al., 2007; Schruers et al., 2002). Overall, evidence suggests that tryptophan deficiency may cause anxiety, depression, difficulty concentrating, insomnia, and irritability (The George Mateljan Foundation, 2012).
Although a handful of studies have yielded promising results, the effectiveness of tryptophan for anxiety, depression, and sleep problems has not been proven and more research is required. Additional conditions for which tryptophan may provide benefits include premenstrual dysphoric disorder (a severe form of PMS) and quitting smoking (WebMD, 2012), so it may help with anxiety indirectly for some people by treating certain anxiety-inducing problems.
Are Tryptophan Supplements Dangerous?
Two decades ago, tryptophan supplements were removed from the market after many people became ill with eosinophilia-myalgia syndrome, leading to 37 deaths. This nasty disease, which causes severe muscle and nerve pain; fatigue; hair loss; and swelling of the joints, connective tissues, and organs, was likely caused by a contaminated batch of supplements produced by a single Japanese manufacturer (the majority of illness cases were traced to that manufacturer). Tryptophan supplements are again available on the market, though some people still have concerns that an overdose may cause illness.
Tryptophan can also trigger side effects such as stomach pain or nausea, diarrhea, gas, appetite loss, headache, dry mouth, blurred vision, weakness, drowsiness, light-headedness, and sexual problems. Those who are pregnant, breastfeeding, or suffer from certain diseases or conditions should not take tryptophan supplements. Tryptophan also interacts with many different medications. If you are considering supplementation, check with a doctor beforehand to be on the safe side.
What Foods Are High in Tryptophan?
It’s always best to get nutrients from natural whole foods whenever possible. Tryptophan is found in protein-rich foods. Good sources include animal products such as eggs, poultry, fish, cheese, and milk, as well as plant products such as soy/tofu, peanuts, pumpkin seeds, sesame seeds, nuts, and certain vegetables including spinach and asparagus.
Other Natural Anxiety Remedies
This article is provided for informational purposes only and is not intended as a substitute for medical or psychiatric advice. Medical concerns should be referred to a qualified doctor.
- Hudson, C., MD, FRCP; Hudson, S., MSW; & MacKenzie, J., RN. (2007). “Protein Source Tryptophan as an Efficacious Treatment for Social Anxiety Disorder: A Pilot Study.” Canadian Journal of Physiology & Pharmacology, 85(9), 928-932.
- Robinson, O.J.; Overstreet, C.; Allen, P.S.; Pine, D.S.; & Grillon, C. (2012). “Acute Tryptophan Depletion Increases Translational Indices of Anxiety But Not Fear: Serotonergic Modulation of the Bed Nucleus of the Stria Terminalis?” Neuropsychopharmacology (In Press).
- Saeed, S.A.; Bloch, R.M.; & Antonacci, D.J. (2007). “Herbal and Dietary Supplements for Treatment of Anxiety Disorders.” American Family Physician, 76(4), 549-556.
- Schruers, K.; van Diest, R.; Overbeek, T.; & Griez, E. (2002). “AcuteL-5-Hydroxytryptophan Administration Inhibits Carbon Dioxide-Induced Panic In Panic Disorder Patients.” Psychiatry Research, 113(3), 237-43.
- The George Mateljan Foundation. (2012). “Tryptophan.” The World’s Healthiest Foods, WHFoods.com.
- University of Maryland Medical Center. (2010). “Tryptophan – Overview.” UMM.edu.
- WebMD. (2015). “L-Tryptophan.”WebMD.com.