Unraveling The Mysteries of Tryptophan

Unraveling The Mysteries of Tryptophan.

As Thanksgiving approaches, the anticipation of a hearty feast surrounded by loved ones takes center stage. A nutrient often in the spotlight during this holiday is tryptophan, a naturally occurring amino acid found in turkey and other protein-rich foods. While tryptophan is commonly associated with the drowsiness that many experience post-Thanksgiving meal, its effects go far beyond a turkey-day sleep aid. In this article, we'll explore the wonders of tryptophan, delving into its role in sleep, mood regulation, and its potential benefits for a wide array of health conditions.


Why do we need Tryptophan?

Tryptophan is one of eight essential amino acids that our bodies cannot produce endogenously, so it must be obtained through diet or supplementation. It exists in two forms or isomers in nature, L-Tryptophan and D-Tryptophan, differing only by the orientation of their molecules in space. The L-Tryptophan isomer is the preferred, most effective form utilized by our bodies to help synthesize proteins and maintain function of muscles, enzymes, and neurotransmitters. Rich dietary sources of tryptophan include foods like turkey, poultry, eggs, and dairy products including milk, yogurt, and cheese. Z-Night, Dr. Zelenko’s specially formulated sleep remedy, is an example of a supplemental version of tryptophan. Once ingested tryptophan serves several critical roles in the body including acting as a precursor to serotonin, a neurotransmitter or chemical messenger in the brain, known for its role in mood regulation and sleep.1


Common Tryptophan Sources2:

Poultry – Turkey and Chicken

Fish – Salmon, Tuna, Cod, and Tilapia

Other Meats – Beef, Lamb, and Pork

Dairy – Milk, Yogurt, Cheese


Nuts & Seeds – Almonds, Peanuts, Sunflower seeds and Pumpkin seeds

Fruit – Apples, Bananas, and Dried Prunes

Legumes – Lentils, Chickpeas, and Beans

Whole Grains – Brown rice, Quinoa, and Oats

Soy Products – Tofu and Soy milk


Sleep Support – Tryptophan and the Thanksgiving Nap

Many Americans are familiar with the ‘post-Thanksgiving meal nap’ phenomenon. Not long after your turkey centered meal concludes, drowsiness sets in accompanied by an overwhelming desire to lay down for a nap. This phenomenon can be attributed to the increased intake of turkey and its associated tryptophan. Tryptophan is a precursor to serotonin, which is a precursor to melatonin—the hormone responsible for regulating sleep-wake cycles. In fact, evidence suggests that adequate levels of tryptophan, and thus serotonin and melatonin, may contribute to improved sleep quality and duration, while reducing symptoms of other disruptive disorders like anxiety and depression.3,4

Taking Dr. Zelenko’s Z-Night formulation before bed is a simple, safe, and effective way to boost tryptophan levels and induce and improve sleep to boost health and well-being overall.


Mood and Stress Regulation – An Effective Therapy for Anxiety and Depression

Beyond its role in improving sleep quality and duration, tryptophan plays a crucial role in regulating mood. Serotonin, often referred to as the ‘feel-good’ neurotransmitter, is created using tryptophan in our bodies. This is important for emotional well-being because with adequate levels of serotonin, our moods improve, reactions to stress are palliated, and risks of developing depression are reduced.5 Accordingly, tryptophan has been used since the 1970s as an effective adjunctive therapy for people dealing with depression and anxiety.6,7 In fact, one fascinating study found that adults who ate tryptophan-enriched cereal daily experienced improvements in overall sleep quality and significant reductions in anxiety and depression symptoms.8


Additional Health Correlations and Potential Therapeutic Uses

Beyond its well-known use in improving sleep, mood, and stress management, tryptophan has been explored for its potential therapeutic uses in a variety of health conditions including autism, IBS, multiple sclerosis, cognitive function, kidney disease, and microbial infections.9 Below is a short list of some other examples of potential therapeutic uses for tryptophan.


Cardiovascular Disease – Research shows an inverse relationship between tryptophan levels and cardiovascular disease indicating that tryptophan may serve a protective role in the cardiovascular system.10

Fibromyalgia – Some studies suggest that tryptophan supplementation may help alleviate symptoms of fibromyalgia, a chronic condition characterized by widespread pain and tenderness.

Chronic Fatigue Syndrome (CFS) – Research indicates that CFS may be linked to abnormalities in tryptophan associated protein synthesis pathways which may be alleviated with proper supplementation.10

Pain Management – Evidence suggests that chronic pain disorders may be linked to altered tryptophan metabolism, and proper levels may be linked to a strengthened pain tolerance. It has also been investigated for its role in managing condition like migraines and tension headaches.11,12

Premenstrual Syndrome (PMS) – Appropriated levels of serotonin, influenced by tryptophan, is thought to play a role in alleviating symptoms of PMS, such as irritability, tension, and mood swings.13


Tryptophan – Far More Than a Thanksgiving Sleep Aid

As we gather to celebrate Thanksgiving and indulge in a delicious meal, let's appreciate the many roles of tryptophan beyond helping to induce a nap post-meal. From promoting better sleep to supporting mood regulation and addressing a variety of health conditions, tryptophan showcases its versatility as a nutrient with far-reaching benefits. While more research is still needed to fully understand its full potential, incorporating tryptophan-rich foods into our diets, or supplementing as needed may contribute to overall well-being and health.

Medical Disclaimer: The content in this article should not be taken as medical advice or used as a direct recommendation for any treatment or medication. Always consult with a properly licensed healthcare provider before making any changes to your current health and wellness routine.



        1.    Acheson, A., & et al. (2009, March 23). L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. International Journal of Tryptophan Research, 2: 45-60. Retrieved from: https://doi.org/10.4137%2Fijtr.s2129

 2.    Bridges, M. (2022, May 27). Tryptophan. MedlinePlus. Retrieved from: https://medlineplus.gov/ency/article/002332.htm

 3.    Chodakowska, I. M., Sejbuk, M., & Witkowska, A. M. (2022, May 2). Sleep Quality: A Narrative Review on Nutrition, Stimulants, and Physical Activity as Important Factors. Nutrients, 14(9): 1912. Retrieved from: https://doi.org/10.3390%2Fnu14091912  (x)

4.    Harris, L., Sanjiv, A., & Victor, F. (2016, December). Tryptophan Intake in the US Adult Population Is Not Related to Liver or Kidney Function but Is Associated with Depression and Sleep Outcomes. The Journal of Nutrition, 156(12): 2609-2615. Retrieved from: https://doi.org/10.3945/jn.115.226969  (y)

 5.    Bai, W., & et al. (2022, July). Tryptophan-rich diet ameliorates chronic unpredictable mild stress induced depression- and anxiety-like behavior in mice: The potential involvement of gut-brain axis. Food Research International, 157. Retrieved from: https://doi.org/10.1016/j.foodres.2022.111289

 6.    Iwahori, Y., Kikuchi, A. M., & Tanabe, A. (2021). A systematic review of the effect of L-tryptophan supplementation on mood and emotional functioning. Journal of Dietary Supplements, 18(3): 316 – 333. Retrieved from: https://doi.org/10.1080/19390211.2020.1746725

 7.    Tryptophan. (n.d.). Mental Health America. Retrieved from: https://www.mhanational.org/tryptophan.

 8.    Barriga, C., & et al. (2013, August). Tryptophan-enriched cereal intake improves nocturnal sleep, melatonin, serotonin, and total antioxidant capacity levels and mood in elderly humans. AGE, 35: 1277-1285. Retrieved from: https://doi.org/10.1007/s11357-012-9419-5.

 9.    Friedman, M. (2018, September 26). Analysis, Nutrition, and Health Benefits of Tryptophan. International Journal of Tryptophan Research, 11. Retrieved from: https://doi.org/10.1177%2F1178646918802282

 10.  Boekholdt, S. M., & et al. (2023, October 20). Tryptophan metabolites and incident cardiovascular disease: The EPIC-Norfolk prospective population study. Atherosclerosis,. Retrieved from: https://doi.org/10.1016/j.atherosclerosis.2023.117344

 11.  Ackenheil, M., & et al. (2002, December). Evidence for an Altered Tryptophan Metabolism in Fibromyalgia. Neurobiology of Disease, 11(3): 434-442. Retrieved from: https://doi.org/10.1006/nbdi.2002.0563

 12.  Anderson, G., Berk, M., & Maes, M. (2014, February). Biological phenotypes underpin the physio-somatic symptoms of somatization, depression, and chronic fatigue syndrome. Acta Psychiatrica Scandinavica, 129(2): 83-97. Retrieved from: https://doi.org/10.1111/acps.12182

 13.  Kortesi, T., Spekker, E., & Vecsei, L. (2022, December 5). Exploring the Tryptophan Metabolic Pathways in Migraine-Related Mechanisms. Cells, 11(23): 3793. Retrieved from: https://doi.org/10.3390/cells11233795

 14.  Annable, L., Liyanage, N., Steinberg, S., & Young, S. N. (1999, February 1). A placebo-controlled clinical trial of L-tryptophan in premenstrual dysphoria. Biological Psychiatry, 45(3): 313 – 320. Retrieved from: https://doi.org/10.1016/s0006-3223(98)00005-5


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