Tryptophan is one of the 8 essential amino acids in the human body, in addition to playing an important role in protein synthesis, it is also an important precursor to the synthesis of serotonin, melatonin, kynurenine, and nicotinic acid, and is often believed to improve depression and sleep-related disorders through additional supplementation. Note 9
Tryptophan is also known as L-tryptophan because the L isomer form is bioavailable to all amino acids and can transcend the blood-brain barrier.
Natural foods rich in tryptophan are oats, bananas, milk, fish, cheese, chicken, peanuts and dark chocolate…
What are the benefits of tryptophan in empirical medicine? Are there any side effects and contraindications? See text analysis for details.
What are the recommended empirical benefits of tryptophan?
1. Tryptophan is beneficial to sleep quality
Sleep is essential for maintaining a healthy immune system, restoring energy, and consolidating memory. About 45 percent of adults do not get the recommended 7 to 9 hours of sleep per night.
Getting good sleep quality, i.e. low sleep latency, waking up less often after falling asleep, good sleep efficiency, and duration is necessary for overall health and well-being.
If it takes more than 30 minutes to fall asleep, more than once at night, or more than 20 minutes to fall asleep after waking up, sleep quality is poor. Even if the recommended amount of sleep is reached, you may feel tired the next day.
A systematic literature review and meta-analysis (including four randomized controlled trials) suggested that tryptophan supplementation helped reduce the total time spent waking up after falling asleep. WASO). Note 1
In addition, tryptophan was most effective in reducing the total time spent waking up after falling asleep with a supplemental dose of ≥ 1 g.
*Conclusion: Tryptophan supplementation may have a positive effect on sleep quality improvement, but more studies are needed to further verify due to the small sample size.
2. Tryptophan is beneficial to depression (major depressive disorder)
Depression is currently the most prevalent mood disorder, affecting about 18% regardless of age, race, and socioeconomic background, and may include low mood, loss of interest in things, sleep disorders, decreased appetite, feeling worthless, unable to concentrate and even have suicidal thoughts.
Many chronic diseases are often causally related to depression, such as diabetes, heart disease, autoimmune diseases and pain, making diagnosis and treatment difficult.
A meta-analysis (24 studies, 1537 participants) noted that blood tryptophan concentrations were significantly lower in patients with depression, with the largest difference among those treated without treatment. Note 4
*Conclusion: Lower blood tryptophan concentration is significantly associated with the onset of depression, but more empirical evidence is needed on whether oral administration can bring benefits.
3. Tryptophan is beneficial for premenstrual dysphoric disorder
About 80% of women have mild premenstrual symptoms during the menstrual cycle, with 3% to 8% of them being severe (irritability, impulsivity, depression, and carbohydrate cravings being the most pronounced), often severely interfering with work, family, and relationships.
*Conclusion: Oral tryptophan may help improve PMIA, and the mechanism behind it is related to increasing serotonin and formation, but more large studies are needed.
4. Tryptophan is beneficial for behavioral regulation
Impulsive aggressive behavior plays an important role in many violent and criminal events, and these behaviors are one of the most important features of borderline personality and antisocial personality disorder. Note 6
Studies have found that the neurotransmitter serotonin has an inhibitory effect in the brain, can regulate emotions and behavior, and inhibit aggressive thoughts, and once the effect is abnormal, it will increase the probability of bad behavior.
A double-blind crossover study (15 days, 39 people with argumentative personality traits) found that taking tryptophan could not only reduce argumentative and dominant behavior, but also increase consent behavior and affinity traits, and had a positive effect on improving social interaction (although some results were more effective in men). Note 7
Another randomized double-blind controlled study (in 23 boys with aggressive personalities) showed that the use of tryptophan reduced impulsive behavior and improved the ability to empathize and distinguish facial emotions compared with the control group. Note 8
*Conclusion: Tryptophan may have the effect of modulating some impulsivity and aggressive behavior, and enhancing benign social interaction, but the current research scale is still too small, and more large studies are needed to verify.
Are there any side effects of tryptophan?
Since 1988, a major case of tryptophan products has broken out in the United States, and consumers have eosinophilia-myalgia syndrome (EMS) after use, causing thousands of victims, the symptoms are mainly fatigue and strong muscle pain, neuralgia, skin changes, hair loss, rash, etc., and later found to be caused by Japanese manufacturers changing the production process without authorization, resulting in raw material contamination, after the product was removed from the shelves. Notification cases also dropped sharply, and there have been no such cases in subsequent clinical trials.
Other reported adverse reactions or side effects include: sweating, heartburn, stomach pain, hiccups and palpitations, nausea, vomiting, diarrhea, loss of appetite, tinnitus, headache, dizziness, drowsiness, dry mouth, blurred vision, muscle weakness, etc.
1. Do not use by pregnant women, nursing mothers, poor liver and kidney function (because the relevant safety is still unknown).
2. Do not use for people with social anxiety disorder, which may cause symptoms to worsen.
3. Do not use with related antipsychotic drugs, such as antidepressants, sedative sleeping pills and other drugs such as anesthetics (Demerol), antitussive drugs (Dextromethorphan), analgesics (Pentazocine, Tramadol), etc. will affect the use of central nervous system drugs, which may cause unknown risks.