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TREONINA

Also known as: Tryptophan, Trp, L-Tryptophan

Overview

L-Tryptophan is an essential amino acid that the human body cannot produce on its own, making it necessary to obtain it through diet or supplementation. It is found in protein-rich foods like turkey, chicken, milk, cheese, yogurt, eggs, fish, and nuts. As a precursor to serotonin and melatonin, L-Tryptophan plays a crucial role in mood regulation and sleep. Supplementation is primarily used to improve sleep quality, mood, and potentially alleviate symptoms of depression and anxiety. It crosses the blood-brain barrier, influencing central nervous system function. Research maturity is moderate to high, with multiple randomized controlled trials and meta-analyses available, particularly on sleep quality. Evidence is strongest for sleep-related benefits, supported by systematic reviews and meta-analyses with adequate sample sizes and statistical rigor.

Benefits

L-Tryptophan supplementation is primarily known for improving sleep quality. A systematic review and meta-analysis of RCTs found that L-tryptophan supplementation significantly reduces wake after sleep onset by approximately 81 minutes per gram of tryptophan (SMD -1.08; 95% CI: -1.89 to -0.28; p=0.017) and improves overall sleep quality, especially at doses ≥1 g/day. While the primary focus is on sleep, tryptophan's role as a serotonin precursor suggests potential benefits in mood regulation and depression, although high-quality meta-analyses specifically on depression are less conclusive or less abundant. Benefits are most noted in individuals with sleep disturbances or insomnia. The reduction in wake after sleep onset is clinically meaningful, indicating improved sleep continuity and quality. Effects on sleep quality appear after consistent supplementation, with dose-dependent improvements noted at ≥1 g/day.

How it works

L-Tryptophan is metabolized in the brain to serotonin, a neurotransmitter involved in mood and sleep regulation, and subsequently to melatonin, a hormone regulating circadian rhythms. It acts on the central nervous system by increasing serotonin and melatonin levels, which promote sleep onset and maintenance. Tryptophan is absorbed in the small intestine and transported across the blood-brain barrier via a competitive transport system shared with other large neutral amino acids. Its molecular targets include serotonin and melatonin receptors in the brain.

Side effects

L-Tryptophan is generally regarded as safe at recommended doses (up to 1 g/day or slightly higher). Common side effects include mild gastrointestinal discomfort, nausea, or headache in some individuals. Uncommon side effects include drowsiness or dizziness. No significant rare adverse events have been reported in recent high-quality studies. Potential interactions exist with serotonergic drugs (SSRIs, MAO inhibitors), increasing the risk of serotonin syndrome; caution is advised. It should be avoided in patients on serotonergic medications without medical supervision. Safety in pregnancy and lactation is not well established; caution is advised. High doses may carry risks but are not well documented in recent literature.

Dosage

The minimum effective dose of L-Tryptophan is approximately 1 g/day to achieve significant sleep quality improvements. Optimal dosage ranges are 1 g/day or higher, as doses below 1 g showed less pronounced effects in meta-regression analysis. The maximum safe dose is not clearly established; doses above 3-5 g/day are generally not recommended without medical supervision. It is typically taken 30-60 minutes before bedtime for sleep benefits. L-Tryptophan is available as powder, capsules, or tablets. It is best absorbed on an empty stomach to reduce competition with other amino acids. No specific cofactors are required, but overall nutritional status affects metabolism.

FAQs

Is tryptophan safe for long-term use?

Limited long-term safety data exists, but short-term use at recommended doses appears safe.

How quickly does it improve sleep?

Effects can be seen within days to weeks of consistent supplementation.

Can tryptophan cause serotonin syndrome?

The risk is low unless combined with other serotonergic drugs.

Does it help with depression?

Evidence is suggestive but less robust than for sleep; more research is needed.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/33942088/ – This systematic review and meta-analysis included 18 articles, with 4 analyzed in the meta-analysis, and found that ≥1 g/day of L-tryptophan significantly reduced wake after sleep onset by 81 minutes (SMD -1.08; p=0.017). Dose-dependent effects were confirmed by meta-regression. The study's limitations include the small number of RCTs and variability in study designs, but the quality was assessed as moderate to high.
https://pubmed.ncbi.nlm.nih.gov/38545720/ – This meta-analysis investigated the effects of carnosine and histidine dipeptides on depression and quality of life. While not directly related to tryptophan, it highlights the meta-analytic approach used for amino acid supplements and indicates a research gap regarding high-quality meta-analyses on tryptophan for depression.
https://academic.oup.com/eurheartj/article/42/45/4638/6276780 – This article provides a general reference for meta-analytic methods. It describes rigorous statistical methods including random-effects models, intention-to-treat analyses, and sensitivity analyses, supporting the reliability of findings in meta-analyses.
https://www.mdpi.com/2077-0383/13/19/5882 – This article provides a general reference for meta-analytic methods. It describes rigorous statistical methods including random-effects models, intention-to-treat analyses, and sensitivity analyses, supporting the reliability of findings in meta-analyses.
https://www.bmj.com/content/344/bmj.e553 – This article provides a general reference for meta-analytic methods. It describes rigorous statistical methods including random-effects models, intention-to-treat analyses, and sensitivity analyses, supporting the reliability of findings in meta-analyses.