Tryptophan
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Evidence Summary
L-Tryptophan is an essential amino acid and a precursor to serotonin, primarily studied for its role in regulating sleep, mood, and the kynurenine pathway. Research indicates potential benefits for sleep quality and mood regulation, though evidence regarding its efficacy as a standalone treatment for depression is mixed.
Evidence by Condition
Supplementation, particularly when combined with ingredients like mulberry leaf extract, has shown potential to improve sleep quality and sleep initiation.
Meta-analyses have investigated tryptophan and 5-HTP as natural alternatives to traditional antidepressants, but results are varied.
Research explores associations between tryptophan levels and postpartum mood disorders, as well as the effects of acute tryptophan depletion on mood.
Tryptophan metabolism is closely linked to the gut microbiome and the kynurenine pathway, influenced by prebiotics and probiotics.
Effective Doses
Dose ranges are not explicitly stated in the provided research studies.
Key Findings
- L-tryptophan supplementation has been assessed for its positive effect on sleep quality (PMID: 33942088).
- Tryptophan and 5-hydroxytryptophan have been studied as natural alternatives for treating unipolar depression and dysthymia (PMID: 11687048).
- A combination of mulberry leaf extract and tryptophan can improve sleep and post-wake mood in adults (PMID: 40072601).
- There is a documented association between tryptophan levels and postpartum mood disorders (PMID: 35941560).
Limitations
Much of the existing research relies on acute tryptophan depletion models rather than long-term supplementation, and there is a lack of standardized dosing data across clinical trials.
Safety & Interactions
Changes in tryptophan metabolism affect the kynurenine pathway, which can impact the immune system and overall human physiology (PMID: 34114978).
AI-generated summary from 29 peer-reviewed studies. Not medical advice. Always consult a healthcare provider.
Claims vs. Evidence
| Claim Type | % of Products | Evidence Required | Status |
|---|---|---|---|
| All Other | 100% | Tier D (Unclassified) | ✅ Supported |
| Structure/Function | 90% | Tier C (DSHEA Structure/Function (no pre-approval)) | ✅ Supported |
| Nutrient | 61% | Tier D (Unknown) | ✅ Supported |
Research by Topic
Research Evidence (29)
**Purton et al., 2021** | Neurosci Biobehav Rev | Meta Analysis Purton Terry, Staskova Lada, ... Marx Wolfgang. Prebiotic and probiotic supplementation and the tryptophan-kynurenine pathway: A systematic review and meta analysis. Neurosci Biobehav Re...
BACKGROUND: 5 Hydroxytryptophan (5-HTP) and tryptophan are so-called natural alternatives to traditional antidepressants, used to treat unipolar depression and dysthymia. OBJECTIVES: To determine whether 5-HTP and tryptophan are more effective than p...
BACKGROUND: 5 Hydroxytryptophan (5-HTP) and tryptophan are so-called natural alternatives to traditional antidepressants, used to treat unipolar depression and dysthymia. OBJECTIVES: To determine whether 5-HTP and tryptophan are more effective than p...
CONTEXT: L-tryptophan (Trp) has been documented to aid sleep, but a systematic compilation of its effect on sleep quality is still limited. OBJECTIVE: We assessed the effect of Trp supplementation on sleep quality via meta-analysis and meta-regressio...
BACKGROUND: Previous studies have suggested that individuals recovered from anorexia nervosa (AN) are characterized by increased serotonergic (5-HT) activity that might be related to elevated levels of anxiety. Assuming these traits to be also presen...
Over 50% of women experience mood disturbance in the postpartum period, with significant implications for maternal and infant health but identifying those at risk is not easily possible. The essential amino acid, tryptophan (TRP) through its neuroact...
L-tryptophan (TRP), one of the essential amino acids in humans, is a precursor of serotonin, and hence its intake is closely related to the suppression of depressed and anxious moods. We did a systematic review of RCTs to examine the effects of trypt...
OBJECTIVES: Fibromyalgia syndrome (FMS) is a chronic clinical condition characterized by pain, fatigue, altered sleep, and cognitive disturbances. The purpose of this study was to compare two alternative treatments (nutraceutical and acupuncture) in ...
BACKGROUND: The usage of probiotics has expanded beyond the areas of gut and immune health improvement. Several studies have shown the positive impact associated between probiotics and stress, cognition, and mood; a relationship referred to as the gu...
**Shaw et al., 2002** | Aust N Z J Psychiatry | Meta Analysis Shaw Kelly, Turner Jane, Del Mar Christopher. Are tryptophan and 5-hydroxytryptophan effective treatments for depression? A meta-analysis. Aust N Z J Psychiatry. 2002-Aug;36(4):488-91 OBJE...
Acute tryptophan depletion (ATD) induces depressive symptoms in 50-60% of selective serotonin reuptake inhibitor (SSRI) treated, recovered depressed patients. However, no reliable predictors of mood response to ATD have been established. In the prese...
PURPOSE: Validated biomarkers of food intake (BFIs) have recently been suggested as a useful tool to assess adherence to dietary guidelines or compliance in human dietary interventions. Although many new candidate biomarkers have emerged in the last ...
Changes in tryptophan metabolism affect human physiology including the immune system, mood, and sleep and are associated with human immunodeficiency virus (HIV) pathogenesis. This study investigates whether the treatment of HIV-infected individuals w...
OBJECTIVES: Temporomandibular disorders (TMDs) are usually treated with occlusal appliances and supportive treatments such as physical therapy and drugs. Supplements can be included among potential supportive therapies, with the aim of reducing the u...
PURPOSE: In the current study we evaluated a blend of ingredients containing mulberry leaf extract (to lower postprandial glucose of the evening meal), tryptophan (facilitator of the sleep initiation) to benefit sleep initiation and quality in adults...
INTRODUCTION: Melatonin plays a key role in sleep regulation. Combining melatonin with its precursors, L-tryptophan (LT) and 5-Hydroxytryptophan (5HTP), may influence sleep-related outcomes, but evidence in children with neurodevelopmental disorders ...
BACKGROUND: Headache is one of the main complaints in pediatric neurology. Exogenous melatonin has been shown to be useful and safe in improving sleep-wake cycles and sleep quality in children. Tryptophan as well plays a key role in sleep regulation....
Anxiety, mood disturbance, eating and sleep disorders, and dissatisfaction with body image are prevalent disorders in women with fibromyalgia. The authors of this study aimed to determine the effects of tryptophan (TRY) and magnesium-enriched (MG) Me...
We tested the hypothesis that presleep consumption of α-lactalbumin (LA), a fraction of whey with a high abundance of tryptophan, would improve indices of sleep quality and time-trial (TT) performance in cyclists relative to an isonitrogenous collage...
OBJECTIVES: To investigate the effect of evening whey protein supplementation, rich in tryptophan, on sleep in elite male Australian Rules Football players. DESIGN: Double-blinded, counterbalanced, randomized, cross-over study. METHODS: Sleep was ass...
OBJECTIVES: The aim of the study was to evaluate the effects on infant growth and tolerance of a Test infant formula based on a novel whey extraction and demineralization process, compared to a Standard formula and a breastfed reference arm. METHODS:...
Evening consumption of a whey protein rich in the amino acid tryptophan, alpha-lactalbumin (ALAC), has previously shown to benefit sleep-particularly among poor sleepers. Given trained populations often experience sleep difficulty, this study investi...
Athletes often experience poor sleep quality and quantity which may hinder physical performance and cognitive function. Presleep nutritional strategies may be an alternative to pharmacological interventions to improve sleep. The aim of this study was...
Fibromyalgia (FM) is a prevalent and multifactorial condition requiring pharmacological and non-pharmacological interventions for its management. Coenzyme Q10 (CoQ10), magnesium, and tryptophan are associated with FM symptoms, but their combined effe...
We aimed to study the potential impact of daily consumption of walnuts on urinary 6-sulphatoxymelatonin (6-SMT) levels and sleep quality parameters. We conducted an open-label randomized crossover trial (NCT04799821) in 76 young adults (24.1 ± 3.4 ye...
Chronic stress-induced sleep disorders are characterized by disrupted sleep architecture and a significant reduction in slow-wave sleep (SWS). These disorders represent a major public health challenge and are mechanistically linked to the hyperactiva...
BACKGROUNDGut microbes and their metabolites contribute to the host circulating metabolome and exhibit diurnal variation influenced by sleep-wake cycles and meal timing. Sleep deprivation alters the rhythmic circulating metabolome, but its impact on ...
**NCT ID**: NCT02367482 **Phase**: **Status**: COMPLETED **Enrollment**: 20 **Completion**: 2023-12-31
**NCT ID**: NCT02462746 **Phase**: PHASE1 **Status**: COMPLETED **Enrollment**: 24 **Completion**: 2016-04
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Frequently Asked Questions
What is L-Tryptophan and how does it work?
L-Tryptophan is an essential amino acid that the body uses as a precursor to produce serotonin. It plays a key role in regulating sleep, mood, and the kynurenine pathway in the body.
Can L-Tryptophan help improve my sleep?
There is moderate evidence suggesting that L-Tryptophan can improve sleep quality and help you fall asleep more easily. Some research even indicates that combining it with mulberry leaf extract may improve both sleep and your mood after waking up.
Is L-Tryptophan effective for treating depression?
There is moderate evidence investigating L-Tryptophan as a natural alternative to traditional antidepressants, but the results are mixed. Because the evidence is varied, it should not be relied upon as a standalone treatment for depression.
Does L-Tryptophan help with anxiety or postpartum mood?
There is currently weak evidence regarding the use of L-Tryptophan for anxiety and mood regulation. While some studies have noted an association between tryptophan levels and postpartum mood disorders, more research is needed.
What is the recommended dose of L-Tryptophan?
The provided research does not explicitly state a specific effective dose range for supplementation. You should consult with a healthcare professional to determine an appropriate dose for your needs.
Are there any safety concerns or side effects with L-Tryptophan?
Changes in how your body processes tryptophan can affect the kynurenine pathway, which may impact your immune system and overall physiology. It is important to be aware of how supplementation might influence these biological processes.
Are there any drug interactions or people who should avoid L-Tryptophan?
No specific drug interactions have been documented for L-Tryptophan in the available research. However, because it can affect the immune system and metabolic pathways, you should consult a doctor before use, especially if you have underlying health conditions.
Answers generated from research evidence. Not medical advice.