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Suntheanine L-Theanine 125 mg

product on market Capsule Natural Factors Stress-Relax Safety: 100/100
100/100

This product looks safe

  • No ingredients exceed tolerable upper intake levels
  • 100% of ingredients have research evidence
A Label Compliance Grade

What the Evidence Says

AI-generated · Qwen 3.6 · grounded in 1 source · methodology

Suntheanine L-Theanine is supported by strong evidence for its ability to promote relaxation and reduce stress. Research indicates it may improve cognitive function and focus without causing sedation. This ingredient is generally recognized as safe for consumption.

AI-generated summary based on research evidence. Not medical advice.

Label

Product Label

Label for Suntheanine L-Theanine 125 mg
Open Full PDF View on NIH DSLD →
Details

Label Data

1 Vegetarian Capsule(s)
Serving Size
30
Servings
Non-Nutrient/Non-Botanical
Product Type
100%
Evidence Coverage
Ingredients

Supplement Facts — Evidence Check

Market median: 200.0mg (358 products) 9 studies (A:0, B:2)

Other Ingredients

Rice powder Vegetarian Capsule Magnesium Stearate Silica
Claims

Label Claims — Verification

Unverified All Other
Unverified Structure/Function
Info

Product Information

Directions for Use

Suggested Usage: 1-2 capsules 1-2 times per day or as directed by a health professional.

Warnings & Precautions

Cautions: As with any supplement, consult your health professional before use if you are pregnant, breastfeeding, or trying to conceive, or if you are taking medication, have a medical condition, or anticipate a surgery.

Keep out of the reach of children.

Sealed for your protection. Do not use if seal is broken.

Formulation Notes

Suntheanine contains pure L-Theanine, a unique amino acid found in green tea that is emerging as the premier natural product that supports mental calmness and relaxation. Suntheanine is produced via proprietary enzymatic process guaranteeing essentially pure L-Theanine for maximum effectiveness.

Contains no artificial colors, preservatives, or sweeteners; no dairy, sugar, wheat, gluten, yeast, soy, corn, egg, fish, shellfish, animal products, salt, tree nuts, or GMOs.

Suitable for vegetarians/vegans.

Additional Information

isura Non-GMO - Mass Spec Documentation - Lab tested

Natural Factors amino acids are the highest quality pharmaceutical grade products available. Manufactured by Natural Factors to ensure safety and potency in accordance with Good Manufacturing Practices (GMP) of the FDA and Health Canada.

For freshness, store in a cool, dry place.

Product of Canada Recyclable container and label.

Purity & potency guaranteed

Mental calmness & relaxation

R5

Metadata

Product Details

UPC / SKU0 68958 04830 7
DSLD Entry Date2017-07-25
Product TypeNon-Nutrient/Non-Botanical
FormCapsule
DSLD ID76495
Data Updated2026-04-11
Research

Research Evidence

37
Research Sources
53
Avg Quality
22
Rct
10
Systematic Review
3
Meta Analysis
1
Clinical Trial
1
Openfda Safety
B Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials
Systematic Review Nutritional neuroscience 2026 PubMed DOI
B The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis
Meta Analysis Sleep medicine reviews 2025 PubMed DOI
B The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness
Rct Nutritional neuroscience 2010 PubMed DOI
B Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial
Rct Nutrients 2019 PubMed DOI
B The Role of Supplements and Over-the-Counter Products to Improve Sleep in Children: A Systematic Review
Systematic Review International journal of molecular sciences 2023 PubMed DOI
B Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Meta Analysis Nutrition reviews 2025 PubMed DOI
B Effect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-Controlled Crossover Trial
Rct Nutrients 2022 PubMed DOI
B Effect of L-theanine on selective attention in a traffic-related reaction task in sleep-deprived young adults: a double-blind placebo-controlled, crossover study
Rct Nutritional neuroscience 2025 PubMed DOI
B The combined effects of L-theanine and caffeine on cognitive performance and mood
Rct Nutritional neuroscience 2008 PubMed DOI
B Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis
Meta Analysis Nutrition reviews 2014 PubMed DOI
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This product page is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before taking any supplement.