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L-Theanine 250 mg

product on market Capsule Kirkman 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

L-theanine is supported by moderate evidence for its ability to promote relaxation and reduce stress without causing sedation. Research indicates it may improve attention and cognitive function when used alone or with caffeine. This ingredient is generally recognized as safe for most adults.

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

Label

Product Label

Label for L-Theanine 250 mg
Open Full PDF View on NIH DSLD →
Details

Label Data

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

Supplement Facts — Evidence Check

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

Other Ingredients

Microcrystalline Cellulose Hypromellose Water Magnesium Stearate
Claims

Label Claims — Verification

Unverified All Other
Info

Product Information

Directions for Use

Suggested Use: Take one to two capsules daily or as directed by a physician.

Warnings & Precautions

Keep out of the reach of children.

Formulation Notes

Free of: Milk, Eggs, Fish, Shellfish, Tree Nuts, Peanuts, Wheat or Soy

Hypoallergenic

Gluten-Free

Additional Information

Important: Store in a cool dry place and tightly capped.

Ultra Tested cGMP Certified

503.694.1600

Metadata

Product Details

UPC / SKU8 12325 02214 4
DSLD Entry Date2023-09-25
Product TypeNon-Nutrient/Non-Botanical
FormCapsule
BrandKirkman
DSLD ID297055
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
View all evidence for L Theanine →
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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.