L-Theanine

product on market Capsule SuperiorLabs 🟢 Safety: 100/100
Brand: SuperiorLabs
🟢 100/100

This product looks safe

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

Product Label

Label for L-Theanine
📄 Open Full PDF View on NIH DSLD →
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Label Data

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

Supplement Facts — Evidence Check

250 mg
📊 Market median: 200.0mg (358 products) 📚 9 studies (Tier A: 0, B: 2)
This product: 250mg

Other Ingredients

natural Rice concentrate Plant Cellulose

Label Claims — Verification

❓ All Other
❓ Structure/Function
All Other (99% of products) Structure/Function (92% of products) Nutrient (22% of products)

Target Groups

Adult (18 - 50 Years)

Product Information

📋 Directions for Use

Suggested Use: As a dietary supplement, adults take 1 capsule one to two times daily, or as directed by your health care practitioner. Best when taken with a meal.

⚠️ Warnings & Precautions

Caution: Do not exceed recommended dosage.

Please consult physician before consuming this product if pregnant or nursing, taking medication or have a medical condition.

Not intended for use by individuals under the age of 18.

Do not use if safety seal is damaged or missing.

Keep out of reach of children.

🧪 Formulation Notes

L-Theanine is an analog of the amino acids L-Glutamine and L-glutamic acid. L-Theanine supports relaxation, and maintains mental clarity.

L-Theanine capsules manufactured by Superior Labs contain 250mg pure L-Theanine with absolutely no magnesium stearate, dioxides, preservatives or other potentially harmful artificial ingredients of any kind.

L-Theanine capsules manufactured by Superior Labs contain 250mg pure L-Theanine with absolutely no magnesium stearate, dioxides, preservatives or other potentially harmful artificial ingredients of any kind.

This product is formulated, developed and manufactured in an FDA registered and GMP compliant facility, 3rd party inspected by a leading compliance authority for quality assurance.

100% Natural Pure and potent Amino acid

Induce relaxation Support brain function Support cardiovascular function Relieve mental and physical stress

Does Not Contain: Magnesium stearate, dioxides, preservatives, or artificial ingredients of any kind.

Additional Information

Store in a cool, dry place.

Metal Safe Heavy Metal Tested Made in USA Certified GMP Facility

Product Details

UPC / SKU 8 50569 00619 3
DSLD Entry Date 2020-06-24
Product Type Non-Nutrient/Non-Botanical
Form Capsule
Brand SuperiorLabs
DSLD ID 227910
Data Updated 2026-04-11

Research Evidence

37 Research Sources
53 Avg Quality Score
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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