For calm focus without the drowsiness, this **L-Theanine** gives you 100mg per capsule — right at the effective minimum for easing stress and steadying attention. This amino acid from tea nudges your brain into a relaxed-but-alert state and dampens stress reactivity, with consistent clinical backing in the 100–200mg range.

Theanine pairs especially well with caffeine — it smooths out the jitters while sharpening focus, a genuinely well-supported combo worth stacking with your morning coffee. The most-studied single dose is 200mg, and the label allows one to four capsules daily, so two capsules puts you on the firmest research footing for stress relief.

BioStacks
Life Extension

L-Theanine 100 mg

1 Capsule · 60 servings · $0.30/serving

iHerbAmazon

Best for

Stress & Mood

Ingredients (1)

L-Theanine

100%

Dose

100 mg

Target

100–250 mg

Form

—

Other Ingredients (4)

Silicon DioxideAnti-caking

Fine silica powder used to prevent clumping

Vegetable StearateLubricant

A plant-derived salt of stearic acid (typically magnesium or calcium) used as a tablet lubricant

Microcrystalline CelluloseBinder

Plant-derived cellulose used as a binder and filler in supplements

Microcrystalline CelluloseBinder

Plant-derived cellulose used as a binder and filler in supplements

Track this supplement in your stack

Get personalized insights, interactions, and coverage recommendations.

Get Started Free

Similar Supplements

Products that cover similar health dimensions based on their ingredients.

L-Theanine

Pure Encapsulations

L-Theanine

🧘 for Stress & Mood

85
L-Theanine

XYMOGEN

L-Theanine

🧘 for Stress & Mood

85
L-Theanine 150 mg Vegetable Capsules

Solgar

L-Theanine 150 mg Vegetable Capsules

🧘 for Stress & Mood

85
L-Theanine

NOW

L-Theanine

🧘 for Stress & Mood

85
L-Theanine

SuperiorLabs

L-Theanine

🧘 for Stress & Mood

85

Sources & Scoring

Nutrient data (RDA, UL, and safety thresholds) sourced from: NIH Office of Dietary Supplements and National Academies Dietary Reference Intakes (DRI).

This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.

The score analyzes what's on the label: ingredient doses vs. clinical ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.

BioStacks

Know exactly what's in your supplements.

Navigate

  • Home
  • App Store
  • Google Play

Resources

  • Contact & Support
  • Pricing
  • Terms of Service
  • Privacy Policy
  • Refund Policy

Explore

  • Health Areas
  • Best Supplements
  • Nutrients
  • All Supplements

Popular Picks

  • Best Magnesium for Sleep
  • Best Collagen for Skin
  • Best Creatine for Muscle
  • Best Vitamin D for Bone Health
  • Best Probiotics for Digestion
  • Best CoQ10 for Heart
© 2026 BioStacks. All rights reserved. Not medical advice.