This powder delivers 285 mg of **L-theanine** per serving, an amino acid naturally found in tea leaves that promotes relaxation without making you drowsy. The dose here sits above the typical 100-250 mg clinical range, with 200 mg being the most studied amount for reducing stress and promoting calm focus. At 285 mg you're well within effective territory, and the powder format lets you easily adjust your dose down if you prefer the standard 200 mg.

L-theanine works by increasing alpha brain wave activity, which is the pattern your brain produces during a relaxed but alert state. Clinical evidence is moderate, with studies showing it can lower perceived stress and support sleep quality when taken as part of a calming routine. It does not act as a sedative, so you can take it during the day for focus or in the evening to wind down. One well-studied use case is pairing it with caffeine, where theanine smooths out the jittery edge while preserving the alertness.

The formula is pure L-theanine powder with zero additional ingredients. With 93 servings per container, you're looking at roughly a three-month supply at daily use. Because L-theanine has no meaningful form variations that affect absorption, the standard form used here delivers the same bioavailability as branded versions like Suntheanine.

BioStacks
NOW

L-Theanine

Powder · 0.125 tsp · 93 servings · $0.24/serving

iHerbAmazon

Best for

Stress & MoodSleep

Ingredients (1)

L-Theanine

100%

Dose

285 mg

Target

100–250 mg

Form

—

Other Ingredients (1)

NoneFood

Placeholder for labels whose Other Ingredients line reads 'None' — indicates no additional excipients.

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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.

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