L-Theanine
Amino AcidsKey Benefits
How It Works
L-Theanine (found in green tea) crosses the blood-brain barrier and increases alpha brain wave activity, promoting relaxed alertness. It modulates GABA, serotonin, and dopamine levels, and inhibits glutamate excitotoxicity. Structurally similar to glutamate.
Dosage & Timing
Recommended Dosage
100-400 mg daily
Best Time to Take
Morning with caffeine for focus, or evening for relaxation
Recommended Form
Suntheanine branded L-Theanine
Side Effects
Extremely safe. No known side effects at normal doses. May cause mild drowsiness in sensitive individuals.
Drug Interactions
Enhances calming effects of sedatives. Synergistic with caffeine (most popular nootropic stack). No significant negative interactions.
What Does The Research Say?
Human studies show significant anxiety reduction, improved attention, and enhanced alpha wave activity. The L-theanine + caffeine stack is the most well-validated nootropic combination in research. 200mg theanine + 100mg caffeine is the gold standard ratio.
Where to Buy
Buy L-Theanine on Amazon
Compare prices and read reviews →
Pair Supplements With Smart Training
RYVVA tracks your workouts, nutrition, and recovery — so your supplements fuel real progress.
Try RYVVA Free →Testosterone Support From Voy
UK-based TRT and hormone optimisation. Clinician-led, delivered to your door. Blood tests, prescriptions, and ongoing monitoring.
Learn More at Voy →Try Space Goods
Nootropic mushroom blends for focus, energy, and calm. Lion\'s Mane, Cordyceps, Ashwagandha in one daily drink.
Shop Space Goods →LA Muscle Supplements
Premium sports nutrition — protein, pre-workout, testosterone boosters, and fat burners. UK-made.
Shop LA Muscle →Healthy Meals Delivered
Chef-prepared, macro-balanced meals delivered to your door. Perfect for hitting your nutrition goals.
Try Simmer Eats →Horace — Men's Skincare
Premium French skincare for men. Natural ingredients, no fuss. Cleansers, moisturisers, and grooming essentials.
Shop Horace →Vitality Health Insurance
Rewards you for being healthy. Gym discounts, Apple Watch deals, and wellness perks with your health cover.
Get a Vitality quote →Huel — Complete Nutrition
Nutritionally complete meals, shakes, and bars. 26 vitamins and minerals in every serving.
Try Huel →This information is for educational purposes only and does not constitute medical advice. Researched by the editorial team at NexoraOS, supplement user since 2018. Always consult a qualified healthcare professional before starting any supplement. Individual results may vary. Amazon links are affiliate links.