L-Theanine Dosage Chart
L-theanine is an amino acid found naturally in green tea that promotes calm alertness without drowsiness. It increases alpha brain wave activity and modulates neurotransmitters (GABA, glutamate). Its synergy with caffeine is well-documented — the combination enhances focus while reducing caffeine-associated jitteriness.
L-Theanine Dosage by Age Group
| Age Group | Age Range | Dose Range | Notes |
|---|---|---|---|
| Adults — calm focus (with caffeine) | 18–64 years | 100–200 mg | 2:1 ratio with caffeine (100 mg caffeine : 200 mg L-theanine) |
| Adults — anxiety reduction | 18–64 years | 200–400 mg | Standalone dose; no caffeine needed |
| Adults — sleep support | 18–64 years | 200–400 mg | Take 30–60 min before bed |
| Adults — high stress | 18–64 years | 400–600 mg | 600 mg studied in some anxiety trials |
When and how to take L-Theanine
For cognitive enhancement with caffeine, take together before a task requiring focus. For anxiety or sleep, take 30–60 minutes before the desired effect. Effects are felt within 30–60 minutes of oral dosing.
Available Forms
Most convenient. Suntheanine (branded form) has good quality control.
Common dosages: 100, 200, 400 mg per capsule
Flexible dosing; mixes into beverages.
200 mg is approximately 1/16 tsp
Naturally contains 5–50 mg per cup. Low relative to supplement doses.
Matcha green tea has higher L-theanine content (25–46 mg/cup)
Safety Cautions
- Very high doses (600+ mg) may cause drowsiness or mild sedation.
- Generally well-tolerated with few reported side effects at studied doses (100–400 mg).
- May potentiate blood pressure-lowering medications.
- Avoid driving or operating machinery when first trying high doses (400+ mg) until you know your response.
- Limited data on long-term use above 400 mg/day.
Frequently Asked Questions
What is the best L-theanine dosage for focus?
For focus, combine 100–200 mg L-theanine with 50–100 mg caffeine. The classic ratio studied is 2:1 (L-theanine: caffeine). This combination enhances attention, reduces mind-wandering, and blunts the jitteriness from caffeine. L-theanine 200 mg alone (without caffeine) promotes relaxed alertness.
How much L-theanine is 600 mg?
L-theanine 600 mg is the highest dose used in clinical anxiety studies. It is three times the standard 200 mg dose and six times the amount in a strong cup of green tea. At 600 mg, mild sedation may occur. Start at 200 mg and increase only if needed for anxiety reduction.
Can I take L-theanine every day?
Yes. L-theanine has a favorable safety profile for daily use. It is present in green tea consumed daily by millions worldwide. Supplement doses of 200–400 mg daily have been studied for weeks to months without adverse effects. Tolerance does not appear to develop.
Sources & References
- Nobre AC et al., Asia Pac J Clin Nutr 2008 — L-theanine and cognitive performance
- Kimura K et al., Biol Psychol 2007 — L-theanine reduces mental stress
- EFSA scientific opinion on L-theanine and cognitive function