Amino acids

L-Theanine — timing, dose & interactions

Amino acid from tea leaves that promotes relaxed alertness; small human trials suggest benefits for stress and sleep quality.

Timing

When to take it

Bedtime for sleep quality, or in the morning with coffee to smooth out caffeine.

Interactions

L-Theanine with other supplements

Safety

Medications & health conditions

NoteSedatives or sleep medication

L-theanine may add a mild calming effect. Usually mild, but be cautious when first combining with sleep medication.

Mechanism-based

Buying guide

What to look for on the label

  • L-Theanine

    • Suntheanine® (pure L-isomer)

FAQ

Common questions

When is the best time to take L-Theanine?

Bedtime. Bedtime for sleep quality, or in the morning with coffee to smooth out caffeine.

Should L-Theanine be taken with food?

It can be taken with or without food. Bedtime for sleep quality, or in the morning with coffee to smooth out caffeine.

Can you take L-Theanine with Ashwagandha?

Yes — just be aware the calming effects may add up, especially at night. Start one at a time. Avoid combining with alcohol or sleep medications without advice.

Can you take L-Theanine with Caffeine?

Yes — it's one of the best-studied supplement pairings. Take them together in the morning. Avoid caffeine after early afternoon.

Sources

References

  1. 01Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials. Nutr Neurosci 2026.