هذه الصفحة باللغة الإنجليزية
Ingredient guide
L-theanine: evidence, dose and safety
L-theanine is an amino acid found almost only in tea leaves.
At a glance
- Strongest evidence
- C Limited
- Dose in our plans
- 200 mg a day for adults
- Adult upper limit
- 400 mg a day from food and supplements together
- Safety checks
- 0 situations and 0 medicine or supplement interactions, checked against your answers in every plan
- Reviewed
- Atrum Labs clinical team (MD, PhD), November 2026
What the research looked at
Each line is one body of research, graded A (strong) to D (weak). How we grade evidence. What each study measured is explained in your personal plan.
| Grade | Who was studied | References |
|---|---|---|
| C | Healthy adults |
|
How much
- Our plans usually use 200 mg a day for adults. The exact dose depends on your lab results, age and medicines.
- Adult upper limit: 400 mg a day from food and supplements together. Source: Trials used 200-400 mg a day (Hidese S et al. Nutrients 2019).
- Children's doses are set by age, and some ingredients are for adults only.
Products with L-theanine
Written and reviewed by the Atrum Labs clinical team (physician-scientists, MD, PhD) from our clinical knowledge base, version 0.2.0-draft. This page is general information, not medical advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle.
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