L-Theanine
Full ranking Dose tool Products (764)
Key facts
Daily Value (US FDA)—
Tolerable Upper Intake Level (UL)— Reference upper value (cited, not a UL): 250 mg
Median (Per day)150 mgP5 25 – P95 300
Products764
Sources: https://webprod.hc-sc.gc.ca/nhpid-bdipsn/atReq?atid=l.theanine2&lang=eng · Health Canada NNHPD monograph: 200-250 mg L-theanine/day
Daily dose across products (mg/day)
Reference upper value (cited, not a UL) 250
15 mglog scale · n=7641,000 mg
Label data from official national databases and brand websites, as declared; not lab-verified.
Common questions
Is there an official upper limit for L-Theanine?
No UL has been set. We use a cited reference upper value of 250 mg per day. It comes from the linked study or assessment and is not a regulatory limit. [source]
How much L-Theanine do products usually contain per day?
As of 2026-11-01, 764 products list a comparable daily dose (780 dose records; one product can have several). The median is 150 mg per day, and 90% of records fall between 25 and 300 mg. Figures come from labels and are not lab-tested. [source]
Top ranked
| Rank | Brand | Product | Per day | Score |
|---|---|---|---|---|
| 1 | Vitamin World | L-Theanine 200 mg | 200 mg | 100.0 |
| 1 | Swanson | Suntheanine L-Theanine 100 mg | 200 mg | 100.0 |
| 3 | The Vitamin Shoppe | L-Theanine 100 mg | 100 mg | 97.8 |
| 3 | The Vitamin Shoppe | L-Theanine 200 mg | 200 mg | 97.8 |
| 5 | Douglas Laboratories | L-Theanine | 100 mg | 94.4 |
For information only; not medical advice. Talk to a doctor or pharmacist before starting or stopping any supplement.