L-Theanine
Of 1,997 on-market l-theanine products in the January 2026 DSLD dump, the median declared dose is 100 mg, and 100.0% list L-Theanine (generic/unbranded) as the primary form.
Form share
Of 1,997 products with an identifiable primary form, here is the share held by each form of L-Theanine on the market today.
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| Form | Quality tier | n | Share |
|---|---|---|---|
| L-Theanine (generic/unbranded) | Tier 2 | 1,997 | 100.0% |
Forms we recognize but found no primary-form products for in this release: Suntheanine (branded, fermentation-derived), TheaPure L-Theanine (branded, HPLC-verified).
Form share over time
Entry-year breakdown of the top forms, 2012–2025.
Dose distribution
Deciles of declared dose per serving (mg), among 1,492 products with a disclosed amount.
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- 1.1% of products fall below the fairy-dust threshold (10 mg, 20% of the studied low dose).
- 25.1% of products don't disclose an amount because L-Theanine is declared inside a proprietary blend.
Where does your dose rank?
Enter a per-serving dose (mg) to see exactly how it compares to the 1,492 on-market l-theanine products with a disclosed amount. The chart above groups doses into deciles; this looks up the exact percentile for one number.
By dosage form
By target group
Top brands
Search interest over time
How often people search for l-theanine on Google, US only, the last 5 years. This is public interest, not DSLD label data — a spike here doesn't necessarily line up with anything on this page, and Google's own index (100 = that term's peak popularity in the chosen window) is relative, not an absolute search-volume count.
Or see this search directly on trends.google.com.
Forms explained
Chemically identical to branded forms when purity is verified; an industry-sourced report claimed some synthetic/generic products contained D-theanine (less well absorbed than L-theanine in rats), but independent confirmation is lacking -- quality may be manufacturer-dependent rather than guaranteed by the name alone.
Source: Desai MJ, Armstrong DW. 2005, Chirality 17:154-162, PMID 15704209 (rat PK of theanine enantiomers); the industry claim of racemic generic product is unconfirmed
The specific branded ingredient used as the study article in many published human L-theanine RCTs, giving it a deep clinical evidence trail among commercial forms; its >99% L-isomer purity is a manufacturer-sourced figure that was not independently verified. Superiority to a verified-pure generic is not confirmed by a head-to-head PK/outcomes trial -- this tier reflects depth of clinical usage, not proven PK superiority.
Source: used as the study article across many L-theanine RCTs; purity claim is manufacturer-sourced
No independent human clinical trials specific to this branded form were found.
Source: none found (PubMed search for TheaPure, Oct 2026)
Reference values
- RDA (adult): not established — Non-proteinogenic amino acid found in tea; no DRI exists.
- Tolerable Upper Intake Level (adult): not established — Not established. FDA has issued "no questions" letters on GRAS notices for L-theanine (e.g. Suntheanine) for specified food uses, which speaks to food-level safety, not a UL determination.
- Studied clinical dose range: 50–200 mg
- Lu K et al. 2004, Hum Psychopharmacol 19(7):457-65, PMID 15378679 -- RCT (n=16) repeated-measures, 200mg L-theanine vs 1mg alprazolam vs placebo; neither L-theanine nor alprazolam reduced anxiety under experimentally induced anticipatory anxiety, but L-theanine showed some relaxing effect under resting conditions (tranquil-troubled VAMS subscale). The 50mg low end is supported by Nobre AC, Rao A, Owen GN 2008, Asia Pac J Clin Nutr 17(Suppl 1):167-8, PMID 18296328 (50mg L-theanine increased EEG alpha activity, n=16 vs 19 placebo; a short report, not a clinical outcome).
- Note: An industry-sourced 2003 trade report claimed that some synthetic/generic L-theanine products contained D-theanine; D-theanine is less well absorbed than L-theanine in rats (Desai MJ, Armstrong DW. Chirality 2005;17:154-162, PMID 15704209). Independent confirmation of D/L contamination in retail products is lacking, so purity may be manufacturer-dependent rather than guaranteed by the name alone.