The 3 Best L-Theanine Supplements of 2026
The best L-theanine for most people is Momentous L-Theanine 200 mg: 200 mg a capsule, $0.67 per 200 mg. It is on NSF Certified for Sport and NSF/ANSI 173, lists that check what is in the bottle. For the lowest cost, Horbaach L-Theanine 400 mg per serving gives the same 200 mg for $0.087.
By Erin Rose Updated October 7, 2026 How we score
Prices are each brand’s own list price; other stores may differ.
Our pick for: Most people
Good
- On the NSF Certified for Sport and NSF/ANSI 173 lists (checked October 7, 2026)
- Trial-sized serving: 200 mg per serving (we count 100 mg or more)
- Label states the amount, with no blend
Watch for
- Costs 8 times as much per dose as the cheapest of its kind we score
- L-theanine
- 200 mgin 1 capsule
- Per 200 mg
- $0.67at the brand’s list price
- Testing lists
- NSF Certified for Sportand NSF/ANSI 173, checked October 7, 2026
- Bottle
- 60 capsules, $39.99Momentous’ own store price
Our take
Why we pick it One capsule gives 200 mg, the single dose trials used most. It is on NSF Certified for Sport, which also screens for substances banned in sport, and on NSF/ANSI 173, which checks that the bottle holds what the label says. It ties Thorne on our score and costs less: $0.67 per 200 mg against $0.76.
What you give up Price. If you only want the lowest cost, Horbaach L-Theanine 400 mg per serving is $0.087 per 200 mg (below).
Testing record
- NSF Certified for Sport: banned substances, by lot See the listing Checked October 7, 2026.
- NSF/ANSI 173: contents match the label Checked October 7, 2026.
Not found on: Informed Sport, Informed Choice, USP Verified.
Our other 2 picks
- Suntheanine, on a testing list Thorne Theanine 200 mg
- Lowest cost Horbaach L-Theanine 400 mg per serving
Our pick for: Suntheanine, on a testing list
Good
- On the NSF/ANSI 173 list (checked October 7, 2026)
- Trial-sized serving: 200 mg per serving (we count 100 mg or more)
- Label states the amount, with no blend
Watch for
- Costs 9.1 times as much per dose as the cheapest of its kind we score
- L-theanine
- 200 mgin 1 capsule
- Per 200 mg
- $0.76at the brand’s list price
- Testing list
- NSF/ANSI 173checked October 7, 2026
- Form
- Suntheanineper NIH’s label database
Our take
Why we pick it NIH’s label database lists Suntheanine, a branded L-theanine made by Taiyo Kagaku, for this capsule. It is on NSF/ANSI 173, which checks the contents. 200 mg a capsule, $0.76 per 200 mg.
What you give up It costs the most of our three picks, and it is not on NSF Certified for Sport.
Testing record
- NSF/ANSI 173: contents match the label Checked October 7, 2026.
Not found on: NSF Certified for Sport, Informed Sport, Informed Choice, USP Verified.
Our pick for: Lowest cost
Horbaach L-Theanine 400 mg per serving
7.0/10 Our score
Good
- Trial-sized serving: 400 mg per serving (we count 100 mg or more)
- Close to the lowest cost per dose (1.05 times the cheapest of its kind we score)
- Label states the amount, with no blend
Watch for
- Not on any public testing list we check
- L-theanine
- 400 mgin 2 capsules
- Per 200 mg
- $0.087at the brand’s list price
- Testing list
- Not on one we checkedOctober 7, 2026
- Bottle
- 120 capsules (60 servings), $10.49Horbaach’s own store price
Our take
Why we pick it The lowest cost per 200 mg of any capsule bottle we score: $0.087, about an eighth of our main pick. One capsule is 200 mg.
What you give up It is not on a public testing list, so no outside program has checked the bottle.
Testing record
Not found on any testing list we check.
Not found on: NSF Certified for Sport, Informed Sport, Informed Choice, NSF/ANSI 173, USP Verified.
Which one is for you?
Most trials gave one 200 mg dose to healthy adults and measured things like attention tasks and stress ratings; results were small and mixed (what the trials measured). If you want to try it, one 200 mg capsule matches what most trials used (how much to take).
| Your situation | What to buy |
|---|---|
| You want a product on a testing list | Momentous L-Theanine 200 mg, $0.67 (our pick) |
| You are drug-tested in your sport | Momentous L-Theanine 200 mg, the only one we score on NSF Certified for Sport (our pick) |
| You want Suntheanine | Thorne Theanine 200 mg, $0.76 (above) |
| You want the lowest cost | Horbaach L-Theanine 400 mg per serving, $0.087 (above) |
| You want it with caffeine in one pill | Nutricost Caffeine with L-Theanine 100 mg each: 100 mg of L-theanine and 100 mg of caffeine a capsule, $0.13 |
| You want a chewable | Nature Made Chewable L-Theanine 200 mg: 200 mg a tablet, $0.34 |
| You are fine measuring a powder | BulkSupplements L-Theanine Powder: $0.020 per 200 mg, the lowest cost we found |
| You already buy NOW Foods | NOW L-Theanine 200 mg with Inositol: $0.38; each capsule also has inositol |
Suntheanine or plain L-theanine?
Suntheanine is a branded L-theanine made by Taiyo Kagaku. Taiyo funded or supplied some trials; in one, it supplied the tablets (Hidese 2019). It is the same molecule as plain L-theanine; we found no trial that compared the two. 4 of the 23 labels we score name Suntheanine. Some labels name AlphaWave, another branded L-theanine. Most name no source. Who funded each trial.
Read the label: the serving can be 2 pieces
The big number on the front is for one serving, and a serving can be 2 capsules or 2 gummies. Our costs are per 200 mg, so they already account for this. How many capsules make 200 mg.
How other guides picked
Other guides we read on October 7, 2026 pick Momentous (Straight.com), Thorne (FitnessVolt, Body Science Review) and Nature’s Trove (Best For Nutrition). On our measures, Thorne Theanine is on NSF/ANSI 173 but not on NSF Certified for Sport, and Nature’s Trove is not on a testing list we checked.
How we score
We scored 23 L-theanine products in all; the picks and the table above are the best of each kind.
The score. Five marks: does a serving give at least 100 mg of L-theanine, which we count as trial-sized (trials used 50 to 400 mg in one dose; this line is ours, not an official one); is the product on a public testing list (a brand’s own testing claim, with no listing, earns half the points); what 200 mg costs against the cheapest in its group; does the label state the amount with no blend; and the brand’s FDA record. Dose and testing are worth up to 3 points each, cost up to 2, label and FDA record up to 1 each, for 10 in all. Scores updated October 7, 2026. How we score.
Not scored, and why.
- Pure Encapsulations L-Theanine (60 capsules): No list price we can cite: the brand sells through practitioners and we do not use Amazon prices. Its NIH label gives 200 mg of Suntheanine a capsule (400 mg in 2).
- Integrative Therapeutics L-Theanine (60 capsules): A practitioner brand: its page shows $22.00 next to 'Sign in' and 'How To Order', so we could not confirm a price a shopper can pay. Label: 200 mg in 2 capsules.
- Solgar L-Theanine 150 mg (60 veg capsules): We could not read Solgar's store, so we have no list price. Its NIH label gives 150 mg of Suntheanine a capsule.
- Natural Factors Suntheanine 200 mg chewable (60 tablets): We found no Natural Factors US store page to price it (only a retailer). The label is 200 mg in 2 chewable tablets (100 mg a tablet), Suntheanine, 3 g added sugar.
- Sports Research L-Theanine + Caffeine (60 softgels): We could not read the brand's store, so we have no list price. Its NIH label gives 200 mg AlphaWave L-theanine and 100 mg caffeine a softgel.
What the trials measured
Most L-theanine trials are small, one-dose tests in healthy adults. They measured reaction time, attention tasks, brain waves and questionnaires, often with caffeine. Results are small and mixed. Every trial, with its funder, how much to take and side effects.
Sources
- Hidese S 2019, Nutrients. PubMed 31623400
- Other guides, read October 7, 2026: Straight.com, FitnessVolt, Body Science Review and Best For Nutrition.
- Labels: each brand’s page or the NIH Dietary Supplement Label Database. Testing: NSF/ANSI 173 (Thorne listing), NSF Certified for Sport (listing 1600891), Informed Choice and Informed Sport, read October 7, 2026; USP Verified from our copy of September 22, 2026. Prices: each brand’s own list price, checked October 7, 2026.