Compare actual L-theanine mg per day. Tea extract, caffeine and other actives are kept separate, and a branded-ingredient claim is provenance, not automatic superiority. The amount is what the label states, not a dose-adequacy rating. Where directions give a range, the range is shown and daily cost uses the low end (no directions: one unit a day). Read the dose guide ↓

L-Theanine product comparison
#	Product	Formulation	Daily dose	Price/day	Testing	Score
1	Ambervit L-Theanine 400 mg 180 capsules 400mg – CapsulesAmbervit180 capsules	L-theanine aloneCapsule	400 mgWithin typical rangeTypical: 100–400 mg/day	£0.11per day£19.97 per packBuy Nowon Amazon	Testing evidence Evidence status Verified independent evidence Manufacturer statement Alpha01 product page for the same L-Theanine 400mg product lists 'CERTIFICATIONS & LAB TESTS' and links to batch-specific reports for 'Potency & Active Ingredient Testing', 'Heavy Metals Testing', and 'Microbial Contaminants Testing' for batch LC249531. Laboratory SIA "J.S. HAMILTON Baltic"; EUROFINS VITAMIN TESTING DENMARK A/S VEJEN Denmark Certification body Not recorded Batch LC249531/102028 Batch-specific report Recorded Report date Not recorded Evidence checked 2026-09-27 10:52:05 Certificate of analysis ↗ Laboratory report ↗ Manufacturer testing page ↗	Why this score? Testing & evidence 20/20 Ingredient/formulation quality 21/25 Value 15/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
2	Ov OXFORD VITALITY Oxford Vitality L-Theanine & Caffeine 100mg – CapsulesOv OXFORD VITALITY365 capsules	Blend With caffeineCapsuleCaffeine 50 mg	100 mgWithin typical rangeTypical: 100–400 mg/day	£0.03per day£10.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Amazon listing says: "Our supplements have been expertly created to the strictest GMP guidelines in our facility here in the UK, meaning we can guarantee the quality and safety of every product." Oxford Vitality product page also says "Quality Assured ✅" and the product description says the company "independently formulated" the product, but I did not find an independently verifiable third-party test/certification for this specific product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:48:55 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 20/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
3	Nutrination L-Theanine 400 mg capsules 400mg – CapsulesNutrination150 capsules	L-theanine aloneCapsule	400 mgWithin typical rangeTypical: 100–400 mg/day	£0.07per day£9.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Amazon listing and Nutri Nation site both claim testing/certification: Amazon title says "GMP - Certified, Lab Tested"; product imagery says "Third-party Lab Tested"; Nutri Nation site says "GMP CERTIFIED & THIRD PARTY TESTED" and "Made in the USA in NSF and ISO 17025 certified laboratories and third-party tested." I did not find an independently verifiable registry entry or product-specific COA for this exact L-Theanine product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:13:42 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 19/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
4	Best Naturals L-Theanine 200 mg tablets 200mg – TabletsOsavi Vitamin B6 P-5-P 30mg – 60 Vegan Capsules120 tablets	L-theanine aloneTablet	200 mgWithin typical rangeTypical: 100–400 mg/day	£0.08per day£9.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Manufacturer product page says: "3rd Party Lab Tested for Purity & Quality." Amazon listing also says: "3rd Party Lab Tested - Our All Best Naturals Products come with 3rd Party Independent Lab Tested." Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:53:23 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 17/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
5	Nutrivo L-Theanine 400 mg 120 capsules 400mg – CapsulesNutrivo120 capsules	L-theanine aloneCapsule	400 mgWithin typical rangeTypical: 100–400 mg/day	£0.08per day£9.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Amazon image says “Lab Tested” and “Independent Lab Tested”; Nutrivo product page says “Quality You Can Trust” and “carefully crafted to the highest standards,” but I did not find an independently verifiable COA, lab report, or certifying-body registry entry for this specific L-Theanine product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:07:30 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 17/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
6	Inca Naturals L-Theanine 450 mg 450mg – CapsulesInca Naturals120 capsules	BlendCapsuleVitamin B6 1.4 mg	450 mgAbove typical rangeTypical: 100–400 mg/day	£0.08per day£9.49 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Manufacturer site says the product is "3rd party tested" and the Amazon image says "TESTED FOR PURITY" / "Trusted quality from sourcing to capsule." I did not find an independently verifiable lab report or registry entry for this specific product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:11:47 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 18/20 Dose transparency 14/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
7	Vinco Supplements Vinco L-Theanine 400 mg 400mg – CapsulesVinco Supplements120 capsules	L-theanine aloneCapsule	400 mgWithin typical rangeTypical: 100–400 mg/day	£0.08per day£9.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Manufacturer pages claim the product is "GMP Certified" / made in "GMP-certified facilities" and the Amazon listing claims "99{3683f0b818e4e7eac3a25ad8212965194ab09621a23bd0189e97e17dfedff11f}+ Purity," but I did not find an independently verifiable third-party COA, lab report, or certification registry entry for this specific product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:09:28 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 17/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
8	Nutricost Caffeine 100mg – CapsulesNutricost240 capsules	Blend With caffeineCapsuleCaffeine 100 mg	100 mgWithin typical rangeTypical: 100–400 mg/day	£0.07per day£16.95 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Nutricost product page says: "Rigorous Testing: To guarantee the integrity of the product, each batch undergoes independent testing by third-party, ISO accredited laboratories." Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:44:36 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 18/20 Dose transparency 15/15 Manufacturer transparency 6/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
9	NutriVolv L-Theanine 400 mg 400mg – CapsulesNutriVolv120 capsules	BlendCapsuleBioPerine black pepper extract	400 mgWithin typical rangeTypical: 100–400 mg/day	£0.06per day£6.89 per packBuy Nowon Amazon	Testing evidence Evidence status No public evidence located Manufacturer statement Not recorded Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:10:36	Why this score? Testing & evidence 4/20 Ingredient/formulation quality 21/25 Value 19/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
10	Redwells L-Theanine 300 mg 120 capsules 300mg – CapsulesRedwells120 capsules	L-theanine aloneCapsule	300 mgWithin typical rangeTypical: 100–400 mg/day	£0.12per day£14.95 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement REDWELLS quality page says: "COA Available on Request" and "Certificates of Analysis can be requested for available product batches"; it also lists L-Theanine with a latest batch number (20250605). This is a testing/COA claim, but I did not find an independently verifiable COA or registry entry for the specific Amazon capsule product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:43:47 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 13/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
11	Life Essentials L-Theanine 200 mg 200mg – CapsulesLife Essentials120 capsules	L-theanine aloneCapsule	200–400 mgWithin typical rangeTypical: 100–400 mg/day	£0.08per day£9.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Amazon listing and product page claim: "Every batch is lab-tested using HPLC measuring method to ensure purity and potency you can rely on"; product page also shows a "Lab Reports" page, but no specific report for this product was accessible in the page text I read. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:02:58 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 17/20 Dose transparency 11/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
12	New Leaf Products L-Theanine 400 mg 400mg – CapsulesNew Leaf Products120 capsules	BlendCapsuleVitamin B6 4 mg	400 mgWithin typical rangeTypical: 100–400 mg/day	£0.16per day£9.49 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Manufacturer site says: "To ensure the highest safety and quality, our products undergo rigorous testing for heavy metals and unwanted compounds during production to fully comply with global regulations." Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:06:41 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 12/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
13	Alpha01 Organic L-Theanine 400 mg from green tea extract 400mg – CapsulesAlpha0160 capsules	Not disclosedCapsule	Amount not stated	£0.25per day£14.99 per packBuy Nowon Amazon	Testing evidence Evidence status Verified independent evidence Manufacturer statement Manufacturer page states: "CERTIFICATIONS & LAB TESTS" for Alpha01 L-Theanine Amino Acid 400mg, with linked reports for "Potency & Active Ingredient Testing," "Heavy Metals Testing," and "Microbial Contaminants Testing" for batch LC249531. The linked reports show the sample description "Alpha01 - L-Theanine Amino Acid Capsules 400mg" and independent lab testing by J.S. Hamilton Baltic / Eurofins Vitamin Testing Denmark A/S. Laboratory SIA "J.S. HAMILTON Baltic"; EUROFINS VITAMIN TESTING DENMARK A/S Certification body Not recorded Batch LC249531/102028 Batch-specific report Recorded Report date Not recorded Evidence checked 2026-09-27 10:58:14 Certificate of analysis ↗ Laboratory report ↗ Manufacturer testing page ↗	Why this score? Testing & evidence 20/20 Ingredient/formulation quality 16/25 Value 15/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 0/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
14	Health Thru Nutrition L-Theanine 200 mg PhytoSure 200mg – CapsulesHealth Thru Nutrition60 capsules	L-theanine aloneCapsule	200 mgWithin typical rangeTypical: 100–400 mg/day	£0.23per day£13.95 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Manufacturer site says: "Our comprehensive, four-stage testing protocol ensures exceptional purity, potency, and safety from ingredients to final products. Every step is meticulously designed to meet the highest industry standards" and "our products undergo strict testing to qualify purity and stability"; the product page also says "3rd Party Tested" and "PhytoSure Certified." Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:57:13 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 11/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
15	Alpha01 L-Theanine 400 mg from green tea 400mg – CapsulesAlpha0190 capsules	Not disclosedCapsule	Amount not stated	£0.22per day£9.99 per packBuy Nowon Amazon	Testing evidence Evidence status Verified independent evidence Manufacturer statement Manufacturer product page says: "CERTIFICATIONS & LAB TESTS" with entries for "Potency & Active Ingredient Testing," "Heavy Metals Testing," and "Microbial Contaminants Testing" for batch LC249531, and the linked reports show testing performed by independent labs (e.g. "Test: Theanine was performed in laboratory EUROFINS VITAMIN TESTING DENMARK A/S VEJEN Denmark" and a separate J.S. Hamilton Baltic report for heavy metals/microbiology). Laboratory Eurofins Vitamin Testing Denmark A/S Certification body Not recorded Batch LC249531/102028 Batch-specific report Recorded Report date Not recorded Evidence checked 2026-09-27 11:05:45 Certificate of analysis ↗ Laboratory report ↗ Manufacturer testing page ↗	Why this score? Testing & evidence 19/20 Ingredient/formulation quality 16/25 Value 15/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 0/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
16	Nature’s Best L-Theanine 200 mg 200mg – CapsulesNature’s Best60 capsules	Tea-derivedCapsule	200 mgWithin typical rangeTypical: 100–400 mg/day	£0.23per day£13.75 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Nature's Best says on its own site: "Every one of our supplements is crafted, tested, and packaged right here in the UK." The L-Theanine product page also says the capsules are "highly absorbable" and made with "stringent ingredient standards," but I did not find any independently verifiable third-party COA or certification for this specific product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:05:09 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 11/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
17	Ambervit L-Theanine 200 mg 180 capsules 200mg – CapsulesAmbervit180 capsules	L-theanine aloneCapsule	200–400 mgWithin typical rangeTypical: 100–400 mg/day	£0.11per day£19.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Amazon listing images/text show a generic badge reading "LAB TESTED" for Ambervit L-Theanine 200mg 180 capsules, but I did not find any independently verifiable COA, lab report, or certifying-body registry entry for this specific product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:02:18 Amazon listing (claim source) ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 14/20 Dose transparency 11/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
18	Vitmad L-Theanine 500 mg 90 capsules 500mg – CapsulesVitmad90 capsules	L-theanine aloneCapsule	500 mgAbove typical rangeTypical: 100–400 mg/day	£0.08per day£7.39 per packBuy Nowon Amazon	Testing evidence Evidence status No public evidence located Manufacturer statement Not recorded Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:00:02	Why this score? Testing & evidence 4/20 Ingredient/formulation quality 21/25 Value 17/20 Dose transparency 14/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
19	Time Health L-Theanine Green Tea Extract 300mg – CapsulesTime Health120 capsules	Tea-derivedCapsule	300 mgWithin typical rangeTypical: 100–400 mg/day	£0.37per day£22.49 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Time Health product page says: "Third Party Test Report" and shows a "Heavy Metal Analysis" section, but I did not find a readable product-specific report for the L-Theanine item itself or an independently verifiable third-party registry entry for this product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:54:44 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 10/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
20	Doctor’s BEST L-Theanine AlphaWave 200mg – CapsulesDoctor’s Best60 capsules	L-theanine alone Named ingredientCapsuleAlphaWave	200 mgWithin typical rangeTypical: 100–400 mg/day	£0.36per day£21.50 per packBuy Nowon Amazon	Testing evidence Evidence status No public evidence located Manufacturer statement Not recorded Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:46:23	Why this score? Testing & evidence 4/20 Ingredient/formulation quality 23/25 Value 10/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 10/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
21	5greens L-Theanine 500 mg 120 capsules 500mg – Capsules5greens120 capsules	L-theanine aloneCapsule	500–1,000 mgAbove typical rangeTypical: 100–400 mg/day	£0.14per day£16.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Manufacturer site has a specific testing claim for a different product: "5greens Chlorella Tablets 100{3683f0b818e4e7eac3a25ad8212965194ab09621a23bd0189e97e17dfedff11f} Chlorella Heavy Metal Tested". For the L-Theanine product itself, the product page only says "No Fillers No Nasty Chemicals 100{3683f0b818e4e7eac3a25ad8212965194ab09621a23bd0189e97e17dfedff11f} Active Content" and similar marketing language, with no actual testing/certification claim found for this item. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:57:41 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 21/25 Value 13/20 Dose transparency 10/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
22	Pure Encapsulations L-Theanine 200mg – CapsulesPure Encapsulations60 capsules	L-theanine alone Named ingredientCapsuleSuntheanine	200–400 mgWithin typical rangeTypical: 100–400 mg/day	£0.86per day£51.85 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Pure Encapsulations’ Quality Assurance page says: “All raw materials and finished products are independently tested for purity and potency by our third-party laboratories” and the product page for l-Theanine says it is “carefully manufactured and tested to verify their potency and purity.” Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:04:02 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 23/25 Value 9/20 Dose transparency 11/15 Manufacturer transparency 9/10 Label/ingredient transparency 10/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
23	Bespoke Biotics NOOROPOWER Zen L-Theanine 250 mg 250mg – CapsulesBespoke Biotics120 capsules	L-theanine aloneCapsule	500 mgAbove typical rangeTypical: 100–400 mg/day	£0.22per day£13.19 per packBuy Nowon Amazon	Testing evidence Evidence status No public evidence located Manufacturer statement Not recorded Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:48:04	Why this score? Testing & evidence 4/20 Ingredient/formulation quality 21/25 Value 12/20 Dose transparency 14/15 Manufacturer transparency 9/10 Label/ingredient transparency 9/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
24	Focus FS L-Theanine 300 mg from green tea extract 300mg – CapsulesFocus180 capsules	Not disclosedCapsule	Amount not stated	£0.33per day£29.99 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement Focus Supplements says: "Every batch is tested for heavy metals and microbiological organisms. In the name of total transparency, we provide certificates of analysis for every supplement. Drop us a message at support@focussupplements.co.uk to request one." Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 10:50:15 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 16/25 Value 15/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 0/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.
25	WeightWorld L-Theanine 401 mg 401mg – CapsulesWeightWorld180 capsules	Not disclosedCapsule	Amount not stated	£0.09per day£15.49 per packBuy Nowon Amazon	Testing evidence Evidence status Testing claimed Manufacturer statement WeightWorld’s product page says the capsules are part of its 'Third-Party Tested' range and that 'we send our supplements to accredited third-party laboratories to verify purity and quality without any internal bias.' However, I did not find an independently verifiable lab report or certification for this specific L-Theanine product. Laboratory Not recorded Certification body Not recorded Batch Not recorded Batch-specific report Not established in this record Report date Not recorded Evidence checked 2026-09-27 11:12:48 Manufacturer testing page ↗	Why this score? Testing & evidence 9/20 Ingredient/formulation quality 16/25 Value 15/20 Dose transparency 15/15 Manufacturer transparency 9/10 Label/ingredient transparency 0/10 Displayed points and weights are rounded; the total uses unrounded weights. Pending dimensions are excluded. Provisional scores may change after review.

Formulation: L-theanine aloneCapsule
Daily dose: 400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 180 capsules

Full ingredients and formulation →

£0.11per day£19.97 per pack

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Formulation: Blend With caffeineCapsuleCaffeine 50 mg
Daily dose: 100 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 365 capsules

Full ingredients and formulation →

£0.03per day£10.99 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneCapsule
Daily dose: 400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 150 capsules

Full ingredients and formulation →

£0.07per day£9.99 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneTablet
Daily dose: 200 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Tablet
Serving: 1 tablet
Servings/day: 1
Pack size: 120 tablets

Full ingredients and formulation →

£0.08per day£9.99 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneCapsule
Daily dose: 400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 120 capsules

Full ingredients and formulation →

£0.08per day£9.99 per pack

View Analysis Buy Now on Amazon

Formulation: BlendCapsuleVitamin B6 1.4 mg
Daily dose: 450 mgAbove typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 120 capsules

Full ingredients and formulation →

£0.08per day£9.49 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneCapsule
Daily dose: 400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 120 capsules

Full ingredients and formulation →

£0.08per day£9.99 per pack

View Analysis Buy Now on Amazon

Formulation: Blend With caffeineCapsuleCaffeine 100 mg
Daily dose: 100 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 240 capsules

Full ingredients and formulation →

£0.07per day£16.95 per pack

View Analysis Buy Now on Amazon

Formulation: BlendCapsuleBioPerine black pepper extract
Daily dose: 400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 120 capsules

Full ingredients and formulation →

£0.06per day£6.89 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneCapsule
Daily dose: 300 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 120 capsules

Full ingredients and formulation →

£0.12per day£14.95 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneCapsule
Daily dose: 200–400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: Not disclosed
Pack size: 120 capsules

Full ingredients and formulation →

£0.08per day£9.99 per pack

View Analysis Buy Now on Amazon

Formulation: BlendCapsuleVitamin B6 4 mg
Daily dose: 400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 2 capsules
Servings/day: 1
Pack size: 120 capsules

Full ingredients and formulation →

£0.16per day£9.49 per pack

View Analysis Buy Now on Amazon

Formulation: Not disclosedCapsule
Daily dose: Amount not stated

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 60 capsules

Full ingredients and formulation →

£0.25per day£14.99 per pack

View Analysis Buy Now on Amazon

Formulation: L-theanine aloneCapsule
Daily dose: 200 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 60 capsules

Full ingredients and formulation →

£0.23per day£13.95 per pack

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Formulation: Not disclosedCapsule
Daily dose: Amount not stated

Formulation & serving details

Format: Capsule
Serving: 2 capsules
Servings/day: 1
Pack size: 90 capsules

Full ingredients and formulation →

£0.22per day£9.99 per pack

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Formulation: Tea-derivedCapsule
Daily dose: 200 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 60 capsules

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£0.23per day£13.75 per pack

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Formulation: L-theanine aloneCapsule
Daily dose: 200–400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: Not disclosed
Pack size: 180 capsules

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£0.11per day£19.99 per pack

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Formulation: L-theanine aloneCapsule
Daily dose: 500 mgAbove typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 90 capsules

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£0.08per day£7.39 per pack

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Formulation: Tea-derivedCapsule
Daily dose: 300 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 2 capsules
Servings/day: 1
Pack size: 120 capsules

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£0.37per day£22.49 per pack

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Formulation: L-theanine alone Named ingredientCapsuleAlphaWave
Daily dose: 200 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 60 capsules

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£0.36per day£21.50 per pack

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Formulation: L-theanine aloneCapsule
Daily dose: 500–1,000 mgAbove typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: Not disclosed
Pack size: 120 capsules

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£0.14per day£16.99 per pack

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Formulation: L-theanine alone Named ingredientCapsuleSuntheanine
Daily dose: 200–400 mgWithin typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: Not disclosed
Pack size: 60 capsules

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£0.86per day£51.85 per pack

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Formulation: L-theanine aloneCapsule
Daily dose: 500 mgAbove typical rangeTypical: 100–400 mg/day

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 2
Pack size: 120 capsules

Full ingredients and formulation →

£0.22per day£13.19 per pack

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Formulation: Not disclosedCapsule
Daily dose: Amount not stated

Formulation & serving details

Format: Capsule
Serving: 2 capsules
Servings/day: 1
Pack size: 180 capsules

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£0.33per day£29.99 per pack

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Formulation: Not disclosedCapsule
Daily dose: Amount not stated

Formulation & serving details

Format: Capsule
Serving: 1 capsule
Servings/day: 1
Pack size: 180 capsules

Full ingredients and formulation →

£0.09per day£15.49 per pack

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One-time purchase prices; delivery and conditional discounts excluded. Daily cost uses the recorded label serving. Comparison amounts are not personal dose recommendations. Unknown Prime eligibility is not treated as confirmed.

L-theanine forms and labels explained

L-theanine products differ mainly by dose, whether the ingredient is isolated or tea-derived, and whether caffeine or other actives are present. Compare the measured L-theanine first.

L-theanine alone

Single-active formulation

Compare: L-theanine mg
Caffeine: None declared

Best match for trials designed to test L-theanine without stimulant co-actives.

L-theanine from tea extract

Tea-derived source

Main dose: Actual L-theanine
Keep separate: Tea-extract weight

A large tea-extract or leaf-equivalent number does not replace the quantified L-theanine amount.

L-theanine plus caffeine

Combination formulation

Record: Both active doses
Evidence: Combination-specific

Acute attention evidence should not be transferred to caffeine-free L-theanine products.

Named L-theanine ingredient

Trademarked raw material

Usefulness: Study traceability
Not automatic: Higher quality

A branded ingredient may match a trial, but the finished product still needs its own quality evidence.

Multi-ingredient blend

Sleep, calm or nootropic blend

Compare: Every active separately
Avoid: Blend-mass dosing

Do not attribute effects of magnesium, herbs, caffeine or vitamins to L-theanine.

L-theanine dose: study amounts, not a universal target

No NHS/FSA L-theanine RNI, NRV or formal upper limit was identified in the official UK sources checked. The FSA's general advice is to follow the product's labelled directions and not exceed them. [1]

Research amounts vary by outcome and design. Standalone studies have used 200 mg/day for four weeks and 200 mg/day of a named ingredient for 28 days, while acute cognition studies have used 250 mg alone. [3] [4] [6] A 2025 sleep review included standalone doses from 50 to 900 mg/day and described 200–450 mg/day as promising in adults, but this is a research synthesis rather than a UK recommendation. [8]

What the L-theanine evidence shows

Evidence is clearest when L-theanine alone and caffeine combinations are kept separate. Short standalone trials suggest possible improvements in stress-related symptoms, selected sleep outcomes and some attention measures, but samples are small and durations are short. [3] [4] [10]

For acute attention, several studies show benefits from L-theanine plus caffeine. A 44-person study using 97 mg L-theanine with 40 mg caffeine improved selected task-switching and alertness outcomes. [5] That result should not be presented as proof that caffeine-free L-theanine has the same effect.

L-theanine evidence by goal

Evidence by goal
Goal	Evidence strength	What was assessed	Typical study context	Main limitation
Stress-related symptoms	Promising but limited	Standalone L-theanine	Small adult trials around 200 mg/day for 4 weeks.	Short duration, modest samples and multiple outcomes.
Sleep	Promising, not definitive	Standalone L-theanine across 13 trials	Systematic review: 550 participants; 50–900 mg/day across studies.	Heterogeneous designs, two open-label studies and limited clinical-insomnia evidence.
Acute focus/attention	Better supported for caffeine combination than L-theanine alone	L-theanine + caffeine	One trial used 97 mg L-theanine + 40 mg caffeine in 44 young adults.	Combination effect cannot be assigned to L-theanine alone.
Attention/working memory without caffeine	Limited	Standalone L-theanine	Small controlled studies report selected attention/working-memory effects.	Population/test-specific, small studies and not a broad nootropic effect.

Read the full evidence-by-goal detail

Stress and calm

Standalone 200 mg/day studies report improvements in selected stress-related outcomes over roughly four weeks, but evidence is not large or long-term. [3] [4]

Sleep

A 2025 systematic review identified 13 standalone L-theanine sleep trials involving 550 participants. Results were promising across several objective and self-reported measures, but more high-quality trials are needed, particularly in clinical insomnia. [8]

Focus and attention

Some attention evidence involves L-theanine alone, but much of the acute cognitive literature uses caffeine combinations. [5] [6] [7] These formulations should be compared separately.

When to take L-theanine

No universal morning or evening timing rule is established. Acute attention studies dose L-theanine before cognitive testing, while sleep studies use different schedules. Follow the product label unless a healthcare professional advises otherwise. [8]

If a product contains caffeine, its caffeine amount and timing matter independently from L-theanine.

L-theanine safety and interaction context

Who should be cautious?If any of the following apply to you, speak to a healthcare professional before taking L-Theanine - see the full detail below for why.

Pregnant or breastfeeding people
People taking regular prescription medicines
People with medical conditions where sedative, stimulant or blood-pressure effects could matter
People using caffeine-containing L-theanine combinations who are sensitive to caffeine

Short adult trials generally report good tolerability, but longer-term evidence is limited. [4] [8] [9] No formal UK L-theanine upper limit was identified.

The FSA advises people who are pregnant, breastfeeding, taking regular medicines or living with medical conditions to discuss supplements with a healthcare professional. [1] No authoritative universal drug-separation interval for L-theanine was identified.

L-theanine with caffeine and other ingredients

L-theanine is often paired with caffeine, green-tea extract, vitamin B6, magnesium or calming herbs. Record each active separately. Evidence from an L-theanine + caffeine trial cannot be used as if it tested L-theanine alone. [5] [7]

The current GB claims register also means concentration/attention marketing should not be treated as an authorised L-theanine health claim merely because a study exists. [2]

Who might consider L-theanine

Adults interested in stress, sleep or attention can use this comparison to see which products match the formulations actually studied, but the evidence remains modest and short-term. [3] [8] People seeking treatment for anxiety disorders, insomnia or another diagnosed condition should not use a retail comparison as a substitute for care.

How to compare L-theanine testing evidence

Useful testing evidence confirms L-theanine identity and potency in the finished product, not merely the weight of a tea extract or blend. Caffeine should also be measured or clearly disclosed where it is part of the formulation or where a caffeine-free claim matters.

Named raw materials can improve traceability to a study, but a trademark is not itself independent testing or proof of superiority. The Supplement Compare testing guide explains how testing claims, COAs and stronger independent evidence are separated. Read the guide

Testing evidence in this comparison

A testing claim is not the same as a verified report. No public evidence located does not mean a product has not been tested.

Testing review pending0

Recognised certification0

Verified independent evidence3

Manufacturer COA0

Testing claimed18

No public evidence located4

What does l-theanine cost?

Current UK comparison set, based on the daily serving shown on each label.

£0.03Lowest daily cost

£0.11Median daily cost

£0.86Highest daily cost

Your questions, answered

What is a typical L-theanine dose?

There is no official UK recommended L-theanine dose. Human studies commonly test 200 mg or other study-specific amounts, and a recent sleep review included 50–900 mg/day. [3] [8] Those are research exposures, not a universal recommendation.

Is L-theanine better with caffeine?

For acute attention, several studies found benefits from the combination. One used 97 mg L-theanine with 40 mg caffeine. [5] That does not mean everyone should add caffeine, and combination evidence should not be credited to caffeine-free products.

Does L-theanine help sleep?

A 2025 systematic review found promising results across 13 standalone L-theanine trials, but the authors also called for more high-quality objective studies and research in clinical insomnia. [8]

Is 400 mg L-theanine too much?

No formal UK upper limit was identified. Some commercial products supply 400 mg per serving and short-term research has used doses in this range, but that is not the same as proving 400 mg is appropriate or safe for everyone. [12] [9]

Is tea extract the same as L-theanine?

No. A tea extract can contain L-theanine plus other tea compounds. Use the amount specifically declared as L-theanine. One current UK product separately lists 200 mg L-theanine and green-tea-derived components. [11]

Sources & methodology

Read our methodology and how we verify testing.

Page updated26 Sep 2026

Editorial reviewSources checked 2026-09-26; editorial preview

Product evidenceSee individual records

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L-theanine forms and labels explained

L-theanine alone

L-theanine from tea extract

L-theanine plus caffeine

Named L-theanine ingredient

Multi-ingredient blend

L-theanine dose: study amounts, not a universal target

What the L-theanine evidence shows

L-theanine evidence by goal

Stress and calm

Sleep

Focus and attention

When to take L-theanine

L-theanine safety and interaction context

L-theanine with caffeine and other ingredients

Who might consider L-theanine

How to compare L-theanine testing evidence

Testing evidence in this comparison

What does l-theanine cost?

Your questions, answered

Sources & methodology