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Nature’s Best L-Theanine 200 mg 200mg – Capsules
Product analysis · Nature’s Best

Nature’s Best L-Theanine 200 mg 200mg – Capsules

Tea-derived · Capsule

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.
Testing transparency: 9/20
£13.75Amazon
CapsuleFormat
200 mgDaily dose
60 capsulesPack size
£0.23Price/day
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The score, explained

Our scoring methodology
Testing & evidence45/100
9 points contributed · weighting 20
Ingredient/formulation quality84.1/100
21 points contributed · weighting 25
Value56/100
11 points contributed · weighting 20
Dose transparency97/100
15 points contributed · weighting 15
Manufacturer transparency85/100
9 points contributed · weighting 10
Label/ingredient transparency90.7/100
9 points contributed · weighting 10

The score compares product data, not medical effectiveness or individual suitability. Prime and affiliate commission contribute no points.

Testing & evidence

Testing claimed

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

Dose & value

Formulation
Tea-derivedCapsule
Daily dose
200 mgWithin recommended rangeTypical: 100–400 mg/day
Serving size
1 capsule
Pack size
60 capsules
Servings per day
1
Price per day
£0.23
Price last checked
2026-09-26 17:21:35

Daily cost uses the recorded label serving; a larger dose earns no value advantage. The label serving is not a recommendation for your personal intake.

L-theanine formulation details

Comparison form
Tea-derived
Named L-theanine ingredient
Not disclosed
Caffeine per serving (mg)
Not disclosed
Other active ingredients (summary)
Not disclosed
Standardisation / purity as labelled
Green tea leaf extract
L-theanine per serving as labelled
200 mg per serving
Serving as labelled
1 capsule
Daily amount (mg, single direction only)
200
Other active ingredients
None declared
Pack size as labelled
60 capsules
Recommended serving / frequency
Adults take 1 capsule daily, always with a meal
Allergen statement
Not disclosed
Vegan / vegetarian label status
Not disclosed

Ingredients & suitability

Excipients
Not disclosed — check the current label
Allergens
Not disclosed
Carrier / source
Not disclosed — check the current label
Other active ingredients
None declared

Manufacturer transparency

Brand
Nature’s Best
Legal company
Nature's Best
Manufacturing model
Not recorded
Manufacturing location
United Kingdom

View the full brand profile →

What the record makes clear

  • Active amount is disclosed.
  • Daily cost can be calculated from the recorded serving.

What to keep in mind

  • Verify the current label and the batch covered by any testing report.
  • A product score cannot determine whether you need a supplement.

Explore the alternatives

Compare alternative

Ambervit L-Theanine 400 mg 180 capsules 400mg – Capsules

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.
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
£0.11per day
£19.97per pack
View AnalysisBuy Nowon Amazon
Compare alternative

Ov OXFORD VITALITY Oxford Vitality L-Theanine & Caffeine 100mg – Capsules

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.
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
£0.03per day
£10.99per pack
View AnalysisBuy Nowon Amazon
Compare alternative

Nutrination L-Theanine 400 mg capsules 400mg – Capsules

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.
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
£0.07per day
£9.99per pack
View AnalysisBuy Nowon Amazon