Longer Living Guide

Nature's Best

Nature’s Best L-Theanine 200mg

Early research
£12.50at naturesbest.co.uk

Best for: People whose sleep problem is a busy, wound-up mind at bedtime

Price checked

Buy now at naturesbest.co.uk
  • 200mg L-theanine per capsule
  • Single ingredient

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200mg L-theanine per capsule

Dose
200mg per capsule
Pack
60 or 120 capsules
Source
Green tea derived (stated)

Where we checked it: naturesbest.co.uk ›

Why we picked it

A single-ingredient 200mg capsule, the dose used in many trials, at a low price. A 2025 meta-analysis of 18 trials found small improvements in how quickly people felt they fell asleep and how they rated their sleep.

Best for

People whose sleep problem is a busy, wound-up mind at bedtime

Not for

Anyone pregnant or breastfeeding, or taking blood pressure medicine or sedatives without checking first

The details that matter.

  • • 200mg L-theanine per capsule
  • • Single ingredient
  • • 60 or 120 capsules
  • • UK brand with direct sales

Specifications

Dose
200mg per capsule
Pack
60 or 120 capsules
Source
Green tea derived (stated)
Third party testing
None published
How strong is the research? What our grades mean ›
Strong research
Independent certification or lab data for the specific claim.
Promising research
The material is well supported, but there is no product-level testing.
Early research
Little independent research.
Mixed research
Research findings disagree.
£
Under £20
££
£20 to £79
£££
£80+

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Sources

  1. naturesbest.co.uk
  2. pubmed.ncbi.nlm.nih.gov