Green Tea Review: Tea Bags, Loose Tea, Matcha Powders, and Supplements

How Products Were Evaluated

Written by Mark Anderson, Ph.D. — Medically reviewed and edited by Tod Cooperman, M.D.

How Products were Selected:
Products tested represent those commonly sold and/or available nationally in the U.S. ConsumerLab.com purchased products on the open market through retail stores, on-line retailers, and direct sales companies. Products were not accepted directly from manufacturers.

Testing Methods:

Green tea (Camellia sinensis L.) products were tested in one or more independent laboratories for the following:

Total catechins (the sum of epigallocatechin, catechin, epicatechin, epigallocatechin-3-gallate, gallocatechin gallate, epicatechin-3-gallate, catechin gallate and gallocatechin) by high performance liquid chromatography (HPLC).*
Caffeine by HPLC*.
Quantitative analyses for lead, arsenic, and cadmium performed using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) for products containing whole herbs and/or more than 250 mg of minerals per daily dose.
Disintegration of tablets (excluding chewable, sublingual and time-release formulations) using United States Pharmacopeia (USP) <2040> methodology.

*Total catechins, caffeine, lead, cadmium and arsenic levels were also analyzed in the liquid of brewable teas after brewing. Teas were brewed using the following procedure: Boil 250mL DI water or tap water, remove from heat add 1 tea bag steep for 3 mins with slow stirring remove bag let cool. Transfer a portion to an injection vial and inject, without filtration or centrifugation. Transfer another portion to a separate vial for lead, cadmium and arsenic analysis. Results for brewable teas are reported per serving, adjusted to actual amounts of tea leaf in products.

Any product that did not initially pass (below) a test was sent to another independent laboratory to repeat testing for the criterion on which it did not pass.

ConsumerLab.com may modify or use other appropriate test methods if necessary to test special product formulations.

Identities of products were not disclosed to laboratories performing the testing.

Passing Score:*

To "Pass", a product had to meet all of the following requirements:

Contain a minimum of 100% and no more than 135% of label claim for total catechins or individual specific catechins (e.g. epigallocatechin gallate (EGCG)). Supplements containing green tea extracts with no total catechin or specific catechin label claim should have no less than 10% total catechins (%wt/wt). Supplements containing non-extracts of green tea with no total catechin or specific catechin label claim should have no less than 4% total catechins (%wt/wt). All green tea products must provide at least 20 mg EGCG per serving (lower amounts suggest questionable therapeutic value and/or quality).
Contain no less than 80% and no more than 120% of label claim for caffeine. For products claiming under 50 mg per serving, but not "caffeine free," within 10 mg of label claim. "Caffeine free" products must not contain more than 0.1% caffeine.
Heavy Metals: Products containing whole herbs and/or more than 250 mg of mineral per daily dose must not exceed the following limits:
Lead**:
- Products marketed for use by children may not exceed the State of California's Prop 65 limits for lead in dietary supplements of 0.5 mcg per recommended daily serving with an additional allowance of 0.8 mcg if the product contains more than 1,000 mg/day of calcium
- Supplements and matcha powders with single serving weights of less than 5 grams which are not marketed for use by children, may not exceed the State of California's Prop 65 limits for lead in dietary supplements of 0.5 mcg per recommended daily serving with an additional allowance of 0.4 mcg if containing 250-999 mg/day of any combination of elemental calcium, magnesium and potassium or 0.8 mcg if containing more than 1,000 mg/day of any combination of these minerals. An additional allowance of 0.5 mcg is provided if containing 250 to 999 mg/day of whole herb (not extract). However, total lead allowance will not exceed 2 mcg per day.
- Products with single serving weights of 5 grams or more which are not marketed for children may not exceed 2.5 mcg per serving nor 4.0 mcg per daily serving.
- In beverages and brewable teas (liquid portion). Lead must not exceed 1 mcg per suggested serving. (References: California Prop 65 limits for supplements (above), California Public Health Goals for Chemicals in Drinking Water of 0.5 mcg and 1.5 mcg lead per 250 mL (approx. 1 cup), respectively, as a neurobehavioral toxin and a carcinogen; U.S. EPA Maximum Contaminant Level Goal is zero for lead in drinking water but action level is 3.75 mcg per 250 mL.)
- In brewable teas (liquid portion). Lead must not exceed 1 mcg per suggested serving. (References: California Prop 65 limits for supplements (above), California Public Health Goals for Chemicals in Drinking Water of 0.5 mcg and 1.5 mcg lead per 250 mL (approx. 1 cup), respectively, as a neurobehavioral toxin and a carcinogen; U.S. EPA Maximum Contaminant Level Goal is zero for lead in drinking water but action level is 3.75 mcg per 250 mL.)
Cadmium**:
- If marketed for use by children, may not exceed 3.0 micrograms of cadmium per recommended daily serving (based on Canada's limit for a child weighing 75 lbs.). If not marketed for use by children, may not exceed 4.1 micrograms of cadmium per recommended daily serving (based on the State of California's Prop 65 limit).
Arsenic:
- Contain less than 10 micrograms of total arsenic and no more than 5 micrograms of inorganic arsenic per daily serving (EPA and state of New Jersey limits - based on 1 liter of water).
Meet recommended USP <2040> parameters for disintegration of dietary supplements (excluding capsule, chewable, sublingual and time-release products).
Be in compliance with l FDA labeling requirements.

* Passing scores allow for specific margins of technical error associated with each analysis. ConsumerLab.com reserves the right to disqualify a product at any time from passing its testing if it considers such product to display unacceptable variation, represent a safety risk or to provide misleading or inaccurate information in its labeling.

** The state of California Prop 65 limit. California requires products exceeding this limit to bear a warning label.

Back to review