Green Tea for Weight Control

Also indexed as:Camellia sinensis, EGCG
Green Tea
Green Tea: Main Image© Steven Foster

How Much Is Usually Taken by Dieters?

Test tube studies suggest that green tea extracts high in catechins may inhibit fat digestion and a preliminary human study found a green tea extract increased calorie burning.1, 2 A preliminary human study found that people taking a green tea extract containing 375 mg per day of total catechins (of which 270 mg per day was epigallocatechin gallate) for three months lost an average of 4.6% of their body weight without dieting.3 Double-blind trials are needed to confirm this effect.

Side Effects

Green tea is generally free of side effects. The most common adverse effects reported from consuming large amounts (several cups per day) of green tea are insomnia, anxiety, and other symptoms caused by the caffeine content in the herb.

An extract of green tea taken by healthy women with a meal inhibited the absorption of non-heme iron (e.g., the form of iron in plant foods) by 26%.4 Frequent use of green tea could, in theory, promote the development of iron deficiency in susceptible individuals.

There have been at least 34 case reports of people developing liver damage (sometimes severe) while consuming weight-loss products that contained concentrated extracts of green tea.5 A cause–effect relationship was not proven, and most of the products contained other ingredients in addition to green tea extract. However, researchers have concluded that green tea extract was the probable cause of liver damage in some of the cases.6 Scientists have cautioned against the use of large amounts, or concentrated extracts, of green tea. In addition, there is a case report in which a person developed thrombotic thrombocytopenic purpura (a condition in which a bruising develops as a result of a low platelet count) after consuming a weight-loss product that contained green tea extract for 2 months. Green tea was not proven to be the cause of this problem.7

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Interactions with Medicines

Certain medicines interact with this supplement.

Types of interactions:beneficial= Beneficialadverse= Adversecheck= Check
dnicon_BeneficialReplenish Depleted Nutrients


dnicon_BeneficialReduce Side Effects


dnicon_BeneficialSupport Medicine


dnicon_AvoidReduces Effectiveness
dnicon_AvoidPotential Negative Interaction


dnicon_CheckExplanation Required


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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2022.