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Weight LossModerate Evidence3rd Party Tested

Green Tea Extract

Also known as: GTE, EGCG, Epigallocatechin Gallate, Camellia sinensis

A thermogenic polyphenol with synergistic fat-burning properties

7/10 Evidence Score

Primary Benefit

Thermogenesis & Fat Oxidation

Standard Dose

400 to 500 mg EGCG per day

Evidence

Certifications

USP VerifiedInformed Sport

Overview

Green tea extract is concentrated from the leaves of Camellia sinensis and standardized for its active compounds, particularly epigallocatechin gallate (EGCG) and caffeine. The combination inhibits the enzyme catechol-O-methyltransferase (COMT), which prolongs norepinephrine signaling and sustains fat-burning, making it more effective than either compound alone.

Benefits & Evidence

  • Inhibits COMT enzyme, prolonging fat-burning norepinephrine signaling
  • Increases 24-hour energy expenditure by 3 to 4 percent
  • Enhances fat oxidation, particularly during exercise
  • Provides antioxidant protection via polyphenols
  • May reduce visceral (abdominal) fat specifically

Clinical Study Summaries

Green tea extract thermogenesis-induced weight loss by epigallocatechin gallate inhibition of catechol-O-methyltransferase

1999

Journal of Nutritional Biochemistry

EGCG inhibited COMT activity, increasing thermogenesis and fat oxidation beyond caffeine alone, establishing a distinct fat-burning mechanism.

Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure

1999

American Journal of Clinical Nutrition

24-hour energy expenditure increased by 4 percent and fat oxidation by 10 percent compared to placebo in a controlled metabolic chamber study.

View study

Recommended Dosage

Standard Dose400 to 500 mg EGCG per day
Minimum270 mg EGCG
Maximum800 mg EGCG/day
TimingWith meals to reduce GI discomfort; avoid on an empty stomach
Notes: Look for extracts standardized to at least 50 percent EGCG. Taking with caffeine amplifies thermogenic effects.

Side Effects & Interactions

Potential Side Effects
  • Nausea and GI upset, especially on an empty stomach
  • Headache in caffeine-sensitive individuals
  • Liver toxicity risk at very high doses (rare but documented)
  • Mild insomnia if taken late in the day
Drug & Nutrient Interactions
  • Blood thinners (EGCG has mild antiplatelet properties)
  • Iron supplements (EGCG reduces non-heme iron absorption, take separately)
  • Stimulant medications (additive effects from caffeine content)
  • Statins (theoretical interaction via CYP enzyme pathways)

Who Should Consider It

Good candidates

  • Individuals seeking a mild, stimulant-gentle thermogenic
  • People combining with caffeine for synergistic fat oxidation
  • Those interested in antioxidant benefits alongside weight management

Use caution or avoid

  • Individuals with liver conditions
  • Those with iron deficiency anemia (take separately from iron)
  • Pregnant or breastfeeding individuals
Medical Disclaimer

This information is for educational purposes only. It does not constitute medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you have health conditions or take medications.

Third-Party Testing

This supplement has products available with independent quality verification.

USP Verified
Informed Sport
Evidence Breakdown
Overall Score7/10
Popularity8/10

Evidence Level

Moderate

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