Green Tea Extract

What it is

Green Tea Extract is prepared from the unfermented leaves of Camellia sinensis. It is standardized to contain elevated concentrations of bioactive green tea catechins, particularly epigallocatechin-3-gallate (EGCG), which accounts for over 50% of the polyphenol content. Formulated as a water-soluble or dry standardized powder in dietary supplements, green tea extract provides concentrated polyphenol firepower to support resting energy expenditure, lipid metabolism, cellular defense, and metabolic health.

Also known as: Camellia sinensis, EGCG, Epigallocatechin Gallate

Key benefits

• Stimulates resting thermogenesis and fat oxidation by inhibiting catechol-O-methyltransferase enzymatic breakdown.
• Protects cellular lipids, proteins, and DNA from oxidative degradation through high-potency EGCG radical scavenging.
• Supports postprandial metabolic homeostasis and healthy blood lipid and cholesterol profiles.
• Acts as a selective prebiotic agent to support beneficial intestinal bacterial colonization.

Amplified by probiotics

Green tea catechins and gut probiotics exhibit a mutually beneficial, bi-directional relationship in the gastrointestinal tract. Intestinal bacterial enzymes hydrolyze EGCG and related flavan-3-ols into bioavailable valerolactones and small phenolic acids, which enter systemic circulation and display enhanced tissue distribution. Unabsorbed EGCG selectively modulates the gut microbiome, inhibiting pathogenic Clostridium species while promoting the proliferation of beneficial Bifidobacteria and Lactobacilli strains. In turn, microencapsulated live probiotics strengthen the intestinal mucosal barrier and generate short-chain fatty acids like butyrate, which mitigate mucosal oxidative stress and optimize polyphenol absorption channels. This synergistic loop enhances metabolic thermogenesis, reduces low-grade gut inflammation, and maximizes systemic catechin bioactivity.

Typical dose

250–500 mg/day

The evidence

Comprehensive meta-analyses of randomized controlled trials demonstrate that green tea extract standardized for EGCG significantly increases energy expenditure, promotes modest fat loss, and improves waist circumference measures. Clinical evidence confirms its potent systemic antioxidant effects and positive modulation of cardiometabolic markers. Research further highlights EGCG's capacity to favorably reshape human gut microbiota composition.

1. Hursel R, et al. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obes (Lond). 2009;33(9):956-961. PubMed ↗
2. Jurgens TM, et al. Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database Syst Rev. 2012;12(12):CD008650. PubMed ↗
3. Chen IJ, et al. Therapeutic effect of high-dose green tea extract on weight reduction: A randomized, double-blind, placebo-controlled clinical trial. Clin Nutr. 2016;35(3):592-599. PubMed ↗

Safety & who should check first

Standardized green tea extract is safe when consumed at recommended levels; daily EGCG intake should remain under 800 mg to prevent rare liver enzyme elevations. Take with food, and exercise caution if sensitive to caffeine or taking iron supplements.