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Green tea extract

Epigallocatechin Gallate (EGCG)
Also known as: EGCG, Green tea extract, Camellia sinensis
Food-Derived

Content by: OpenSupplement Editorial Team  |  Medical review: pending  |  Last updated: April 13, 2026

Evidence ★★★☆☆3/5
Best for
Metabolic syndromeCognition
Typical dose250-500 mg EGCG/day with food
SafetyWorth noting
Onset2–4 weeks
Cost$8-15/mo
References3 studies cited

TL;DR

  • Concentrated antioxidant polyphenol from green tea leaves

  • Moderate evidence for boosting metabolism and fat oxidation

  • Moderate-to-low evidence for cognitive protection and liver health

  • Potential for liver toxicity at very high doses on an empty stomach

  • Inexpensive: ~$8-15/month

  • Best for: Metabolic support, general antioxidant defense

What it is

EGCG (Epigallocatechin gallate) is the most abundant and potent catechin in green tea. It is a powerful antioxidant that protects cells from oxidative damage. Mechanistically, EGCG inhibits an enzyme that breaks down norepinephrine, the hormone that tells fat cells to break down fat.

While drinking green tea is great, supplements provide a concentrated dose of EGCG (often equivalent to 5-10 cups of tea) to reach 'therapeutic' levels for metabolic or neuroprotective effects.

What the research says

Metabolic syndromeRelevance: Moderate
Evidence
3/5
Onset speed
3/5
Typical dose: 250-500 mg EGCG/day with food

EGCG is a popular but modest weight loss aid. Fat Oxidation. Clinical trials show that green tea extract can increase 24-hour energy expenditure and fat oxidation (burning). Weight Loss. A 2009 meta-analysis showed that green tea catechins significantly decreased body weight and helped maintain weight loss. Note. The effect is small—usually a few pounds over several months—and works best when combined with light caffeine. [1][2]

Cognitive declineRelevance: Low
Evidence
2.5/5
Onset speed
2/5
Typical dose: 250-500 mg EGCG/day

EGCG is a promising neuroprotective agent. The Amyloid Link. Lab studies show EGCG can prevent the misfolding of proteins associated with Alzheimer's. Evidence. Population studies show green tea drinkers have lower rates of cognitive decline, but clinical trials are still in early phases. It is best viewed as a 'brain healthy' habit rather than a treatment for memory loss.

Liver diseaseRelevance: Low
Evidence
1.5/5
Onset speed
1/5
Typical dose: Use with caution

This is a double-edged sword. Potential Benefit. In low doses, EGCG may reduce liver fat and inflammation. Risk. However, high doses of green tea extract (especially on an empty stomach) have been linked to rare but serious liver injury. Recommendation. Do not exceed 800mg of EGCG daily, and always take it with food. [3]

DISCLAIMER: The information on this page is for educational purposes only and has not been evaluated by the Food and Drug Administration. This content is not intended to diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare professional before using any dietary supplement, especially if you are pregnant, nursing, taking medication, or have a medical condition.

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Green tea extract on Amazon

$8-15/mo (estimated)
See on Amazon →

Safety

Safe for most at standard doses. However, the 'concentrated' nature of extracts can be hard on the liver for some individuals. Crucial: Never take high-dose EGCG on an empty stomach. If you have any history of liver disease, consult a doctor first.

Interactions

  • Stimulants: May increase heart rate or jitteriness when combined with other caffeine sources.
  • Blood Thinners: May have a mild anti-clotting effect.
  • Nadolol: Green tea can significantly reduce the absorption of this blood pressure medication.

Dosing

Standard Dose: 200-500 mg of EGCG daily. Timing: Take with food. Form: Look for 'decaffeinated' if you are sensitive to stimulants.

Cost

Affordable. $8-15 per month.

The bottom line

Green tea extract is a great 'foundational' antioxidant. It's not a magic weight loss pill, but it provides broad cellular protection and a small metabolic nudge.

References

  1. Meta-analysisMetabolic syndromePubMed →
  2. Meta-analysisMetabolic syndromePubMed →
  3. ReviewLiver diseasePubMed →

Sources for this page include published meta-analyses, systematic reviews, and NIH dietary supplement fact sheets. All claims reflect the evidence as of early 2026.

This is not medical advice. Consult your healthcare provider before starting any supplement, especially if you take medications.