Green Tea Extract (GTE) is derived from the Camellia sinensis plant and is rich in polyphenols, particularly epigallocatechin gallate (EGCG). In the context of endometriosis, GTE is being investigated for its anti-inflammatory, antioxidant, and anti-angiogenic properties, which may help mitigate disease progression and symptoms.

Quick answer

What it is: Green Tea Extract (GTE) is derived from the Camellia sinensis plant and is rich in polyphenols, particularly epigallocatechin gallate (EGCG).

May support:Endometriosis, Parkinson's Disease, Obesity, Rheumatoid Arthritis, Beauty & Anti-Aging

Evidence:Evidence · Grade C

Evidence Summary

Evidence · Grade C

The current evidence grade is based on established general knowledge regarding green tea and its components, as no specific PubMed studies were provided for this request. Claims are conservative and reflect potential benefits observed in broader research on green tea and its constituents, often from in vitro or animal studies, or epidemiological observations.

Last reviewed · Jun 2026

Have you tried Green Tea Extract?

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What did you try it for?

Your experience for Endometriosis:

Related conditions

Endometriosis Parkinson's Disease Obesity Rheumatoid Arthritis Beauty & Anti-Aging

Special diets that may apply

Dietary protocols studied for the conditions this remedy is associated with.

Anti-Inflammatory Diet

A whole-foods pattern designed to lower chronic, low-grade inflammation by emphasizing omega-3s, polyphenols, fiber, and minimizing ultra-processed foods, sugar, and seed oils.

Protocol· Harvard Medical School

For Beauty & Anti-Aging

The anti-inflammatory diet is not a single protocol but a synthesis of the patterns most consistently linked to lower inflammatory markers (CRP, IL-6, TNF-alpha) in human studies — Mediterranean-style eating, oily fish, abundant polyphenols, and low intake of ultra-processed foods, refined sugar, industrial seed oils, and excessive alcohol.

Foods to emphasize

Fatty fish 2–3x/week (salmon, sardines, mackerel, herring)
Extra-virgin olive oil
Berries, cherries, and other deeply colored fruit
Dark leafy greens and cruciferous vegetables
Turmeric, ginger, and culinary herbs
Green tea
Nuts (especially walnuts) and seeds (flax, chia)
Legumes and whole grains
Dark chocolate (≥70% cocoa) in moderation

Foods to avoid

Sugar-sweetened beverages and refined sugar
Ultra-processed snacks and ready meals
Industrial seed oils used at high heat (soybean, corn, sunflower, cottonseed)
Processed and cured meats
Refined flour products
Excess alcohol

Key principles

Cook with olive oil, finish with extra-virgin olive oil
Aim for 25–35 g of fiber per day from whole foods
Eat the rainbow — color diversity ~ polyphenol diversity
Limit added sugar to <25 g/day

Typical duration: A long-term eating pattern.

Why it may help

Beauty & Anti-Aging: Polyphenol- and omega-3-rich diets are linked with better skin elasticity, hydration, and reduced photoaging markers.

Safe and flexible. Can be combined with Mediterranean, vegetarian, or plant-forward patterns.

Vegetarian Diet

A plant-based eating pattern that excludes meat, poultry, and fish but typically allows eggs and/or dairy.

Protocol· Academy of Nutrition and Dietetics

For Beauty & Anti-Aging

Vegetarian diets range from lacto-ovo (includes eggs and dairy) to lacto (dairy only) and ovo (eggs only). Done well, they are associated with lower rates of cardiovascular disease, type 2 diabetes, and some cancers. Done poorly, they can be high in refined grains and low in key nutrients (B12, iron, omega-3s, zinc).

Foods to emphasize

Legumes (lentils, chickpeas, beans, tofu, tempeh)
Whole grains (oats, quinoa, brown rice, whole wheat)
Vegetables and fruit, daily and varied
Nuts and seeds (almonds, walnuts, chia, flax, hemp)
Eggs and/or dairy if included
Fortified foods or supplements for B12

Foods to avoid

Highly processed meat substitutes (occasional only)
Sugar-sweetened beverages
Refined grains as the bulk of meals
Excessive cheese as the primary protein source

Key principles

Plan for protein at every meal (legumes, tofu, tempeh, eggs, dairy)
Pair iron-rich plants with vitamin C to boost absorption
Plan a reliable B12 source — fortified foods or a supplement
Include omega-3 ALA from flax, chia, walnuts; consider an algae-based EPA/DHA supplement

Typical duration: A long-term eating pattern.

Why it may help

Beauty & Anti-Aging: High intake of plant antioxidants is linked with better skin antioxidant capacity and lower oxidative stress markers in observational studies.

Nutritional adequacy depends on planning, not just food choice. A registered dietitian can help avoid common gaps.

Linked nutrient deficiencies

Vitamin and mineral deficiencies commonly associated with the conditions this remedy may support.

Vitamin C

Water-soluble vitamin

Antioxidant required for collagen synthesis, immune function, and iron absorption.

Protocol· NIH Office of Dietary Supplements

Linked to Beauty & Anti-Aging

Deficiency is linked to frequent infections, poor wound healing, easy bruising, and accelerated skin aging.

Common symptoms

Frequent colds
Bleeding gums
Easy bruising
Slow wound healing
Dry, rough skin

Food sources

Bell peppers
Citrus fruits
Strawberries
Kiwi
Broccoli
Camu camu (concentrated)

Lab markers to discuss

Plasma vitamin C
Leukocyte ascorbate (research only)

Reference intake: 75–90 mg/day RDA; 500–2,000 mg/day commonly used for immune support.

Supplementation notes: Split high doses through the day. Liposomal forms improve absorption at higher intakes.

Why it matters here

Beauty & Anti-Aging: Cofactor for collagen synthesis; deficiency accelerates skin aging.

Vitamin A (Retinol)

Fat-soluble vitamin

Required for epithelial integrity, immune defense, vision, and skin renewal.

Protocol· NIH Office of Dietary Supplements

Linked to Beauty & Anti-Aging

Low vitamin A impairs mucosal immunity, gut barrier integrity, and skin cell turnover.

Common symptoms

Dry eyes, night blindness
Dry or rough skin
Frequent respiratory infections
Slow wound healing

Food sources

Liver
Egg yolks
Cod liver oil
Butter from grass-fed cows
Orange/yellow produce (as beta-carotene)

Lab markers to discuss

Serum retinol
Retinol-binding protein

Reference intake: 700–900 mcg RAE/day; avoid >3,000 mcg/day preformed retinol in pregnancy.

Supplementation notes: Beta-carotene conversion is poor in some genotypes — preformed retinol may be needed.

Why it matters here

Beauty & Anti-Aging: Drives epithelial turnover and skin renewal.

Omega-3 Fatty Acids (EPA/DHA)

Essential fatty acid

Anti-inflammatory lipids critical for brain, joint, and skin health.

Protocol· Cleveland Clinic — Omega-3 Fatty Acids

Linked to Beauty & Anti-Aging

Low EPA/DHA status correlates with depression, anxiety, dry skin, joint pain, and autoimmune flare risk.

Common symptoms

Dry skin or eczema
Joint stiffness
Low mood
Dry eyes
Poor concentration

Food sources

Wild salmon
Sardines, anchovies, mackerel
Cod liver oil
Algae oil (vegan)
Walnuts and flax (ALA only)

Lab markers to discuss

Omega-3 Index (target 8–12% of RBC membrane fatty acids)

Reference intake: 250–500 mg combined EPA+DHA/day baseline; 1–3 g/day therapeutic.

Supplementation notes: Choose IFOS-certified or molecularly distilled fish oils to minimize heavy-metal exposure.

Why it matters here

Beauty & Anti-Aging: Maintains skin barrier and reduces inflammatory aging.

Zinc

Trace mineral

Required for immune function, wound healing, skin integrity, and thyroid hormone synthesis.

Protocol· NIH Office of Dietary Supplements

Linked to Beauty & Anti-Aging

Low zinc is linked to recurrent infections, acne, slow wound healing, leaky gut, and impaired taste/smell. Often deficient in vegetarians and those with gut malabsorption.

Common symptoms

Frequent colds/infections
Acne or slow-healing skin
Loss of taste or smell
Hair loss
White spots on nails

Food sources

Oysters
Beef and lamb
Pumpkin seeds
Cashews
Lentils and chickpeas

Lab markers to discuss

Plasma or serum zinc
Zinc/copper ratio

Reference intake: 8–11 mg/day RDA.

Supplementation notes: Take away from iron and calcium. Long-term high-dose zinc depletes copper — pair with ~1 mg copper if dosing >30 mg/day.

Why it matters here

Beauty & Anti-Aging: Required for wound healing and collagen formation.

Vitamin D

Fat-soluble vitamin

Hormone-like vitamin central to immune function, mood, bone, and thyroid health.

Protocol· NIH Office of Dietary Supplements

Linked to Beauty & Anti-Aging

Low vitamin D status is one of the most widespread deficiencies globally and has been linked to autoimmune disease activity (Hashimoto's, MS), mood disorders, recurrent infections, and poor skin barrier function.

Common symptoms

Fatigue
Low mood
Frequent infections
Bone or muscle aches
Hair thinning

Food sources

Fatty fish (salmon, sardines)
Egg yolks
Cod liver oil
UV-exposed mushrooms
Fortified dairy

Lab markers to discuss

25-hydroxyvitamin D (target 40–60 ng/mL per most functional ranges)

Reference intake: Adults 600–800 IU/day RDA; functional medicine often targets 2,000–5,000 IU/day with monitoring.

Supplementation notes: Take with a fat-containing meal. Pair with vitamin K2 (MK-7) when supplementing higher doses long-term.

Why it matters here

Beauty & Anti-Aging: Influences skin barrier function and pigmentation pathways.

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What people say about Green Tea Extract

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Why It Works

EGCG in GTE has been shown to inhibit the proliferation and migration of endometrial cells by modulating signaling pathways involved in cell growth and survival. It may also reduce inflammation by decreasing pro-inflammatory cytokines and inhibit angiogenesis, a process crucial for the growth of endometriotic lesions, by suppressing factors like VEGF.

How it works in more detail

Green tea extract's primary active compounds, catechins (especially EGCG), exert antioxidant effects by scavenging reactive oxygen species and chelating metal ions. EGCG may also modulate intracellular signaling pathways, including those involving NF-κB, AP-1, and MAPK, which are implicated in inflammation and cell proliferation. Furthermore, EGCG has been suggested to influence lipid metabolism by inhibiting enzymes such as fatty acid synthase and acetyl-CoA carboxylase, and to affect thermogenesis through sympathetic nervous system activation, potentially by inhibiting catechol-O-methyltransferase (COMT), which degrades norepinephrine.

How to use

Always consult a qualified clinician.

Editorial guidance

Suggested dosage

Animal studies and some human pilot studies have used doses of EGCG ranging from 200 mg to 800 mg daily, standardized to contain a high percentage of EGCG.

Research dosage range

Research dosages for green tea extract or its isolated catechins (like EGCG) have varied significantly, typically ranging from 100 mg to 1200 mg of EGCG per day, often divided into multiple doses.

Typical forms

capsule, tablet, powder

Quality markers

Look for products standardized to a specific percentage of catechins or EGCG. Choose reputable brands that provide third-party testing for purity and absence of contaminants. Opt for decaffeinated versions if caffeine sensitivity is a concern.

Medication interactions

Anticoagulants (e.g., Warfarin)
Statins
Beta-blockers
Chemotherapy drugs
Stimulants
Iron supplements

Avoid if

Pregnant or breastfeeding
Liver disease
Iron deficiency anemia
Bleeding disorders
High blood pressure
Anxiety disorders (due to caffeine)

Community tips

No community tips yet — be the first to share what worked for you.

Suggested dosage

Animal studies and some human pilot studies have used doses of EGCG ranging from 200 mg to 800 mg daily, standardized to contain a high percentage of EGCG.

General guidance — discuss specifics with a clinician.

Active medicinal compounds

Epigallocatechin gallate (EGCG), Epigallocatechin (EGC), Epicatechin gallate (ECG), Epicatechin (EC), Caffeine (in non-decaffeinated forms).

Traditional use

Green tea has been consumed for thousands of years in Asian cultures, particularly in China and Japan, where it is revered for its cultural significance and perceived health benefits. Traditional uses include aiding digestion, promoting mental clarity, and as a general tonic for well-being. It was also used in traditional medicine systems for various ailments, though not typically in a concentrated extract form.

Safety

Safety warnings

Green Tea Extract is generally considered safe. However, high doses, especially on an empty stomach, can lead to liver toxicity in susceptible individuals. Mild side effects may include nausea, stomach upset, and dizziness.

Avoid if

Pregnant or breastfeeding
Liver disease
Iron deficiency anemia
Bleeding disorders
High blood pressure
Anxiety disorders (due to caffeine)

Medication interactions

Anticoagulants (e.g., Warfarin)
Statins
Beta-blockers
Chemotherapy drugs
Stimulants
Iron supplements

Reported side effects

Nausea
Stomach upset
Headache
Dizziness
Insomnia (due to caffeine)
Liver enzyme elevation

General guidance — discuss specifics with a clinician.

Evidence ecosystem

Scientific literature, clinical guidance, government sources, ongoing research, traditional use, and lived experience — grouped by source type and quality.

Overall grade (C)

The current evidence grade is based on established general knowledge regarding green tea and its components, as no specific PubMed studies were provided for this request. Claims are conservative and reflect potential benefits observed in broader research on green tea and its constituents, often from in vitro or animal studies, or epidemiological observations.

Filter by source type

Systematic Reviews(1)

Structured reviews of the full body of evidence (incl. Cochrane).

Very High Quality

Polyphenol Intervention Ameliorates Non-Alcoholic Fatty Liver Disease: An Updated Comprehensive Systematic Review.
Ranneh Y, Bedir AS, Abu-Elsaoud AM, Al Raish S · Nutrients · 2024
Non-alcoholic fatty liver disease (NAFLD) has recently emerged as a challenging metabolic disorder with a strong emphasis on its prevention and management. Polyphenols, a group of naturally occurring plant compounds, have been associated with a decreased risk of various metabolic disorders related to NAFLD. The current systematic review aims to critically assess evidence about the ameliorative effect of polyphenol supplementation on NAFLD patients. A PRISMA systematic search appraisal was conducted in PubMed, Scopus, Web of Science Core Collection, and all relevant studies published prior to April 2024 and met the inclusion criteria were included. Twenty-nine randomized clinical trials (RCTs) comprised 1840 NAFLD patients. The studies primarily examined eleven phenolic compounds, including turmeric, curcumin, resveratrol, genistein, catechin, green tea extract, hesperidin, and silymarin. Turmeric and curcumin decreased liver enzymes, inflammatory cytokines, lipid profile, insulin resis
Systematic ReviewPubMedVery High Quality

Clinical Trial Registries(1)

Registered ongoing or completed trials (ClinicalTrials.gov).

Moderate Quality

Effect of Over-the-counter Dietary Supplements on Kidney Stone Risk
n=45 · NCT02404701 · COMPLETED · COMPLETED
The purpose of this study is to ascertain whether certain supplements promote excessive urinary oxalate excretion and increase the risk for calcium oxalate kidney stones. Supplements that enhance urinary oxalate excretion, as a result of their oxalate concentration or from some other mechanism (e.g., providing substrate for oxalate biosynthesis) will be identified by the investigators.
Clinical TrialClinicalTrials.govModerate Quality

Limitations: Without specific PubMed studies, the evidence base for green tea extract's efficacy in treating specific ailments is limited to general knowledge and broader research on green tea. There is a lack of direct clinical trial data to support specific health claims for the extract form, particularly regarding optimal dosages, long-term safety, and effectiveness in human populations for the listed conditions.

Green Tea Extract

Quick answer

Evidence Summary

Have you tried Green Tea Extract?

Commonly Combined With

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What people say about Green Tea Extract

Latest news on Green Tea Extract

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Why It Works

How it works in more detail

How to use

Suggested dosage

Active medicinal compounds

Traditional use

Safety

Evidence ecosystem

Systematic Reviews(1)

Clinical Trial Registries(1)