EGCG, green tea's main active compound, has small, mostly metabolic effects: modest drops in total cholesterol and its artery-damaging fraction, lower blood pressure where pressure is already raised, and slight weight and fat loss that depends on caffeine acting alongside it. Concentrated capsules, not brewed tea, carry a liver-injury signal, largely avoidable through dose, timing and taking with food. (Full Review)

Protocol

Standard practitioner dose

200–400 mg EGCG daily

From a standardized green tea extract, taken with food; trial doses range from 200 mg to 800 mg daily.

Best time of day

Morning or early afternoon with a meal

Caffeinated extracts taken after mid-afternoon interfere with sleep onset; the thermogenic effect is largest before daytime activity.

Single versus split dosing

Split doses above 250 mg

Two administrations twelve hours apart, lowering peak concentration for hepatic safety while keeping total daily exposure constant.

Time to effect

Lipids and blood pressure

8–12 weeks

Requires daily intake.

Body composition

Roughly 12 weeks

Change is measurable only after that point.

Thermogenic and glucose effects

Within hours

Appear after a single dose.

Benefits

High: Reduction in total and LDL cholesterol; reduction in blood pressure; reduction in body weight and body fat; reduced incidence of influenza and upper-respiratory infection; reduced recurrence of colorectal adenoma

Medium: Improvement in glycemic control; lower cardiovascular mortality with habitual intake; reduction in uterine fibroid volume and symptom burden; improvement in liver enzymes in fatty liver disease; reduced ultraviolet-induced skin erythema

Low: Improvement in endothelial function; acute effects on calmness and cognition; chemoprevention in high-grade prostatic intraepithelial neoplasia

Speculative: Extension of lifespan and healthspan; clearance of senescent cells and restoration of autophagy; neuroprotection in Alzheimer's and Parkinson's models

Contraindications

Active liver disease, chronic hepatitis B or C, cirrhosis (Child-Pugh Class B or C), or prior drug-induced liver injury

Baseline alanine aminotransferase above twice the upper limit of normal

Treatment with bortezomib, carfilzomib or ixazomib

Pregnancy and breastfeeding

Children and adolescents under 18

Iron-deficiency anemia with serum ferritin below 30 ng/mL (until repletion complete)

Key Interactions

Beta-blockers transported by OATP1A2 (nadolol, atenolol, celiprolol)

Statins (simvastatin, atorvastatin, rosuvastatin)

Antihistamines and other OATP substrates (fexofenadine, aliskiren)

Warfarin

Methotrexate

Over-the-counter acetaminophen

Over-the-counter stimulants and decongestants (pseudoephedrine, caffeine tablets)

Iron supplements

Additive supplement interactions (berberine, bergamot, red yeast rice, plant sterols, beetroot, garlic, hibiscus)

Hepatotoxic supplement interactions (ashwagandha, kava, garcinia, high-dose niacin)

Other intervention interactions (prolonged fasting, very low-carbohydrate protocols)

Risk & Side Effects

High: Hepatocellular liver injury; gastrointestinal intolerance

Medium: Reduced absorption of co-administered oral drugs; impaired non-heme iron absorption; lowering of circulating folate; stimulant effects from co-formulated caffeine

Low: Blunting of training adaptations

Speculative: Antagonism of boronic-acid proteasome inhibitors; pro-oxidant DNA damage at supraphysiologic concentrations

Monitoring

Marker	Target	Why
Alanine aminotransferase	10–26 U/L (men), 10–19 U/L (women)	Earliest and most sensitive signal of hepatocellular injury
Aspartate aminotransferase	10–26 U/L	Confirms a hepatocellular pattern alongside alanine aminotransferase
Alkaline phosphatase	40–90 U/L	Distinguishes bile-duct from liver-cell injury patterns
Gamma-glutamyl transferase	Under 20 U/L (men), under 15 U/L (women)	Sensitive marker of hepatic oxidative load
Total bilirubin	0.3–1.0 mg/dL	Rising bilirubin with raised liver enzymes marks clinically significant injury
LDL cholesterol	Under 100 mg/dL, or under 70 mg/dL at elevated cardiovascular risk	Primary efficacy endpoint for the best-supported benefit
Total cholesterol	160–200 mg/dL	The marker with the largest pooled effect size in the trial literature
HbA1c	4.8–5.4%	Tracks whether the small glycemic effect is materializing
Serum ferritin	50–150 ng/mL (men), 40–120 ng/mL (women)	Detects iron depletion from catechin chelation
Serum folate	Above 10 ng/mL	Detects the dihydrofolate reductase inhibition effect
Seated blood pressure	Under 120/80 mm Hg	Second best-supported efficacy endpoint
Body weight and waist circumference	Waist under 94 cm (men), under 80 cm (women)	Tracks the thermogenic and body-composition effect

Cadence: Liver panel at baseline, repeated at 8–12 weeks, then every 6 months, with an immediate unscheduled check if any hepatitis symptom appears. Lipids, glucose and blood pressure are rechecked at 12 weeks, then annually. Ferritin repeats at 6 months where baseline stores were low-normal.

Qualitative Assessment

Energy level and perceived exertion during habitual training sessions
Sleep onset latency and night-waking frequency, particularly with caffeinated preparations
Appetite and inter-meal hunger, the subjective correlate of the thermogenic effect
Digestive comfort — nausea, reflux and stool consistency in the first two weeks
Right upper abdominal discomfort, unusual fatigue, dark urine or yellowing of the eyes, any of which warrants immediate testing
Subjective calmness and mental clarity in the two hours after a dose

EGCG for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment