Green Tea Extract for Health & Longevity - Quick Reference Sheet
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Green Tea Extract for Health & Longevity

Created on 09/21/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 5 – Audit

A concentrated capsule form of green tea's plant compounds, at doses no tea drinking delivers. Pooled trials show small, consistent improvements in blood pressure, cholesterol, blood sugar and body fat, largest where readings start raised and negligible where they are already healthy. Against that: liver inflammation in a small share of users, and reduced absorption of many oral medications. (Full Review)

Protocol

Standard daily dose
400–500 mg epigallocatechin gallate daily
Typically 800–1,000 mg of a 50% standardised extract
Always with food
Capsules taken with a meal
Fasted dosing sharply raises catechin bioavailability and is the dosing pattern most associated with liver injury
Split versus single dose
Twice daily
Splitting with breakfast and the evening meal is standard; caffeinated preparations kept to before mid-afternoon
Time to effect
Blood pressure
4–12 weeks
Nothing meaningful is measurable in days
Lipids
4–12 weeks
Lipid changes appear on the same schedule as blood pressure
Body composition
12 weeks
Requires concurrent exercise

Benefits

Contraindications
  • Active or chronic liver disease, or ALT or AST above 2.5 times the upper reference limit
  • Prior liver injury attributed to a herbal or dietary supplement
  • Known HLA-B*35:01 genotype
  • Proteasome inhibitors (bortezomib, carfilzomib)
  • Tyrosine kinase inhibitors and antifibrotics during active therapy (erlotinib, nintedanib)
  • Pregnancy and breastfeeding
  • Iron-deficiency anaemia, or ferritin below 30 ng/mL until iron status is corrected
  • Heavy alcohol use (more than 14 standard drinks weekly)
    •
Key Interactions
  • Beta-blockers (nadolol, celiprolol, atenolol)
  • Statins (atorvastatin, rosuvastatin, but not simvastatin or fluvastatin)
  • Cardiac glycosides and antihistamines (digoxin, fexofenadine)
  • Angiotensin-converting enzyme inhibitors (lisinopril, enalapril)
  • Over-the-counter analgesics and antipyretics (paracetamol/acetaminophen, high-dose aspirin)
  • Over-the-counter decongestants and caffeine tablets (pseudoephedrine, caffeine), for caffeinated extracts only
  • Iron supplements (ferrous sulfate, ferrous bisglycinate)
  • Folic acid supplements
  • Other hepatically stressed supplements (Garcinia cambogia, kava, ashwagandha, high-dose niacin)
  • Additive-effect supplements (beetroot nitrate, hibiscus, magnesium, berberine)
  • Other interventions (calorie restriction, endurance training)
    •

Risk & Side Effects

  • High: Liver enzyme elevation and drug-induced liver injury; gastrointestinal intolerance; reduced absorption and efficacy of co-administered medications
  • Medium: Caffeine-related stimulant effects; reduced non-heme iron absorption
  • Low: Skin and subcutaneous reactions; rise in blood pressure in a minority of users
  • Speculative: Blunting of exercise-induced training adaptations
    •

Monitoring

Marker Target Why
ALT (alanine aminotransferase) Men < 30 U/L; women < 20 U/L Earliest signal of liver cell injury
AST (aspartate aminotransferase) < 25 U/L Confirms a liver source when ALT rises
Total bilirubin and ALP Bilirubin < 1.0 mg/dL; ALP 45–90 U/L Distinguishes injury with jaundice from a benign enzyme rise
Ferritin Men 50–150 ng/mL; women 40–120 ng/mL Decides whether iron chelation matters for this user
LDL cholesterol and ApoB LDL < 100 mg/dL; ApoB < 80 mg/dL Primary benefit endpoint for cardiovascular effect
HbA1c 5.0–5.4% Tracks the modest glycaemic effect over months
Blood pressure (home, 7-day average) < 120/80 mmHg The most responsive benefit endpoint

Cadence: Baseline panel before starting; liver enzymes repeated at 8–12 weeks, then every 6 months for as long as use continues; cardiometabolic panel at 12 weeks, then annually. Any new abdominal pain, dark urine or yellowing of skin or eyes triggers immediate testing regardless of schedule.

Qualitative Assessment

  • Upper-right abdominal discomfort or fullness, the earliest subjective correlate of liver strain
  • Urine colour, since darkening precedes visible jaundice
  • Sleep onset latency and night waking, which flag an unnoticed caffeine load
  • Daytime energy and exercise tolerance, which fall before other signs of liver trouble
  • Appetite and early satiety at meals, the only subjective correlate of the fat-oxidation effect
Not medical advice. Educational distillation of a single evidence review. Confirm any decision with a qualified clinician, especially in the presence of prescription drugs or chronic conditions.