Natural antioxidant compounds concentrated in green tea. Human evidence shows real but modest benefits: small reductions in cholesterol and blood pressure, better blood-vessel function, and a minor caffeine-dependent weight effect. Higher intake is linked to lower death rates, though unproven. Ordinary tea is very safe; concentrated high-dose extracts can injure the liver. (Full Review)

Protocol

Beverage

3–5 cups/day

Whole green tea, ~200–400 mg catechins daily; best-tolerated form

Standardized extract

250–500 mg/day

Catechins for lipid, blood-pressure, or metabolic goals; keep EGCG below 800 mg/day

Timing

With meals, split

Two doses (e.g. breakfast and lunch); caffeinated forms morning and midday

Time to effect

Lipids & blood pressure

4–12 weeks

Cholesterol and blood-pressure changes with consistent intake

Weight

~12 weeks

Modest weight and fat effects

Alertness

Within an hour

Acute effect, largely from caffeine and L-Theanine

Benefits

High: Lower LDL and total cholesterol; reduced blood pressure

Medium: Modest body weight and fat loss; lower cardiovascular and all-cause mortality; improved glycemic control

Low: Prostate cancer chemoprevention; improved liver enzymes in fatty liver; skin photoprotection; cognitive and mood effects

Speculative: Longevity and healthspan extension; neuroprotection in Parkinson's and Alzheimer's disease

Contraindications

Bortezomib therapy

Liver disease or prior drug-induced liver injury

Pregnancy and breastfeeding (concentrated extracts)

Iron-deficiency anemia

Children

Severe cardiovascular disease, high-caffeine forms (heart attack within 90 days, unstable arrhythmia, NYHA Class III–IV)

Key Interactions

Beta-blockers (e.g. nadolol)

Warfarin

Statins (e.g. simvastatin)

Acetaminophen

Stimulant medications and supplements (e.g. synephrine, caffeine)

Iron supplements

Risk & Side Effects

High: Liver injury from high-dose extracts

Medium: Gastrointestinal distress; non-heme iron malabsorption

Low: Caffeine-related effects; reduced efficacy of bortezomib

Speculative: Bleeding risk and vitamin K interaction; kidney stones from oxalate

Monitoring

Marker	Target	Why
ALT	~10–25 U/L	Detects catechin-related liver stress
AST	~10–25 U/L	Complements ALT for liver injury
LDL cholesterol	<100 mg/dL	Primary lipid target catechins can lower
Total cholesterol	<180 mg/dL	Tracks overall lipid response
Ferritin	~50–100 ng/mL	Guards against catechin-driven iron depletion
Fasting glucose	70–90 mg/dL	Tracks glycemic response
HbA1c	<5.4%	Longer-term glycemic marker

Cadence: Baseline before high-dose extracts; liver enzymes at 4–8 weeks, then every 6–12 months if continued; cardiometabolic markers at 8–12 weeks.

Qualitative Assessment

Energy and daytime alertness
Sleep quality and time to fall asleep
Digestive comfort
Cognitive clarity and focus

Tea Catechins for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment