Comparison
EGCG vs Metformin
Side-by-side of EGCG and Metformin. Every row below is pulled from the compound schema and will update as our data grows. For deeper reads, follow through to each compound page.
EGCG
EGCG supplement guide: 300-600 mg/day green tea catechin for fat loss and cardiovascular markers. Hepatotoxicity risk above 800 mg/day fasted.
Metformin
Metformin for longevity: biguanide mechanism of action, TAME trial status, anti-aging dosage, weight loss data, life extension evidence in non-diabetics.
Effects at a glance
EGCG
- •Modest fat loss (~1.3 kg over 12 weeks) when combined with caffeine and caloric deficit
- •Small reductions in LDL cholesterol (3-6 mg/dL) and systolic blood pressure (2-3 mmHg)
- •EFSA flags hepatotoxicity risk above 800 mg/day, particularly when taken fasted
- •Bioavailability is 0.1-1.0%; gut microbiome variation drives population-variable response
- •Green tea extract typically combines EGCG with caffeine and L-theanine for additive effects
- •Reduces non-heme iron absorption when co-administered with meals
Metformin
- •Reduces HbA1c by ~1.0 to 1.5 percentage points in type 2 diabetes; first-line agent in major guidelines
- •DPP trial: 31% reduction in T2DM incidence in adults with prediabetes over 2.8 years
- •Suppresses hepatic gluconeogenesis via AMPK activation and complex I inhibition
- •Long-term use depletes B12; annual monitoring recommended after year 2
- •Lifespan extension in non-diabetic humans is not established; TAME trial pending
- •MASTERS trial reported blunted resistance-training hypertrophy in older adults
Side-by-side
| Attribute | EGCG | Metformin |
|---|---|---|
| Category | natural | pharmaceutical |
| Also known as | epigallocatechin gallate, green tea extract | Glucophage, Fortamet, Glumetza, dimethylbiguanide |
| Half-life (hr) ↗ | 3 | 6 |
| Typical dose (mg) ↗ | 400 | 1500 |
| Dosing frequency | 1 to 2 times daily with food | 1 to 3 times daily with meals; XR once daily |
| Routes | oral | oral |
| Onset (hr) | 1.5 | 1 |
| Peak (hr) | 2 | 2.5 |
| Molecular weight | 458.37 | 129.16 |
| Molecular formula | C22H18O11 | C4H11N5 |
| Mechanism | Inhibits catechol-O-methyltransferase (COMT) to prolong norepinephrine signaling; activates AMPK; scavenges reactive oxygen species via gallate ester; modulates gut microbiome and pancreatic lipase activity. | Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition. |
| Legal status | Dietary supplement; warning labels required above 800 mg/day in some EU jurisdictions | Prescription only (FDA approved for type 2 diabetes 1994) |
| WADA status | allowed | allowed |
| DEA / Rx | Not scheduled | Rx only (not a controlled substance) |
| Pregnancy | Avoid high-dose extracts; moderate green tea consumption appears acceptable | Category B; used in gestational diabetes and PCOS per current guidance |
| CAS | 989-51-5 | 657-24-9 |
| PubChem CID | 65064 | 4091 |
| Wikidata | Q307091 | Q19484 |
Safety profile
EGCG
Common side effects
- nausea
- abdominal discomfort
- diarrhea
- jitteriness (with caffeine)
- sleep disruption (with caffeine)
Contraindications
- pregnancy at high-dose extracts
- active liver disease
- iron deficiency anemia (separate dosing)
Interactions
- iron supplements: reduces non-heme iron absorption; separate by 2 to 3 hours(moderate)
- anticoagulants: additive effects at high catechin doses(minor)
- beta-blockers (nadolol): reduced absorption when taken simultaneously(moderate)
- hepatotoxic supplements (high-dose niacin, kava): theoretical additive hepatotoxicity at high EGCG doses(moderate)
- stimulants and caffeine: additive thermogenic and cardiovascular effects(minor)
Metformin
Common side effects
- nausea
- diarrhea
- abdominal discomfort
- metallic taste
- decreased appetite
- B12 depletion (long-term)
Contraindications
- eGFR below 30 mL/min/1.73m2
- acute or chronic metabolic acidosis
- severe hepatic impairment
- acute heart failure
- iodinated contrast within 48 hours
Interactions
- iodinated contrast media: renal injury risk; hold 48 hours peri-imaging(major)
- alcohol (heavy use): elevated lactic acidosis risk(major)
- cimetidine: raises metformin plasma levels via OCT2 inhibition(moderate)
- insulin and sulfonylureas: additive hypoglycemia risk in combination(moderate)
- dolutegravir: raises metformin exposure via OCT2(moderate)
Which Should You Take?
EGCG comes out ahead for most readers on the criteria we weight: 3 catalogued goals, OTC dietary supplement, oral dosing, with a Tier-B outcome catalogued. Metformin is the right call when one of the conditionals below applies.
- → If your priority is cardiovascular health, pick EGCG.
- → If your priority is metabolic health and glucose control, pick EGCG.
- → If your priority is healthspan extension, pick EGCG.
Edge case: If you want to avoid prescription-only, EGCG is the more accessible choice.
Default choice: EGCG. Lower friction to source, and broader goal coverage. Reach for Metformin only if your priority sits squarely in the goals it owns above.
This verdict is generated from each compound's schema (goals, legal status, evidence outcomes, dosing route). It updates automatically as our compound data evolves; the deeper read sits on each individual compound page.
Common questions
What is the difference between EGCG and Metformin?
EGCG and Metformin differ in category (natural vs pharmaceutical), mechanism, and typical dosing. See the side-by-side table for full details.
Which has a longer half-life, EGCG or Metformin?
EGCG half-life is 3 hours; Metformin half-life is 6 hours.
Can you stack EGCG with Metformin?
Stack compatibility depends on mechanism overlap, legal status, and individual response. Check each compound page for specific interactions and contraindications before combining.
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