Berberine vs Metformin

Mechanism

Berberine activates AMP-activated protein kinase (AMPK), the master metabolic sensor, mimicking many effects of caloric restriction and exercise. It inhibits mitochondrial Complex I, increasing the AMP:ATP ratio which triggers AMPK. Downstream effects include enhanced GLUT4 translocation (glucose uptake), inhibition of HMG-CoA reductase (cholesterol synthesis), upregulation of LDL receptor expression, and suppression of PCSK9. It also modulates gut microbiome composition, increasing short-chain fatty acid-producing bacteria.

Standard Dosing

500mg 2-3x daily (1000-1500mg total)

Timing

With meals or immediately before meals (reduces postprandial glucose spike). Must be taken with food.

Cycle Duration

Cycle 8-12 weeks on, 4 weeks off (or continuous under practitioner supervision)

Side Effects

• GI cramping/diarrhea (dose-dependent)
• Constipation in some
• Abdominal distension
• Potential for hypoglycemia

Contraindications

• Pregnancy (uterotonic — may induce contractions)
• Lactation
• Concurrent use of multiple CYP3A4 metabolized drugs
• Severe liver disease
• Children under 12

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Mechanism

Metformin activates AMP-activated protein kinase (AMPK) via inhibition of mitochondrial Complex I, increasing the AMP/ATP ratio. AMPK activation triggers a cascade of metabolic effects: inhibition of hepatic gluconeogenesis, enhanced glucose uptake in skeletal muscle via GLUT4 translocation, and suppression of mTORC1 signaling. In the longevity context, metformin's mTOR inhibition mimics caloric restriction signaling, activating autophagy, reducing inflammatory cytokines (IL-6, TNF-a), decreasing insulin and IGF-1 signaling, and modulating the gut microbiome (increasing Akkermansia muciniphila). It also reduces AGE formation and mitochondrial ROS production.

Standard Dosing

Research indicates 500-1000 mg daily for longevity/anti-aging protocols. Standard diabetes dosing: 500-2550 mg daily.

Timing

Take with food (dinner) to minimize GI side effects. Extended-release formulation once daily with dinner. Immediate-release split into 2-3 doses with meals.

Cycle Duration

Ongoing for longevity applications. The TAME (Targeting Aging with Metformin) trial is designed to assess long-term geroprotective effects.

Side Effects

• GI distress: nausea, diarrhea, bloating, metallic taste (common initially, improves with XR formulation)
• Vitamin B12 deficiency (with chronic use — monitor annually)
• Lactic acidosis (rare but serious — primarily in renal impairment)
• Potential blunting of exercise-induced mitochondrial adaptations (debated)
• Weight loss (often considered a benefit)

Contraindications

• eGFR <30 mL/min/1.73m2 (contraindicated) or <45 (use with caution)
• Acute or chronic metabolic acidosis including lactic acidosis
• Heavy alcohol consumption
• Acute decompensated heart failure
• Hepatic failure
• Planned procedures with iodinated contrast dye

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