Metformin dosage

Protocol

1. 1

   Measure the dose

   Typical Metformin dose is 1500 mg. Use a weight-based calculator for individual adjustments.

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2. 2

   Set the frequency

   Administer 1 to 3 times daily with meals; XR once daily. Half-life of 6 hours anchors the dosing interval.

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3. 3

   Cycle if needed

   No formal cycling; some longevity users skip on training days based on MASTERS hypertrophy data

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4. 4

   Monitor for side effects

   Watch for: nausea; diarrhea; abdominal discomfort; metallic taste. Stop or reduce dose if tolerability breaks down.

Why this dose

Suppresses hepatic gluconeogenesis primarily via AMPK activation and complex I inhibition; modestly improves peripheral insulin sensitivity and shifts gut microbiome composition.

The typical 1500 mg dose is the figure most commonly used in published protocols for Metformin. Treat the label as a starting point: body weight, training status, sleep, diet, and concurrent medications all shift the effective dose-response curve in real users.

How to administer

Metformin is administered via the oral route. Oral dosing is straightforward: take with water, with or without food unless specifically noted.

Onset of action runs around 1 hour after administration. Peak effect lands near 2.5 hours post-dose. Plan the administration window so that peak effect lines up with whatever outcome you are dosing for, whether that is training, sleep, or symptom coverage.

Half-life note: Terminal half-life 4 to 9 hours; renal elimination essentially unchanged; XR formulations extend effective duration

Cycling and tolerance

No formal cycling; some longevity users skip on training days based on MASTERS hypertrophy data

Effects to expect at typical dose

• 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 effects and interactions

Common side effects

• nausea
• diarrhea
• abdominal discomfort
• metallic taste
• decreased appetite

Notable interactions

• iodinated contrast media (major): renal injury risk; hold 48 hours peri-imaging
• alcohol (heavy use) (major): elevated lactic acidosis risk
• cimetidine (moderate): raises metformin plasma levels via OCT2 inhibition
• insulin and sulfonylureas (moderate): additive hypoglycemia risk in combination
• dolutegravir (moderate): raises metformin exposure via OCT2

Lists above cover commonly reported and well-characterized items. They are not exhaustive: review the full Metformin profile and discuss with a clinician familiar with your medication list before starting, particularly if you are on prescription therapy or have a chronic condition.

Regulatory snapshot

WADA status

allowed

DEA / Rx

Rx only (not a controlled substance)

Pregnancy

Category B; used in gestational diabetes and PCOS per current guidance

Legal status

Prescription only (FDA approved for type 2 diabetes 1994)

Do not use if

• eGFR below 30 mL/min/1.73m2
• acute or chronic metabolic acidosis
• severe hepatic impairment
• acute heart failure
• iodinated contrast within 48 hours

Related research