Metformin

Metformin Hydrochloride

Evidence & Status

  • FDA Approved
  • Strong Human Evidence
  • Strong

At a Glance

An established prescription medicine for type 2 diabetes with separate, investigational aging research. Observational mortality associations and aging-biology studies do not prove human lifespan extension.

Plain English

Doctors use metformin to help manage type 2 diabetes. Researchers are also studying whether its biology could affect aging, but that is a separate question from its established diabetes use. Observational results can show associations, and aging studies can test biological changes, but neither proves that metformin extends the lives of healthy people.

Overview

Metformin hydrochloride is an established prescription biguanide used for approved metabolic indications, including type 2 diabetes management. The selected DailyMed product anchor is an immediate-release oral tablet, so its formulation-specific dosing and safety information must not be generalized to extended-release products. Aging and longevity research is investigational; metformin is not an established anti-aging or lifespan-extension treatment.

Research Summary

The established evidence base for metformin is its use in type 2 diabetes. Bannister et al. reported retrospective mortality associations in people with type 2 diabetes; those observations cannot establish that metformin extends lifespan or benefit in healthy/non-diabetic people. Barzilai et al. provides scientific rationale for studying metformin in aging and the TAME concept, not completed TAME efficacy evidence. The completed MILES registry record describes a human randomized crossover Phase 4 study of biological effects in older adults with impaired glucose tolerance; a registry record is not proof of lifespan extension. Longevity and healthspan effects remain investigational and unproven.

Research Areas

  • Type 2 diabetes
  • Glycemic control
  • Insulin sensitivity
  • Metformin safety
  • Aging biology research

Safety & Risks

Serious Risks

  • Lactic acidosis: rare but potentially fatal — risk is elevated with renal impairment, hepatic impairment, congestive heart failure, or excess alcohol use
  • Contraindicated when eGFR is below 30 mL/min/1.73m²; use with caution when eGFR is 30–45 mL/min/1.73m²
  • Vitamin B12 malabsorption: long-term use may reduce B12 absorption; periodic serum B12 monitoring is recommended per FDA labeling
  • Iodinated contrast media: temporarily discontinue in patients with eGFR 30–60 mL/min/1.73m² before procedures using iodinated contrast; resume only after renal function is re-evaluated
  • Drug interactions: cationic drugs (e.g., topiramate, cimetidine) may increase metformin plasma concentrations by competing for renal tubular secretion
  • Prescription-only: should never be used without physician supervision, monitoring, and a documented clinical indication

Reported Side Effects

  • Nausea
  • Diarrhea
  • Abdominal discomfort
  • Decreased appetite
  • Metallic taste
  • Vitamin B12 deficiency (with long-term use — monitoring recommended)
United States
FDA-approved prescription metformin hydrochloride products are used for type 2 diabetes; the selected DailyMed product anchor is an immediate-release oral tablet. No longevity or anti-aging indication is established.
United Kingdom
International regulatory status is not represented by the selected sources in this record.
Australia
International regulatory status is not represented by the selected sources in this record.
Canada
International regulatory status is not represented by the selected sources in this record.

Citations & Sources