Metformin as an add-on or Monotherapy in Treatment of Aging People With Multiple Sclerosis (MS)

Treatment tested

• Metformin

Placebo or sham

• Placebo

Other measures (8)

Inclusion Criteria: 1. age between 55 and 75 years old 2. having a diagnosis of MS based on the latest McDonald criteria 3. non-active disease course (no relapses and no MRI activity) in the last 2 years as determined by the MS provider and based on the 2020 revised clinical course criteria 4. EDSS score \<7.0 Exclusion Criteria: 1. inability to undergo MRI scans 2. inability to participate in the study during the study period 3. diabetes or uncontrolled cardiovascular disease 4. unable to consent

The goal of the study is to learn about treating older people with multiple sclerosis (MS) with metformin. Metformin may be used as a single therapy or as an add-on therapy. The investigators want to learn: * The safety and tolerability of metformin extended release (1500 mg/day) as a single therapy or as an add-on therapy in older people with MS compared to placebo * How well metformin protects the nervous system against injury compared with placebo measured by brain MRI over a 9 month treatment period * The effect of metformin to protect brain tissue from age and MS related injury when compared to the placebo group over a 9 month treatment period