{"id":629859,"date":"2024-09-23T13:43:44","date_gmt":"2024-09-23T17:43:44","guid":{"rendered":"https:\/\/www.singlecare.com\/blog\/?p=629859"},"modified":"2026-01-28T14:08:20","modified_gmt":"2026-01-28T19:08:20","slug":"metformin-and-vitamin-b12","status":"publish","type":"post","link":"https:\/\/www.singlecare.com\/blog\/metformin-and-vitamin-b12\/","title":{"rendered":"Metformin and vitamin B12: What you should know"},"content":{"rendered":"

Metformin, <\/span>an <\/span>anti-diabetic medication<\/span><\/a>, is a popular prescription drug to help manage blood glucose levels for those with <\/span>diabetes mellitus<\/span><\/a>. However, a common risk factor of taking metformin is low vitamin B12 levels, which can cause fatigue, mood changes, changes in cognitive function, and more.<\/span><\/p>\n

If the use of metformin is affecting your vitamin B12 levels, a supplement and diet changes may help. Learn everything the experts have to say about taking a vitamin B12 supplement when on metformin.<\/span><\/p>\n

How does metformin affect vitamin B12 levels?<\/span><\/h2>\n

Before understanding how metformin can affect a person\u2019s vitamin B12 levels, it\u2019s helpful to better understand how the commonly prescribed drug and vitamin B actually work.<\/span><\/p>\n

Metformin is an antidiabetic prescription drug that belongs to a class of medications called biguanides. It helps regulate blood sugar levels for those with Type 2 diabetes or gestational diabetes by increasing insulin sensitivity, decreasing glucose production by the liver, and decreasing glucose absorption from the intestines. Metformin treatment is also sometimes used for those who experience insulin resistance.<\/span><\/p>\n

Vitamin B12, also known as cobalamin, is one of the B vitamins under the umbrella of the vitamin B complex, which includes eight different types of vitamin B. This essential nutrient has <\/span>many important functions<\/span><\/a> in our body, including DNA synthesis, nerve function, red blood cell production, and metabolism. It is commonly found in foods of animal origin, like meats, fish, dairy, and eggs. A deficiency in vitamin B12 can cause a wide range of side effects, from mood changes to anemia to heart palpitations.<\/span><\/p>\n

How exactly can metformin affect vitamin B12 serum levels?<\/span><\/h3>\n

\u201cMetformin reduces vitamin B12 absorption in the gastrointestinal tract,\u201d explained Dr. Farhan Malik, MD, Owner and Senior Medical Director at Prometheus by Dr. Malik. He further added, \u201cThe reduction in B12 absorption is thought to be due to metformin altering gut mobility and intestinal cell membrane function.\u201d<\/span><\/p>\n

The gut is a sensitive system, and it\u2019s easy for the absorption of vitamin B to be compromised \u2014 even for those not taking metformin.<\/span><\/p>\n

\u201cThe B12 absorption pathway is a very complex pathway and can be disrupted in many different ways, including stomach acidity, taking certain antacids, or even having inflammation in the gut,\u201d said Dr. Sulagna Misra, an<\/span> internal and integrative medicine physician and owner of <\/span>Mirsa Wellness<\/span><\/a>.<\/span>\u00a0<\/span><\/p>\n

Metformin does not affect B12 levels instantly. It can take months and years for patients with diabetes taking the drug to begin noticing symptoms of a B12 deficiency. Short-term metformin users are at less risk of developing a deficiency, while long-term use of metformin therapy can increase the risk of vitamin B12 deficiency.<\/span><\/p>\n

How do I know if my B12 levels are too low?<\/span><\/h2>\n

Initially, symptoms of a low vitamin B12 level can be subtle; perhaps you\u2019ll start experiencing general fatigue, dizziness, or weakness. Over time, these symptoms will get worse as the deficiency continues.\u00a0<\/span><\/p>\n

If you suspect your B12 levels are off, your primary healthcare provider can take blood samples to determine if your levels are normal or deficient. A B12 level above 300 picograms per milliliter (pg\/mL) will be <\/span>interpreted as normal<\/span><\/a>. Borderline deficient levels between 200 and 300 pg\/mL may need further testing. Providers may order a blood test called methylmalonic acid level, which can show early B12 deficiency before it shows up on standard testing. If blood testing finds levels under 200 pg\/ML, these patients are considered deficient in B12.<\/span><\/p>\n

There are several symptoms associated with a <\/span>vitamin B12 deficiency<\/span><\/a>, which we\u2019ve listed below.<\/span><\/p>\n

Vitamin B12 deficiency symptoms when taking metformin<\/span><\/h3>\n