Metformin quandary : Brain shield or B12 thief?

Metformin, widely prescribed for diabetes, is now being studied for its potential to rejuvenate the brain by activating the hypothalamus and reducing toxic proteins. However, long-term use has been linked to Vitamin B12 deficiency, which elevates homocysteine levels and increases the risk of stroke.

Hyderabad: Metformin, the cost-effective and workhorse drug that is most commonly used by diabetics, has now become a major source of conversation among doctors and drug developers for its new properties.

New evidence has now confirmed that Metformin acts directly on the brain’s hypothalamus, which is popularly known as the brain’s smart control centre. And yet, there are also studies indicating that patients who are on metformin for a long time can be deficient in Vitamin B12.

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Researchers have found that Metformin crosses the blood-brain barrier to activate the body’s metabolic master switch in the brain, effectively ‘cleaning’ neural cells of toxic proteins. In some primates, the studies have also indicated a reduction in brain age by an average of six years.

However, city-based neurologist and popular health communicator (hyderabaddoctor on X), Dr Sudhir Kumar, recently spoke about the link between Metformin and Vitamin B12 and its hidden impact on the nervous system.

There are studies indicating that Metformin also interferes with B12 absorption in the gut, with the risk of deficiency spiking significantly at doses of 1500 mg/day or higher.

This deficiency leads to elevated homocysteine levels, suggesting that the damage occurs at the tissue level, Dr Sudhir said.

High homocysteine is a known red flag for stroke and cerebral venous sinus thrombosis, creating a metabolic irony where a drug meant to protect the brain could inadvertently harm it.

To utilise Metformin judiciously, the medical consensus is shifting toward a more holistic monitoring approach. While Metformin drug remains a powerful tool for aging and diabetes, it is also equally vital to monitor the status of Vitamin B12 in the human body from time to time, advises Dr Sudhir.

Patients must periodically check their B12 levels and use supplements as recommended by their doctors to prevent vascular brain injury and ensure long-term neuroprotection, doctors added.