Is Your “Normal” Vitamin B12 Level Actually Harming Your Brain? Here’s What Science Says

Vitamin B12 is essential for brain health, nerve function, and energy production. You probably already know that a B12 deficiency can cause problems like fatigue, memory loss, and even neurological issues. But here’s what’s shocking: new research suggests that even "normal" B12 levels could be causing hidden damage to your brain!

A recent study published in Annals of Neurology (Beaudry-Richard A, et.al., 2025) looked at healthy older adults and found something surprising—B12 levels within the so-called “normal” range were linked to signs of brain injury and cognitive decline. Let’s break it down.

The Study: What They Found About B12 and Brain Health

Researchers analyzed 231 healthy seniors (average age: 71.2 years) and measured their B12 levels. They then tested their brain function using:

• Visual evoked potential testing: measuring how quickly the brain processes visual signals

• Processing speed tests: checking mental sharpness

• MRI scans: looking for white matter damage

• Blood biomarkers: assessing brain cell injury

Key Findings: Even “Normal” B12 Levels Can Be a Problem

• Low active B12 (holo-transcobalamin) = Slower brain processing and more brain damage.

  • People with lower active B12 had slower reaction times and larger areas of white matter damage (the brain’s communication highways).

• High levels of inactive B12 (holo-haptocorrin) = Higher risk of neurodegeneration.

  • This “storage” form of B12 was linked to higher levels of Tau, a biomarker for Alzheimer’s disease.

What Should You Do?

• Take methylcobalamin supplements because that is the form of B12 which is most important for the nervous system.

• Watch for brain fog, slow thinking, or memory lapses. These could be early signs of B12-related issues, even if your levels are technically “normal.”

The Importance of an Effective B-Complex Formula

To safeguard your brain and overall health, consider our Vitamin B-Complex. Unlike regular B vitamin supplements, our formula contains the physiologically active forms of vitamins B1, B2, B6, and B12, enhancing absorption and effectiveness. Key highlights include:

• Benfotiamine (Vitamin B1) significantly raises blood and tissue levels compared to common forms, protecting your retina, kidneys, and endothelial cells.

• Pyridoxal-5’-phosphate (Vitamin B6) ensures consistent increases in blood levels, essential for cognitive health.

• 5-Methyltetrahydrofolate (Active Folate) offers superior bioavailability compared to standard folic acid, crucial for lowering homocysteine—a risk factor for neurological and cardiovascular conditions.

Buy Now

The Bottom Line

This research suggests that the “normal” range for B12 might not be as safe as we thought. Even if your doctor says your levels are fine, you might still be at risk for neurological damage. The future? Rethinking how we define “healthy” B12 levels and focusing more on what’s actually active in your body.

Want to stay sharp as you age? Keep an eye on your B12—because your brain depends on it.

Reference

Beaudry-Richard A, Abdelhak A, Saloner R, Sacco S, Montes SC, Oertel FC, Cordano C, Jabassini N, Ananth K, Gomez A, Keihani A, Chapman M, Javvadi S, Saha S, Staffaroni A, Songster C, Warren M, Boscardin JW, Kramer J, Miller B, Miller JW, Green R, Green AJ. Vitamin B12 Levels Association with Functional and Structural Biomarkers of Central Nervous System Injury in Older Adults. Ann Neurol. 2025 Feb 10.