The Truth About Vitamin B12: Why 'Normal' Levels May Not Be Enough

You trust lab results to tell you if you're healthy—but what if they don’t tell the full story? You may feel like you're aging faster, struggling with brain fog, or noticing a dip in energy, yet your vitamin B12 levels appear “normal.” A groundbreaking February 2025 study suggests that current health guidelines for B12 are outdated and insufficient. Researchers found that even within the so-called "normal range," lower B12 levels were linked to slower thinking, neurological decline, and signs of accelerated aging. Is your body craving B12?

Recent Vitamin B12 Study

In this new study, researchers tested vitamin B12 blood levels and completed advanced neurological testing in healthy adults with an average age of 71 years. Results showed that participants who had normal, but lower vitamin B12 levels had increased age-related changes. Results showed slower thinking and reaction times, along with an increased white matter lesions indicating slow brain conductivity, neurological dysfunction and decline. Greater impairments were found in older adults, despite lab values within normal range.

The authors concluded that even though B12 levels in a lab test are within current guidelines, a lower vitamin B12 status impacts cognitive function to a greater extent and affects a greater number of individuals more than previously acknowledged. These findings suggest that even if your lab tests are normal, your brain may not be getting enough B12!

This study falls on the heels of the 2019 Mayo Clinic Proceedings study that recognized that vitamin B12 deficiency is overlooked. They exposed the misconception that you don’t have a vitamin B12 deficiency because your lab test doesn’t show anemia or is within the reference range.

A B12 level of 200-1100 pg/mL is considered to be in the normal range for adults. However, aiming for the higher end of this range is ideal.

Why You Need Vitamin B12

Vitamin B12 is required for numerous functions in your body, including:

• Neurotransmitter metabolism (mood, energy, cognition)

• Estrogen metabolism, menstrual cycle, reproduction

• Histamine clearance

• Phosphatidylcholine production (cell membrane composition and function, intestinal mucus, pulmonary surfactant)

• Creatine and carnitine production (cognition, strength/stamina, mood)

• Myelin production (neurologic, cognitive function)

• DNA synthesis (growth and development)

• Homocysteine metabolism (heart and vascular health)

• Kreb’s cycle (mitochondria for energy production)

• Blood sugar tolerance and metabolism

Who's at Higher Risk for B12 Deficiency?

The most common nutrient deficiency in a plant-based diet is Vitamin B12. The elderly, as well as pregnant and breast-feeding women, those who have had gastric bypass surgery, poor digestion, or consume alcohol have much great risk for B12 deficiency. Several medications deplete vitamin B12. Check with your pharmacist for further information. 

Vitamin B12 Sources

Natural vitamin B12 is found in animal products including shellfish, red meat, poultry, fish, eggs, milk and cheese. Processed foods are fortified with synthetic cyanocobalamin vitamin B12. This low-quality form releases a cyanide group for every molecule of vitamin B12 consumed, which your body needs to then detoxify.

Bioactive Forms of B12

Bioactive forms of vitamin B12 include methylcobalamin, adenosylcobalamin and hydroxycobalamin. We use methylcobalamin and adenosylcobalamin vitamin B12 forms in our nutritional supplements, including:

• Daily Energy Multiple Vitamin

• Daily Prenatal Multiple Vitamin

• Super Mini Multi

• Super Coenzyme B Complex

• B12 + Folate

• Blood Booster

Methylcobalamin is essential for the making of red blood cells, white blood cells, and platelets. It is needed for tissue oxygenation, cardiovascular health, neurological development and function (balance, sensation, smell, movement, thinking, mood, memory), methylation, and a host of other metabolic activities.

Adenosylcobalamin is required for the formation of the myelin sheath, the fatty insulation layer around nerves. Insufficient adenosylcobalamin also leads to disruption of carbohydrate, fat, and protein/amino acid metabolism. This bioactive form of B12 is essential for mitochondrial function and aerobic activity.

Vitamin B12 supplementation does not have any clearly defined adverse effects. No tolerable upper intake level (UL) has been established for B12, due to its low level of toxicity.

All too often, someone’s health concerns are dismissed because their lab test appears normal with its established perimeters. Here we find that in the case of vitamin B12 and more advanced research, normal is not always accurate, especially when you have symptoms. If you find your thoughts and reactions getting slower or any of the above concerns apply to you or your loved ones, consider incorporating high-quality B12 supplements into your routine.

Read more:

Vitamin B12 Essential for Energy, Mood, and Overall Health

B12 and Vitamin D Needed for Rotator Cuff Health

Super Form of Vitamin B12 – Adenosylcobalamin

Recharge Your Vitality: Introducing B12+Folate

Common Medications That Rob the Body of Nutrients