Signs of Vitamin B12 Deficiency

Low energy, brain fog, and mood swings aren’t always caused by stress or a busy schedule. In many cases, these issues can be linked to a nutrient imbalance, specifically low vitamin B12. Because this vitamin is essential for energy production, nerve health, and blood cell formation, even a mild deficiency can have a big impact on how you feel day to day. (1)

What makes vitamin B12 deficiency tricky is that the symptoms often build slowly and can mimic other health concerns. Some men may think their symptoms are a result of simply being tired from work, getting older, or operating under too much day-to-day pressure. However, in many cases, your body may be signaling a lack of this critical nutrient. Recognizing these signs early is the best way to prevent more serious health problems down the road.

In this article, we will look at why vitamin B12 is so important for men’s health, the common signs and symptoms of low vitamin B12, who is most at risk, and the best ways to test, treat, and prevent deficiency.

 

Why Vitamin B12 Matters for Men’s Health

Vitamin B12 is a powerhouse nutrient that supports some of the body’s most critical functions. Unlike some vitamins that play minor or overlapping roles, B12 is central to energy, brain function, and blood health. When levels dip, men often feel it across multiple areas of their well-being.

Role in Energy and Metabolism

Vitamin B12 helps convert food into usable energy by supporting the metabolism of carbohydrates, fats, and proteins. It serves as a cofactor for enzymes involved in cellular metabolism, particularly in the conversion of methylmalonyl-CoA to succinyl-CoA and in methionine synthesis. (2) Without enough B12, the body struggles to fuel muscles and organs efficiently, leading to sluggishness, poor stamina, and difficulty recovering after workouts.

Nervous System and Brain Health

Vitamin B12 also plays a key role in neurological function. It helps maintain the protective sheath (myelin) around nerves, which ensures clear communication between the brain and body. Low levels can lead to nerve-related symptoms, brain fog, and severe mood disturbances. (3)

Blood Cell Formation and Oxygen Delivery

Vitamin B12 plays an essential role in producing red blood cells, which carry oxygen throughout the body. A deficiency can cause megaloblastic anemia, characterized by the production of abnormally large, immature red blood cells that cannot carry oxygen effectively.  This reduces oxygen delivery and leaves men feeling persistently tired, short of breath during activity, and more prone to dizziness.

 

Common Signs of Vitamin B12 Deficiency

A lack of vitamin B12 can show up in many ways. Some signs are subtle, while others are disruptive to daily life. Knowing what symptoms to look for can make it easier to catch a deficiency early. Here are some of the biggest signs to look out for. (4)

Fatigue and Low Energy

One of the most common symptoms of low vitamin B12 is fatigue. Men with a deficiency may feel drained even after a full night’s sleep, and many describe hitting an invisible wall during the day that makes it difficult to complete any task.

Weakness and Muscle Loss

Deficiency can cause muscle weakness or a gradual loss of muscle mass. Everyday tasks may feel harder than they used to, and workouts might leave you unusually sore. Over time, strength may decline because the muscles are not receiving enough oxygen-rich blood.

Mood Changes, Brain Fog, and Depression

Irritability, forgetfulness, and low mood are frequent complaints. The brain depends on vitamin B12 for neurotransmitter balance and focus. Deficiency can contribute to anxiety or depressive symptoms, making men feel unlike themselves.

Pale or Jaundiced Skin

When red blood cell production is impaired, skin may appear unusually pale or take on a yellow tint. The yellow tint occurs due to increased breakdown of the abnormal red blood cells, releasing bilirubin. Others may notice this change before you do, and it can lead to an overall tired look.

Tingling, Numbness, or Nerve Pain (Neuropathy)

Nerve issues are another hallmark of vitamin B12 deficiency. Tingling in the hands or feet, numbness, or sharp nerve pain may occur. This can interfere with daily activities such as typing, holding objects, or walking comfortably.

Glossitis and Mouth Ulcers

A sore, red tongue and recurring mouth ulcers can be signs of underlying deficiency. Some men also experience a burning sensation in the mouth or changes in taste.

Vision Changes

In rare cases, low B12 damages the optic nerve, leading to blurred or disturbed vision. Left untreated, this can become a long-term problem.

 

Who Is Most at Risk of B12 Deficiency?

Not everyone has the same risk of developing low B12. Older men often develop atrophic gastritis or reduced intrinsic factor production, which impairs B12 absorption, Vegans and vegetarians may also have a higher risk of B12 deficiency, since B12 is mostly found in animal products. (5)

 

Several other factors can increase risk, including if you have a family history of the disease or have had part or all of your stomach or intestine removed. Other risk factors include having been diagnosed with conditions such as Crohn’s disease, celiac disease, type 1 diabetes, or HIV. (6)

Men who take metformin for diabetes or proton pump inhibitors (PPIs) for acid reflux, may also have a higher risk of B12 deficiency, as these medications can sometimes block absorption.

 

How to Test and Treat Vitamin B12 Deficiency

If you suspect a deficiency in vitamin B12, testing is straightforward and highly effective for identifying the problem.

Typical lab work includes a serum vitamin B12 test, along with additional markers like methylmalonic acid and homocysteine for confirmation. Blood tests can show whether you have a lower level of haemoglobin, if your red blood cells are larger than normal, and the level of folate in your blood. (7) These tests help determine not only if levels are low, but also if they are low enough to be causing symptoms.

Once diagnosed, treatment depends on the severity and underlying cause. For men with mild deficiencies, oral supplementation may be enough. However, many cases require B12 vitamin injections, which bypass the digestive system and deliver the vitamin directly into the bloodstream. Injections are especially beneficial for men with absorption issues, since supplements may not raise levels effectively on their own.

At Gameday Men’s Health, treatment for this deficiency typically follows a step-by-step process:

1. Initial consultation to review symptoms and risk factors 
2. We offer lab testing to confirm deficiency 
3. Treatment with B12 injections or IV therapy based on each patient’s individual needs 
4. Regular follow-ups to monitor progress and adjust B12 dosing and frequency 

This approach ensures that the deficiency is corrected, and that men also feel the difference in mood, energy, and performance following their treatment.

 

Prevention Tips and Lifestyle Considerations

Even if you are not currently deficient, there are several easy ways you can protect your B12 levels as you age. While these tips won’t guarantee you won’t become deficient in Vitamin B12, they can lower your overall risk and make any future deficiencies more manageable. 

• Include foods rich in vitamin B12, such as beef, chicken, salmon, tuna, eggs, dairy products, clams, sardines, and fortified cereals (8) 
• If you are vegetarian or vegan, consider fortified plant milks, nutritional yeast, or supplements as part of your daily routine 
• Schedule routine bloodwork after age 30 to catch potential deficiencies early 
• Talk with your healthcare provider about risks if you are on long-term medications that interfere with absorption

To put it into perspective, one serving of salmon can provide nearly your entire daily requirement of B12, while fortified breakfast cereals can give plant-based eaters an easy morning boost. Adding variety to your diet and checking levels regularly is often the simplest way to prevent problems before they start.

 

Taking Action Against Vitamin B12 Deficiency

Vitamin B12 deficiency is more common than many men realize. For those with a deficiency, the effects can show up in many different ways including fatigue, weakness, mood changes, and nerve pain. 

Left unchecked, a B12 deficiency can lead to long-term health concerns, but the good news is that testing and treatment are straightforward.

If you feel you may be suffering symptoms of a B12 deficiency, it’s important not to ignore them and to seek medical treatment from a trusted healthcare professional such as your local Gameday Men’s Health location. Early action through testing and treatment can restore your health and prevent future complications.

If you’re ready to help take back control over your health and boost your Vitamin B12 levels, contact your local Gameday location to take the first step toward renewed strength, energy, and vitality.  

 

References

1. Vitamin B12: What to Know 
2. Reversible Vitamin B12 Deficiency Presenting with Acute Dementia, Paraparesis, and Normal Hemoglobin 
3. Vitamin B12 deficiency can be sneaky and harmful 
4. Vitamin B12 Deficiency 
5. Exploring Vitamin B12 Supplementation in the Vegan Population: A Scoping Review of the Evidence 
6. Vitamin B12 Deficiency Anemia
7. Diagnosis Vitamin B12 or folate deficiency anaemia 
8. Top 12 Foods That Are High in Vitamin B12