Vitamin B12 is necessary for ensuring that red blood cells, brain function, and nerve tissue remain healthy and productive. The human body can store several-years-worth of B12, although people following a vegetarian or vegan diet or those with absorption issues are at risk of deficiency. A vitamin B12 deficiency or cobalamin deficiency is relatively common -- there are more than 3 million cases of vitamin B12 deficiency in the United States alone.

Loss of Muscle Strength

When doctors cannot trace muscle fatigue to a specific issue such as an over-the-top workout or a recent illness, they may look into a vitamin B12 deficiency. Too little of this vital nutrient can restrict the amount of oxygen reaching the red blood cells, which affects muscle strength to varying degrees.



One of the first signs of a vitamin B12 deficiency is frequent mental and physical fatigue regardless of how much sleep the person is getting. If an individual consistently gets a full eight hours of sleep every night and is still falling asleep during lunchtime, then a lack of vitamin B12 could be to blame. Much like muscle fatigue, too little oxygen in the red blood cells can lead to chronic lethargy.



Everyone tends to be a little forgetful at times. However, when this becomes the norm, it may be time to see a doctor for blood tests, which could reveal a B12 deficiency. Yet again, it is lack of oxygen in the blood -- this time the blood being delivered to the brain -- that causes this symptom.


Pins and Needles

Another early warning sign of a vitamin B12 deficiency is a feeling of electrical charges through the body. Many individuals describe a pins and needles sensations similar to the prickly feeling that comes from sitting on one foot or laying on one arm for too long. Like most symptoms of vitamin B12 deficiency, this is a result of too little oxygen in the red blood cells.


Pale Skin

Ashen skin on a person who has been receiving sufficient sunlight can indicate a vitamin B12 deficiency. Lack of oxygen in the blood prevents the rosy glow generally associated with good health. Individuals may also experience yellow or jaundiced skin coloring; this occurs if red blood cells become fragile, breaking apart quite easily. This breakdown releases bilirubin, the cause of jaundice.



Feeling dizzy for no reason can be an early warning sign of a vitamin B12 deficiency. Most people notice this symptom especially when they stand or sit too quickly, or when walking up a flight of stairs, and it usually comes on and passes quickly. Dizziness is often attributed to other factors, especially in the elderly, and B12 deficiencies are often overlooked.



Vitamin B12 is crucial for overall mental health. Some people with insufficient B12 experience anxiety and depression, with varying intensity. When such symptoms, which many people feel from time to time, do not ebb when the issue in question passes or is resolved, the feelings could indicate a vitamin deficiency or any number of other health concerns.


Changes in the Tongue

All healthy people have little bumps across the surface of their tongues called papillae. Some patients experiencing vitamin B12 deficiency may notice these bumps appear to vanish when the tongue becomes inflamed, a condition called glossitis. Some may also experience soreness along the back side of the tongue or a burning sensation.


Vision Changes

Sometimes patients with a vitamin B12 deficiency may also experience vision problems including fuzzy spots, blurry vision, peripheral shadows, and double vision. While these issues are symptomatic of many conditions, they can also result from insufficient vitamin B12. Although rare, optic neuropathy is a serious complication of a B12 deficiency where the optic nerve becomes brittle and damaged, sometimes resulting in central vision loss.


Weight Loss

Weight loss can result from vitamin B12 deficiencies. The changes to the tongue that cause the papillae to "disappear" directly affects the taste buds, which are contained within. As a result, an individual may eat less and subsequently lose weight.


Balance Problems

When vitamin B12 levels are insufficient, it can lead to nerve damage which can cause problems with balance and coordination. This is particularly noticeable in older individuals, but it can affect people of all ages. If you find yourself stumbling or tripping more frequently without an obvious cause, it might be time to consider a B12 deficiency as the underlying issue.

Dizzy woman suffering vertigo attack standing in the living room at home



While not a direct symptom of tinnitus, ringing or buzzing in the ears when there's no external sound source can be a sign of neurological issues related to B12 deficiency. While tinnitus can be caused by various factors, including B12 deficiency, it's often overlooked as a potential symptom. If you're experiencing persistent tinnitus, especially in conjunction with other signs on this list, consult a healthcare professional.

Tinnitus concept. Close up up of sick young caucasian female touch plug ear suffer from noisy disturbing sound sitting on sofa at home. Annoyed millennial lady having earache, hearing problems


Heart Palpitations

Irregular heartbeats or palpitations can be another indicator of vitamin B12 deficiency. These palpitations can be unsettling and may be accompanied by a feeling that your heart is racing and lightheadedness. If you're experiencing heart palpitations, it's essential to rule out nutritional deficiencies, such as low iron, as a potential cause. Both low iron and a B12 deficiency can interfere with the body's ability to produce healthy red blood cells causing anemia and leading to heart palpitations.

Elderly Asian man with chest pain from a heart attack, His wife was worried when she saw her husband sick, congenital disease, Heart disease, High blood pressure.


Shortness of Breath

Vitamin B12 is essential for the production of healthy red blood cells. When B12 levels are low, it can lead to a reduction in the number of red blood cells and cause anemia. Anemia, in turn, can result in shortness of breath, even with minimal physical activity. It is red blood cells that carry oxygen throughout your body. If you find yourself unusually breathless during everyday tasks, consider a B12 deficiency as a potential reason.

Coronavirus, covid-19 and quarantine concept. Sick man with shortness of breath symptom


Changes in Taste and Smell

A deficiency in vitamin B12 can affect your olfactory function. That is you may notice changes in how foods taste or things smell. Some individuals report a metallic taste in their mouths, while others have experienced a diminished sense of smell. These alterations can impact your appetite and overall enjoyment of food. This again is an indirect symptom related to neurological issues caused by a vitamin B12 deficiency and is often overlooked.

Senior woman holding plate of bad spoiled or expired food in her hand,rotten food,emitting a fetid smell or strong-smelling food,disgusted old elderly cover nose with her finger,diet,nutrition concept


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This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.