11 Signs of a Vitamin B12 deficiency

Vitamin B12 is a very chemically complex substance, essential in making red blood cells, nerves and DNA. It helps to regulate our nervous system, plays a key role in growth and development, and every single one of our cells relies on B12 to help regulate metabolism. 

However, it’s what is classed as an ‘essential’ nutrient. We can’t create it, so we have to get it from our diet. It’s also not stored in our body, as the body excretes any B12 that it doesn’t use, so a consistent supply is important to prevent deficiency. 

In the broadest sense, a Vitamin B12 deficiency causes disruptions in the nervous system, the circulatory system, changes in behaviour and mood, and neurological damage, some of which cannot be reversed. You can see why it’s important to make sure that we are managing our B12 requirements effectively. 

Here, we’ll look at what the causes of a deficiency, symptoms to look out for, and how long it might take your body to recover. 

What causes a Vitamin B12 deficiency? 

Vitamin B12 deficiencies are relatively common, and limited dietary intake is only one factor. It’s a big factor, but it’s only one. (Gana et al., 2021)

Whilst a lot of animal products are supplemented with B12, naturally occurring B12 is hard to come by due to intense farming practices. These practices, combined with pesticides and other chemicals, have depleted levels of B12 in our soil. This means that vegans and vegetarians are more likely to have a B12 deficiency than our meat-eating counterparts. 

Age is also a factor. Our ability to absorb B12 declines with age, so older people are likely to have lower levels of B12. This doesn’t mean that younger people can’t have a deficiency, however; everyone needs to keep on top of their B12 intake!

There are also certain medications and medical conditions which can limit the amount of B12 we can absorb. For example, the drug metformin, which is used in diabetes management, can deplete the body’s B12. (W et al., 2019)

If you suspect a Vitamin B12 deficiency, consult a healthcare professional, as they will be able to offer the appropriate testing and, if needed, high strength supplementation. 

What are the symptoms of a B12 deficiency? 

It is important to note that you will start to feel some of the symptoms of B12 deficiency as soon as your levels start to decline - so you might only have a borderline deficiency and still feel symptomatic. 

Fatigue: Our cells need B12 in order to function properly, especially for the formation of new red blood cells (Tardy et al., 2020). Lower levels of B12 means the production rate of new blood cells slows down, and there aren’t as many to carry oxygen around your body, causing a general sense of fatigue, weakness and tiredness. A B12 deficiency can cause a condition called megaloblastic anaemia which leads to abnormal blood cells which cannot function correctly, and impaired DNA synthesis. (Ankar and Kumar, 2019)

Lack of concentration: If you’re having difficulty concentrating, or you’re feeling foggy headed, it might be a sign of a B12 deficiency, and this is also down to the ways in which B12 regulates our central nervous system. This is especially important as we get older, because our ability to absorb B12 decreases with age, and our cognitive functions can also decline with age. Fortunately, mental impairment does appear to be helped by receiving B12 treatments, such as injections or high dose supplements. However, the best way to stave this off is by making sure that you are receiving enough B12 every day. (Nalder et al., 2020)

Headaches: These might be the most common symptom of a B12 deficiency. It has been noted in previous studies that those who suffer from migraines typically have lower levels of B12, and that people with higher levels of B12 are less likely to experience migraines. (Togha et al., 2019)

Balance Issues (Ataxia): A person with a B12 deficiency may well have difficulty with balance and walking - this is a neurological condition. (Ankar and Kumar, 2019)

Depression: There are many different behavioural changes associated with B12 deficiencies, including depression. This is because B12 has a direct impact on regulating and maintaining our central nervous system, so a deficiency can cause changes to your mental health. You are at a greater risk of developing depression if you are deficient in this key nutrient. Low levels of B12 are associated with the body producing higher levels of homocysteine than normal. Homocysteine is an amino acid which contains sulphur as part of its make up, and elevated levels can be directly responsible for DNA damage, oxidative stress within the body and the death of cells within the body, which may in turn increase our risk of developing depression. (Young et al., 2019)

Erectile Dysfunction: Men with low levels of B12 can experience erectile dysfunction as a result of elevated homocysteine levels caused by a lack of B12. (Xu et al., 2021)

Stomach Problems: Gastrointestinal problems can be another sign that something isn’t right within your body. Coupled with other symptoms from this list, any stomach issues you might be facing could be related to a B12 deficiency. These include nausea, constipation, diarrhoea, and bloating. However, It’s worth noting that stomach issues have all kinds of causes, from food intolerances to infections and interactions with medications. (Ankar and Kumar, 2019)

Glossitis: Glossitis is a swelling of the tongue commonly associated with B12 deficiencies, and it often occurs alongside inflammation and pain inside the mouth - a condition called stomatitis. Glossitis causes the tongue to swell, it becomes very red and quite often takes on a shiny appearance. Glossitis and Stomatitis are often early indicators of a lack of B12.  However, it can also be an indicator of deficiencies in other B complex vitamins, such as folate and riboflavin. (Kobayashi and Iwasaki, 2020)

Muscle Cramps : Motor and sensory nerve function is negatively affected by B12 deficiency, which can cause weakness in musculature and more frequent cramps. (Wolffenbuttel et al., 2019)

Pale or Yellow Skin: Again, due to the key role B12 plays in the development of healthy red blood cells, a deficiency might cause a paleness to your skin. This is due to the lack of healthy, oxygenated blood cells. It might also be the cause of jaundice, a condition which causes yellowing skin. This is due to the presence of a substance called bilirubin, which is created when your body breaks down red blood cells. (Ankar and Kumar, 2019)

Pins and Needles (Paresthesia): Everyone gets pins and needles, that slight burning and tingling sensation in our extremities when we sit on our foot for too long, or sleep on our arm but, because B12 deficiencies can cause nerve damage, you might start to experience tingling without having restricted blood flow to the limb in question. As a symptom, Paresthesia overlaps with symptoms associated with diabetes, and can therefore be mistaken in people with diabetes. If you are diabetic, then it is recommended that you consult your doctor frequently regarding your B12 status. (W et al., 2019)

How long does it take to recover from a B12 deficiency? 

If you have a deficiency caused by limited dietary intake, then you might need a course of high strength injections from your doctor. However, if your deficiency is caused by a medical condition or similar, then you might need regular injections or supplementation for life to protect against the damage caused by deficiency. Once you start taking on more B12, then you should start to feel better almost at once! However, if you leave it too long, then some of the damage done might not be reversible. (Ankar and Kumar, 2019)

Taking a Vitamin B12 supplement daily can be a great way of preventing a deficiency in the first place. Vivo Life’s Vegan Liquid B12 supplement offers all the B12 your body needs, ensures optimal absorption and supports a range of physical and psychological functions in the body. Vivo Life Vitamin B12 Blend is in liquid form so it bypasses the digestive system and is absorbed rapidly into the bloodstream for maximum efficacy. So if you’re looking to prevent a B12 deficiency, then look no further! 


W, Y., X, C., H, W. and L, J. (2019). Associations Between Metformin Use and Vitamin B 12 Levels, Anemia, and Neuropathy in Patients With Diabetes: A Meta-Analysis. [online] Journal of diabetes. Available at: https://pubmed.ncbi.nlm.nih.gov/30615306/.

Gana, W., De Luca, A., Debacq, C., Poitau, F., Poupin, P., Aidoud, A. and Fougère, B. (2021). Analysis of the Impact of Selected Vitamins Deficiencies on the Risk of Disability in Older People. Nutrients, [online] 13(9), p.3163. doi:10.3390/nu13093163.

Tardy, A.-L., Pouteau, E., Marquez, D., Yilmaz, C. and Scholey, A. (2020). Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence. Nutrients, [online] 12(1), p.228. doi:10.3390/nu12010228.

Ankar, A. and Kumar, A. (2019). Vitamin B12 Deficiency (Cobalamin). [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK441923/.

Arıcan, P., Bozkurt, O., Cavusoglu, D., Gencpınar, P., Haspolat, S., Duman, O. and Olgac Dundar, N. (2020). Various Neurological Symptoms with Vitamin B12 Deficiency and Posttreatment Evaluation. Journal of Pediatric Neurosciences, [online] 15(4), pp.365–369. doi:10.4103/jpn.JPN_130_19.

Togha, M., Razeghi Jahromi, S., Ghorbani, Z., Martami, F. and Seifishahpar, M. (2019). Serum Vitamin B12 and Methylmalonic Acid Status in Migraineurs: A Case‐Control Study. Headache: The Journal of Head and Face Pain, 59(9), pp.1492–1503. doi:10.1111/head.13618.

Young, L.M., Pipingas, A., White, D.J., Gauci, S. and Scholey, A. (2019). A Systematic Review and Meta-Analysis of B Vitamin Supplementation on Depressive Symptoms, Anxiety, and Stress: Effects on Healthy and ‘At-Risk’ Individuals. Nutrients, [online] 11(9), p.2232. doi:10.3390/nu11092232.

Esnafoglu, E. and Ozturan, D.D. (2020). The relationship of severity of depression with homocysteine, folate, vitamin B12, and vitamin D levels in children and adolescents. Child and Adolescent Mental Health, 25(4), pp.249–255. doi:10.1111/camh.12387.

Nalder, L., Zheng, B., Chiandet, G., Middleton, L.T. and de Jager, C.A. (2020). Vitamin B12 and Folate Status in Cognitively Healthy Older Adults and Associations with Cognitive Performance. The journal of nutrition, health & aging, 25(3), pp.287–294. doi:10.1007/s12603-020-1489-y.

Kobayashi, A. and Iwasaki, H. (2020). Pernicious anemia presenting as glossitis. CMAJ : Canadian Medical Association Journal, [online] 192(16), p.E434. doi:10.1503/cmaj.191331.

Xu, J., Xu, Z., Ge, N., Wang, C., Hu, C., Chen, Z., Ouyang, J. and Pei, C. (2021). Association between folic acid, homocysteine, vitamin B12 and erectile dysfunction-A cross-sectional study. Andrologia, [online] 53(11), p.e14234. doi:10.1111/and.14234.

Wolffenbuttel, B.H.R., Wouters, H.J.C.M., Heiner-Fokkema, M.R. and van der Klauw, M.M. (2019). The Many Faces of Cobalamin (Vitamin B12) Deficiency. Mayo Clinic Proceedings: Innovations, Quality & Outcomes, [online] 3(2), pp.200–214. doi:10.1016/j.mayocpiqo.2019.03.002.