Signs Your Body Is Lacking Vitamin B12

Between adulthood and the far too stressful world right now, it can be very easy (and common) to feel sluggish or depressed. And because of all the situational factors around us, it can also be easy to brush off your fatigue and pain as just a product of that. However, there is a thing called vitamin B12, a nutrient that isn't uncommon to lack, resulting in symptoms such as these. So before you brush off your low days for not enough sleep or too much stress in your life, examine your symptoms closer to see if they match vitamin B12 deficiency.

First off, what is vitamin B12? Healthline reported vitamin B12 "is an essential nutrient that your body needs for processes, like DNA synthesis, energy production, and central nervous system function." You can find B12, naturally, in a lot of food such as fish, dairy, eggs, and meat like poultry, as WebMD reported. This means that if you're vegan or have a diet that includes less or no meat, dairy, or eggs, you're not going to be taking in the vitamin B12 you need to stay healthy, meaning you'll have to get it other ways through supplements, vitamins, or food with the nutrient artificially put in. You can find the amount of B12 a product has on the nutrition label.

Who is more likely to become vitamin B12 deficient?

Healthline reported that about "20 percent of people over the age of 60 in the United States and the United Kingdom are deficient" in B12. This is due to multiple reasons, but it's also because the body can't take in as much of it as we age. While that makes it more common in older folks, there are other things that make people more prone to lacking vitamin B12. As mentioned above, certain diets limit the amount of B12 you are naturally taking in, and Healthline reported malabsorption — when you can't properly absorb nutrients — can lead to B12 deficiency. According to WebMD, medications can interrupt vitamin B12 absorption, including certain heartburn medications (PPIs and H2 Blockers) and some diabetes medications.

There are, however, other conditions that could make vitamin B12 deficiency more likely. These include atrophic gastritis, pernicious anemia, Crohn's disease, celiac disease, heavy drinking, Graves' disease, or lupus. Ada, a healthcare support system and knowledge database, wrote that vitamin B12 deficiency can lead to anemia. Whether you have any of these health conditions or your diet sounds like it's lacking vitamin B12-rich foods, how can you tell if you have a lack of the nutrient? These symptoms might shed some light.


Healthline reported that having a low level of vitamin B12 can lead to headaches due to the fact that it can affect the neurological parts of the body. It also doesn't help that if you have chronic migraines or get migraines at all, you have a higher chance of being low in B12 anyway. They report that it's possible that fixing your B12 intake could help with migraines if you have no other underlying cause for these intense headaches, like a disorder or past head trauma, but that's still slightly inconclusive.

Interestingly, there is some debate on whether too much B12 can lead to headaches as well, per Greatist. However, again, you're more likely to get headaches if you lack the nutrient. Greatist reported that headaches are actually "the most common symptom of vitamin B12 deficiency," and those with very high levels of the nutrient were "80 percent less likely to get migraine[s]." Again, if you don't think you have any other health problems that could be causing migraines, you can look into your B12 levels or start taking B12 supplements. Per Healthline, you can get a blood test to check your B12 levels and determine if you for sure have a low level of the nutrient and need treatment for the deficiency or if you should seek other health help.


As stated earlier, fatigue is a common symptom of B12 deficiency that is, unfortunately, also a symptom of so many other things. According to Insider, if you have a mild B12 deficiency, fatigue is likely going to be the symptom you experience. Again, vitamin B12 is used for energy and DNA synthesis, which is why you'll feel sleepy if you don't have enough. Per Healthline, lack of B12 also "decrease[s] normal red blood cell production," meaning your brain isn't getting as much oxygen as it could or should be.

Due to issues with red blood cell production, energy production, and slower oxygen travel, Healthline also reported a lack of this nutrient can lead to difficulty concentrating and other brain fog-related symptoms. Extreme B12 deficiency can really weaken and attack your nervous system, aka your brain. This means you lose mental function and have "mild mental impairment." Just like with migraines, studies show that "84 percent of the participants reported significant improvements in symptoms, like poor focus, memory decline, and forgetfulness" after being treated for low B12 levels.

Off-color skin

Another symptom that is linked to vitamin B12's connection to red blood cell production is having pale or yellow skin. According to another Insider article, most people don't realize they're lacking B12 because their symptoms can be "nonspecific," like fatigue or headaches. However, the symptom of pale or yellowing skin is pretty specific and noticeable.

Express reported that when the body lacks vitamin B12, it loses the "instructions for building the cells," and they're no longer able to divide properly. This leads to anemia, as stated before, particularly megaloblastic anemia. This is when your red blood cells come out "large and fragile," not allowing them to leave your bone marrow, where they're being created, and circulate your body per usual. This leaves your skin without a proper flush; you can exhibit really pale skin because of this. Or your body continues on and is now producing too much bilirubin. And too much bilirubin in the blood causes you to develop jaundice, in which your eyes and skin start to yellow, making yellowing skin a serious symptom of B12 deficiency. Who knew a lack of B12 could cause such a negative domino effect?


As stated before, vitamin B12 can impact your neurological system if you don't get enough of it. While Insider reported that more research needs to be done to definitively determine B12's impact on neurological effects, depression is still a symptom experts point to when someone has a lack of the nutrient. Mayo Clinic reported that B12 and other B vitamins are vital "in producing brain chemicals that affect mood and other brain functions." Just like how a lack of mental functions or brain reactivity can be a symptom of vitamin B12 deficiency, a slowed production of chemicals leading a brain to depression makes sense. Insider classifies this symptom, as well as irritability, impaired cognition, psychosis, and dementia, as symptoms of "severe deficiency."

Again, it's hard to pinpoint just where your depression or low days are coming from. Between a global health crisis, an impending recession, and seasonal changes, depression is, unfortunately, more common right now. But if you notice this symptom among others here, getting a B12 test will rule it out or show that you need some supplements to get it back up. Always talk to a healthcare provider about questions regarding your health, and chat with a mental health professional like a therapist if you're feeling particularly down.

If you or someone you know needs help with mental health, please contact the Crisis Text Line by texting HOME to 741741, call the National Alliance on Mental Illness helpline at 1-800-950-NAMI (6264), or visit the National Institute of Mental Health website.

Pain and burning in different body parts

Lastly on our list is paresthesia and other pain your body can experience due to a lack of vitamin B12 in your body. As Insider reported, this symptom is caused by a "moderate deficiency." At this point in B12 deficiency, you can experience "peripheral neuropathy, or damage to the nerves outside the brain and spinal cord." This includes "sensory problems" such as paresthesia, which is that pins-and-needles feeling in your hands or feet after they fall asleep (but of course, you experience it without the falling asleep part). Paresthesia can be a symptom of diabetes as well, which isn't helped by the fact that certain diabetes medications (as stated before) can lead to a lack of B12, per Healthline. They reported that if you're on metformin for diabetes, experts suggest testing for your B12 levels as well.

These sensory problems can also include being numb in your hands and feet or developing glossitis, which is "tongue inflammation that might result in sensitivity to spicy or acidic food."