10 Signs Of Vitamin B12 Deficiency You Shouldn’t Ignore

You rely on vitamin B12 for energy, focus, and nerve health every day. It’s easy to overlook how vital it is until your body starts sending signals.

When levels drop too low, you may feel changes in the way you think, move, or feel—often before realizing what’s wrong.

You’ll explore the subtle physical and mental signs that may point to low B12, from constant fatigue to mood shifts and balance changes. This guide helps you understand what your body is trying to tell you so you can take the right steps toward feeling like yourself again.

Fatigue and weakness

You may notice that you feel tired more often, even after a full night of sleep. This ongoing fatigue can make it hard to get through your usual activities.

Low vitamin B12 often leads to this because your body needs it to produce red blood cells that carry oxygen. When oxygen levels drop, your muscles and tissues don’t get the energy they need.

You might feel weak, lightheaded, or short of breath when doing routine tasks. Simple things like climbing stairs or carrying groceries can start to feel harder.

These symptoms can come on slowly, so you might ignore them at first. If your energy levels stay low or you struggle to stay alert, check your B12 levels.

Tingling or numbness in hands and feet

You might notice a tingling or “pins and needles” feeling in your hands or feet when your body lacks enough vitamin B12. This happens because the vitamin plays a key role in keeping your nerves healthy.

Without it, the protective layer around your nerves, called the myelin sheath, can weaken. As the sheath wears down, nerve signals slow or get mixed up.

You may feel numbness, slight burning, or a crawling sensation in your fingers, toes, or even legs. These symptoms often start mild but can slowly worsen if the deficiency continues.

Tingling or numbness from low B12 is called peripheral neuropathy. It often affects both sides of your body in a similar pattern.

If you experience these feelings regularly, talk to a doctor. Foods like meat, eggs, dairy, and fortified cereals provide natural sources of this vitamin.

Difficulty Walking or Balance Issues

You might notice that walking feels harder or that you stumble more often. Low vitamin B12 can affect the nerves that help control movement.

Without enough B12, signals between your brain and muscles don’t work as well. Your legs may feel weak or heavy, and you could find it harder to stay steady, especially when going up stairs or turning quickly.

Some people describe feeling unsteady or dizzy even when standing still. These problems often appear slowly and may be easy to overlook at first.

Pay attention to small changes in your balance or coordination so you can catch a deficiency early.

Memory loss or cognitive difficulties

You might notice that you forget things more often or struggle to think clearly. Low vitamin B12 levels can affect how your brain and nerves work, leading to mild confusion or trouble concentrating.

Your brain relies on vitamin B12 to make healthy nerve cells and support communication between them. When your body doesn’t get enough, these processes slow down, which can cause memory lapses or make learning new information harder.

You could also experience “brain fog,” where your thoughts feel sluggish or unfocused. Some people describe it as having difficulty processing information or staying organized.

Pale or jaundiced skin

You might notice your skin looking paler than usual or slightly yellow. This often happens when your body doesn’t make enough healthy red blood cells.

Without enough of them, less oxygen reaches your tissues, causing your skin to lose its normal color. Sometimes the yellow tint, called jaundice, appears in your skin or the whites of your eyes.

Damaged red blood cells release a substance called bilirubin, which can build up in your body and cause this yellow tint. If you see these changes, it doesn’t always mean you’re low in vitamin B12, but it’s a sign worth checking.

Shortness of breath and dizziness

You might notice shortness of breath or lightheadedness when your body doesn’t have enough vitamin B12. Low B12 levels can reduce red blood cells, which carry oxygen through your body.

When your blood carries less oxygen, your heart and lungs work harder to compensate. You may feel winded more easily when climbing stairs or walking quickly.

Some people also feel dizzy when standing up or moving suddenly. These symptoms may come and go at first, making them easy to overlook.

If they happen often, check your vitamin B12 levels. You can support your B12 levels by eating foods like eggs, fish, and fortified cereals.

Mood changes like depression or irritability

You might notice your mood shifting more than usual when your body lacks enough vitamin B12. This vitamin supports the production of brain chemicals like serotonin and dopamine, which help keep your emotions steady.

When your levels drop, you can feel sad, irritable, or anxious without a clear reason. Low B12 also affects how your brain functions.

Without enough of it, nerve cells and brain chemicals may not work properly, leading to changes in how you think and feel. Some people describe feeling more tired or unmotivated, while others notice increased irritability or mood swings.

If you have lingering low mood or irritability, check your B12 levels with your healthcare provider.

Glossy or Swollen Tongue

If your tongue looks smooth, shiny, or unusually red, you could be low on vitamin B12. This change often happens because your tongue’s tiny bumps, called papillae, start to shrink or disappear.

You might notice that your tongue feels sore, tender, or swollen. Some people describe a burning feeling, especially when eating spicy or hot foods.

A B12 deficiency can also cause glossitis, which means inflammation of the tongue. Your tongue may appear beefy red and slightly puffy.

Pay attention to any changes in your mouth. If your tongue stays red or painful, talk with a doctor or dentist.

Vision problems

Low vitamin B12 levels can affect the nerves that connect your eyes to your brain. When these optic nerves become damaged, signals between your eyes and brain may not transmit clearly.

You might notice blurry or fuzzy spots in your vision. Some people describe seeing shadows or trouble focusing on details.

If your deficiency becomes more severe, you may have double vision or reduced peripheral vision. Scheduling regular eye exams can help catch these issues sooner.

If you already take B12 supplements or receive injections, let your doctor know about any vision changes.

Feeling of pins and needles

You might notice a tingling feeling in your hands, feet, or legs, like tiny pricks under your skin. Many people call this sensation “pins and needles.”

Vitamin B12 helps keep your nerves healthy, and low levels can weaken that support. When your body lacks enough B12, the protective layer around your nerves may start to break down.

Low B12 slows nerve signals and causes numbness or tingling that doesn’t go away quickly. The feeling might come and go at first, then last longer as the deficiency continues.

You may feel it after sitting still for a long time, but unlike normal tingling, it can occur even when you move around.