If you’re asking about signs of vitamin B12 deficiency that people often overlook, several symptoms can be subtle at first.
Commonly overlooked signs
- Persistent tiredness or weakness — B12 deficiency can contribute to anemia.
- Tingling or numbness — particularly in the hands or feet. Nerve symptoms can occur even without anemia.
- Balance or walking problems — more concerning when they develop gradually.
- Brain fog or difficulty concentrating — some people experience memory or cognitive changes.
- A sore, smooth, or unusually red tongue and mouth ulcers.
- Pale or yellowish skin.
- Mood changes, including irritability or low mood.
- Vision problems in more advanced cases.
B12 deficiency is more likely in people with conditions affecting absorption, those who’ve had certain gastrointestinal surgeries, people taking metformin or acid-suppressing medications long-term, and people following a vegan diet without reliable B12 supplementation.
If you have persistent symptoms—especially numbness, weakness, balance problems, or cognitive changes—it’s worth discussing them with a clinician. A blood test can help determine whether B12 deficiency is actually present.
Don’t take high-dose B12 simply because you have these symptoms: many other conditions can cause the same symptoms, and some neurological problems are better treated when their actual cause is identified promptly.
