But just because you develop any of these symptoms, it doesn’t necessarily mean that you have a vitamin B12 deficiency.
Mouth ulcers, for example, are very common and should clear up by themselves within a few weeks.
They’re rarely caused by anything serious, and you don’t need to see a doctor unless the ulcer lasts for more than three weeks.
Glossitis, meanwhile, may simply be caused by eating spicy foods or wearing braces.