Feeling unusually tired even after a full night’s rest? This could be one of the earliest indicators of a Vitamin B12 deficiency. B12 plays a key role in helping red blood cells carry oxygen throughout the body. Without enough of it, you may feel drained, weak, or unusually sluggish, no matter how much sleep you get.

Other early signs can include a tingling or “pins and needles” sensation in your hands and feet, which happens when nerves don’t get the support they need. Some people also notice their skin looking paler than usual or slightly yellow-toned due to changes in red blood cells.

Because B12 supports brain health, a shortage may also affect memory, focus, or mental clarity. You might find it harder to concentrate, or you could experience occasional brain fog. Mood changes are another common sign, as low B12 can impact the production of serotonin — the “feel-good” chemical — which may lead to feelings of sadness, anxiety, or irritability.

Shortness of breath or lightheadedness can occur when oxygen delivery throughout the body isn’t at its best. In some cases, people notice a smooth, red, or swollen tongue, known as glossitis, which can be tender and may even change the way food tastes. If left unaddressed, a severe B12 deficiency could affect balance, coordination, or even vision over time.