Vitamin B12 helps your body make red blood cells and keep nerves healthy, so running low can leave you tired, foggy and short on energy. Women who eat little meat, take certain medications or are over 50 are most at risk — and a simple blood test can confirm it.

Why does vitamin B12 matter so much for energy?

B12 is a little like the spark plug in a car engine: you don't need much of it, but without it the whole system sputters. Your body uses B12 to build healthy red blood cells that carry oxygen around your body, and to maintain the protective coating around your nerves. When levels drop, red blood cells become fewer and larger than they should be, so less oxygen reaches your tissues. The result is often a deep, persistent tiredness that a good night's sleep doesn't seem to fix.

What are the signs of low B12 in women?

Because B12 affects both blood and nerves, the symptoms can be wide-ranging. Commonly reported signs include ongoing fatigue, brain fog, memory lapses, mood changes, pale or slightly yellowish skin, heart palpitations, breathlessness, and pins-and-needles or numbness in the hands and feet. Some people also notice a sore or swollen tongue. These overlap with plenty of other things — iron deficiency, stress, poor sleep — which is exactly why low B12 is worth checking rather than guessing at.

Who is most likely to run low?

B12 occurs naturally only in animal foods, so vegetarians and vegans are more likely to fall short without a supplement or fortified foods. Absorption matters as much as intake: conditions like pernicious anaemia, a history of gastric or weight-loss surgery, and long-term use of metformin or acid-reducing medications (PPIs and H2 blockers) can all interfere with how much B12 you actually absorb. Pregnancy and breastfeeding raise your needs, and the risk of pernicious anaemia climbs after 50. If several of these apply to you, low B12 is more than a passing worry.

How can you support healthy B12 levels?

For most people, food is the foundation: eggs, dairy, fish and lean meat are reliable sources, while those eating plant-based can lean on fortified plant milks, nutritional yeast and fortified cereals. If you follow a largely vegan or vegetarian diet, a B12 supplement is one of the few genuinely worth taking routinely. Pairing a nutrient-dense daily habit — like a greens blend such as our Supergreens Antioxidant Juice — with B12-rich or fortified foods can help round out a busy diet, though greens are a complement to, not a replacement for, dedicated B12 sources. And if you suspect a deficiency, the most useful step is a blood test: supplementing blindly can blur symptoms without addressing the cause.

Frequently asked questions

Can I have low B12 even if I eat meat? Yes. If your body doesn't absorb B12 well — because of medication, a gut condition or age — you can run low despite a meat-rich diet. Absorption, not just intake, is the deciding factor.

How long does it take to feel better after correcting B12? It varies. Some people notice more energy within a few weeks, but nerve-related symptoms can take longer, and any correction should be guided by your doctor based on your levels.

Is more B12 always better? Not really. B12 is water-soluble and excess is usually excreted, but megadoses aren't a shortcut to more energy if your levels are already healthy. Testing first is the sensible route.

This article is for general education and is not medical advice. Supplements support — not replace — good habits and medical care. If you're pregnant, breastfeeding, taking medication or managing a health condition, please check with your doctor or pharmacist before starting anything new.