Vitamin B12: the guide

What does vitamin B12 do?

In the terms UK rules allow, B12 contributes to normal energy-yielding metabolism, to the normal function of the nervous system, to normal psychological function, to normal red blood cell formation, to normal homocysteine metabolism, to normal immune function, to a reduction of tiredness and fatigue, and to the process of cell division. That is a long list for a nutrient most people never think about until they are told they are low. The authorised claims do not cover hair, skin, nails, bones or teeth, so anyone selling B12 for your hair has left the evidence behind.

Who is actually short of B12?

Two groups, mainly. The first is anyone eating a plant-based or vegan diet. B12 is made by bacteria and reaches the diet through animal foods, so on a vegan diet a supplement or a fortified food is essential. The second is older adults, who absorb less B12 from food as the gut changes with age. If you are in neither group and you eat meat, fish, eggs or dairy, you are likely getting enough. The reference intake is small, just 1.5 micrograms a day.

The forms, and why the dose looks so big

You will see B12 as methylcobalamin or as cyanocobalamin. Methylcobalamin is an active, ready-to-use form, and it is the one we use. Cyanocobalamin is another common, well-studied form the body converts. Then there is the number that confuses people: the reference intake is 1.5 micrograms, but supplements often contain 1000 micrograms. That is not a mistake. Your body only absorbs a small percentage of an oral dose through the passive route, so a high dose is the practical way to make sure enough gets through. With B12, a large number on the label is normal and sensible.

Spirulina and B12

Spirulina often gets called a plant source of B12, and that is misleading. Spirulina contains a B12-like compound that your body cannot use in the same way, so it is not a reliable source of the vitamin on its own. We add spirulina to our B12 as a whole-food green, not as the B12 itself. The B12 in the product is the 1000 micrograms of methylcobalamin. If you are vegan, that distinction matters, because relying on spirulina alone for B12 is a real and common mistake.

Which should you choose?

For a plant-based routine, a high-dose B12 in an active form covers the gap. Our vegan B12 uses methylcobalamin at 1000 micrograms with added spirulina, and it sits naturally alongside the other nutrients a plant-based diet needs a plan for, like iron, iodine and omega-3.