Is the B12 in supplements vegan?

The question comes up because the premise sounds contradictory. B12 is the nutrient you are told a plant diet cannot supply, and then you are told to take a supplement of it. Where does the supplement get it from?

The regulation answers it directly

Most origin questions on this site require working backwards from a manufacturing process, because the label will not say. This one does not.

The US rule affirming vitamin B12 as generally recognised as safe opens by stating that it “is produced commercially from cultures of Streptomyces griseus”.

That is a soil bacterium. No animal is involved, and the statement is part of the regulatory definition rather than a manufacturer’s claim.

Why that is not a loophole

It follows from the biology rather than working around it.

Animals do not make B12 either. Bacteria make it, and animals accumulate it from bacteria in their gut or their food. Growing the bacteria and taking the vitamin directly is the shorter path to the same molecule, not a substitute for it.

This is the same pattern as Vitamin D3 produced from lichen instead of sheep wool, and as the fermentation-produced enzymes that replace animal Rennet in cheese. In each case the industrial route reaches the original producer and skips the animal in the middle.

What can still catch you out

The active ingredient is the easy part. Two things around it are harder.

The capsule. This is the common failure. A B12 capsule shelled in Gelatin is not vegan whatever is inside it, and gelatin is an animal product. Hypromellose is the plant alternative and it is named in the ingredient list, which is covered in the question on supplement capsules.

The fermentation medium. What the bacteria were fed is not on the label at all. It is a manufacturing question rather than a labelling one, and it is one of the reasons certification bodies exist. If that level of assurance matters to you, a certification mark on the pack carries information the ingredient list cannot.

The part that is not a label question

Whether you need B12, and how much, is not something an ingredient list can tell you. The NHS puts adult requirement at about 1.5 micrograms a day and notes that vegans may not get enough from diet alone.

Stores in the body last years, so a shortfall builds slowly and quietly. That makes it a blood test and a conversation with a doctor rather than something to settle by reading a pack, which is the fuller picture on Cyanocobalamin.