Vitamin B12 Spray: Does It Work? Spray vs Tablets vs Injections (UK)

What is a B12 spray?

A B12 spray is a liquid vitamin B12 supplement in a small pump bottle. You spray it onto the inside of your cheek or under your tongue, usually once a day. Most UK sprays use methylcobalamin, and the daily dose on the label ranges from about 250 to 1,200 micrograms, far above the 1.5 micrograms adults need from food.

For a fuller look at tablets, forms and food sources, see our guide to vitamin B12 supplements.

Do B12 sprays work?

B12 sprays can raise blood B12 levels in people who need more, because a small share of any large B12 dose is absorbed whatever route it takes. But independent trials of mouth sprays are scarce. Most evidence comes from swallowed and under-the-tongue tablets, which work about as well as each other.

How is B12 from a spray absorbed?

From food, B12 is absorbed in the small intestine with the help of intrinsic factor, a protein made in the stomach. That route fills up at about 1 to 2 micrograms per meal, according to the US National Institutes of Health. Above that, a much smaller share gets in by passive diffusion, which doesn’t need intrinsic factor. A small study in older adults found about 2% of a 1,000 microgram dose was absorbed through the nose, similar to swallowing it.

Spray makers say B12 passes through the lining of the cheek. Some may, but much of each spray is swallowed with saliva, so a spray behaves much like a high-dose tablet. The dose matters more than the format.

B12 spray vs tablets vs injections

A B12 spray, a swallowed tablet and an under-the-tongue tablet all work for most people who need extra B12, as long as the dose is high enough. Choose the one you’ll take every day. Injections are different: they’re prescribed for people who can’t absorb B12 from the gut or who have severe symptoms.

NICE advises anyone choosing a shop supplement to pick one containing cyanocobalamin, methylcobalamin or adenosylcobalamin, because some products don’t contain enough, or the right type, of B12 to work. Methylcobalamin is fine, but there’s no good evidence it beats cyanocobalamin for most people. Liquid formats are common in the shops: our guide to magnesium spray covers the same question for magnesium, and gummy vitamins vs pills compares other formats.

Who needs a B12 supplement?

Most people in the UK get enough vitamin B12 from meat, fish, eggs and dairy. The people who should think about a supplement are vegans, some vegetarians, older adults, people taking metformin or long-term acid-reducing medicines, and anyone who has had stomach or bowel surgery. If you have symptoms, see a GP before buying anything.

• Vegans: B12 isn’t found naturally in plant foods. The Vegan Society advises fortified foods two or three times a day (at least 3 micrograms a day), a daily supplement of at least 10 micrograms, or a weekly supplement of at least 2,000 micrograms. Spirulina isn’t a reliable source; see the spirulina B12 myth.
• Older adults: autoimmune gastritis and low stomach acid become more common with age, so B12 from food is absorbed less well. The NHS says pernicious anaemia is the most common cause of B12 deficiency in the UK.
• People on metformin: the MHRA says reduced B12 is a common side effect, especially at higher doses and with longer use. See does diabetes make you tired?
• People on PPIs or H2 blockers: NICE lists omeprazole-type medicines and H2 blockers among the risk factors, because less stomach acid releases less B12 from food.
• Others NICE lists: stomach or bowel surgery including many weight-loss operations, coeliac disease, some epilepsy medicines and recreational nitrous oxide.

How much B12 spray should I take?

Follow the label, which is usually one to four sprays a day giving 250 to 1,200 micrograms. That is plenty for vegans and most people topping up. The NHS says 2mg (2,000 micrograms) or less a day from supplements is unlikely to cause harm. If you have a diagnosed deficiency, your GP sets the dose and the form.

NICE recommends at least 1mg (1,000 micrograms) a day when a doctor prescribes oral B12 for a deficiency caused by poor absorption, and lifelong injections when autoimmune gastritis is the cause. A spray bought in a shop isn’t a substitute for either without your GP’s agreement.

Can a B12 spray help with tiredness?

Vitamin B12 contributes to the reduction of tiredness and fatigue, which is an authorised health claim in Great Britain. It’s allowed on products that are at least a source of B12. But if your B12 level is already normal, extra B12 hasn’t been shown to give you more energy, so a spray is unlikely to fix tiredness with another cause.

Other authorised claims include that vitamin B12 contributes to normal energy-yielding metabolism and normal red blood cell formation. Tiredness has many causes, from sleep and low iron to thyroid problems: see why am I always tired? and iron deficiency symptoms. For other nutrients, see our B vitamins guide and best supplements for energy.

Get tested before you start

If you have symptoms such as tiredness with pins and needles, a sore red tongue, mouth ulcers, problems with memory or balance, or shortness of breath, see a GP for a blood test before you take B12. NICE advises taking blood samples before starting B12, because supplements raise blood levels and can make a real deficiency harder to diagnose.

iTell your GP or the person taking your blood if you already use a spray, tablets or patches, and what dose. Nerve symptoms from low B12 need prompt treatment: see vitamin B12 deficiency symptoms and peripheral neuropathy.

B12 spray safety and medicines

• Metformin, PPIs and H2 blockers: keep taking your medicine. Ask your GP or pharmacist whether your B12 should be checked, rather than stopping a prescription on your own.
• Pregnancy and breastfeeding: the NHS says you can usually take B12, but check with a pharmacist, midwife or GP first.
• Cobalt allergy: B12 contains cobalt, and the NHS says cyanocobalamin may not suit people allergic to it.
• How much is too much: see can you overdose on vitamins?