Best vitamin B12 supplements: reviewed by nutrition experts

Vitamin B12 is an essential nutrient for energy and nerve function. It's one of the more common nutrient deficiencies in the UK.

While most people should be able to get enough from their diet, there are some cases where supplements can be beneficial. For example, it becomes harder to absorb B12 as you age, and it can be tricky to get enough if you're vegan, or don't eat much meat, eggs or dairy.

We've reviewed vitamin B12 supplements from a range of popular brands, including Boots, BetterYou, Dr Vegan, Holland & Barrett and Solgar to uncover the best options. Some contain far more than you need, while others are in formats that aren't well absorbed, or contain too many unnecessary additives. 

Why you can trust our Vitamin B12 supplement reviews

At Which? our reviews are completely independent and unbiased. We buy everything we test, looking at a range of prices and types to accommodate different budgets and needs.

Every supplement we review is analysed by me – Which?'s lead health and wellbeing researcher, Shefalee Loth, a public health nutritionist, along with consultant dietitian Sophie Medlin.

We both have decades of experience in this space. Sophie has advised on supplement development, and I have been scrutinising supplements for Which? for more than 10 years.

We've spent many hours reviewing the available evidence to determine optimal vitamin B12 supplement formats and dosages - as well as the less desirable additives - and assessing popular products against this rigorous evidence framework. 

The best vitamin B12 supplements

Only logged-in Which? members can view our full vitamin B12 supplement reviews and scoring, including the top-rated products.

Join Which? today to get instant access to our test results and Best Buy recommendations below, as well as revealing our Great Value picks.

The vitamin B12 supplements we assessed

A selection of popular vitamin B12 supplements included in our assessment are listed in alphabetical order below.

Only logged-in Which? members can view our full verdict on each. Join Which? to get instant access to our test results and recommendations.

Asda Vitamin B12 100mcg

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Available from Asda (£1.60 for 30)

Cost per daily dose 5p

Alpha01 Vitamin B12 drops 5000mcg

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Available from Alpha01 (£9.99 for 60ml) 

Cost per daily dose 17p

BetterYou B12 Boost 1200mcg

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Available from BetterYou (£12.49 for 25ml), Boots (£12.60 for 25ml), Holland & Barrett (£12.49 for 25ml)

Cost per daily dose 26p

Boots High Strength Vitamin B12 250mcg

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Available from Boots (£6.50 for 60)

Cost per daily dose 11p

Dr Vegan Vitamin B12 2000mcg

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Available from Amazon (£9.99 for 30), Dr.Vegan (£9.99 for 30), Superdrug (£9.99 for 30)

Cost per daily dose 33p

Natures Aid Vitamin B12 1000mcg

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Available from Amazon (£10.99 for 90), Natures Aid (£15.99 for 180), Ocado (£8.65 for 90)

Cost per daily dose 9p

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Nutravita Vitamin B12 1000mcg

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Available from Amazon (£9.99 for 365), Nutravita (£9.99 for 365), Superdrug (£9.99 for 365)

Cost per daily dose 3p

Nutrition Geeks Vitamin B12 Dual Power

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Available from Amazon (£13.99 for 365), Nutrition Geeks (£9.99 for 365), 

Cost per daily dose 3p

Solgar Vitamin B12 Sublingual Chewable Nuggets 1000mcg

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Available from Boots (£17 for 100), Holland & Barrett (£20.17 for 100), Solgar (£20.17 for 100)

Cost per daily Dose 20p

Superdrug Vitamin B12 10mcg

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Available from Superdrug (2.99 for 60)

Cost per daily dose 5p

Zipvit Vitamin B12 1100mcg

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Available from Amazon (£8.49 for 360), Zipvit (£7.49 for 360)

Cost per daily dose 2p

Note Cost per serving is based on the manufacturer's recommended serving size and the RRP (recommended retail price); however, some products are frequently discounted. We're not able to show every retailer, and cheaper prices may be available.

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More vitamin B12 supplement reviews

The rest of the vitamin B12 supplements we tested are listed below in alphabetical order.

Only logged-in Which? members can view our full iron supplement test results. Join Which? to get instant access today.

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How we review vitamin B12 supplements

Our nutritionist and dietitian supplement experts delve deep into the available research to determine optimal dose, absorption method and other key considerations when choosing a B12 supplement, before devising a scoring framework and rating each supplement based on what it contains. 

Our scores are based on:

• Bioavailability What form of vitamin B12 is used and what the science says about how well it's absorbed. Some types are ready to go, while others need conversion by the body into usable formats.

• Dose Does the supplement contain a safe and appropriate dose level? We consider recommended intake, safe upper limits, and how much your body is actually able to absorb. 

• Additives Other than active ingredients, what else does the supplement contain and is it necessary or simply filler? Sometimes bulking agents are necessary to make a usable size and shape of tablet, but we also check they are inert or non-concerning additions. 

We also make a note of the size and shape of the tablet or capsule, and alert you to any that are particularly large or small.

Lab checks: we send the top-scoring supplements to an independent lab for testing to make sure they contain the amount of vitamin B12 claimed on the label. Only those that pass this testing make it to a Which? Best Buy recommendation. 

Supplements that do well in our testing, and are also significantly cheaper than others, on test are labelled as Great Value, so you know the best budget options at a glance.

Why you can trust us: at Which? we're free from manufacturer and retailer influence. Find out more about our impartiality and how your support helps us to stay editorially independent

How and when to take vitamin B12 supplements

Ideally, you should take vitamin B12 supplements in the morning. This is because it's important for energy metabolism and taking it in the morning aligns with your body's need for energy throughout the day.

Some people find taking it in the evening or at bedtime interferes with their sleep. 

Vitamin B12 is a water-soluble vitamin, so it doesn't need to be taken with food. Ideally, take it on an empty stomach to allow for faster absorption and not at the same time as other supplements or medications.

How much vitamin B12 do you need?

The Nutrient Reference Value (NRV) for adults aged 19-64 is 2.5mcg a day. This is what's used on supplement labelling, where the vitamin B12 content is given in mcg and as a percentage of the NRV. 

However, the supplements in our assessment, which are based on a snapshot of the most popular and widely available retail options, contain between 3.6-5,000mcg. 

While there is no safe upper limit (because B12 is water soluble so you pee out anything you don't need), the NHS advises people not to take too much as it could be harmful. It says taking 2mg a day or less is unlikely to cause harm. 

The body can only absorb a small amount of vitamin B12 at one time anyway. In fact as dose increases, the efficiency of absorption decreases. 

This is why we've penalised supplements that contain doses above 100mcg. 

One side effect of high dose vitamin B12 is your urine changing colour to bright/neon yellow.

Very high doses of 5mg (5,000mcg) or more can cause skin issues such as acne or rosacea flare-ups and, in the case of methylcobalamin specifically, anxiety and jitters.  

If your vitamin B12 deficiency is caused by a condition or medication that affects absorption, or your levels are very low, your GP may prescribe a course of vitamin B12 injections. 

Best magnesium supplements – get our expert picks for magnesium, plus advice on the best type to buy

What does vitamin B12 do?

Vitamin B12 is needed to keep the nervous system healthy and is a key component in the upkeep of the insulating myelin sheath that coats our nerve cells.

It is also vital for red blood cell health, energy production and DNA replication and repair and has a role to play in breaking down the amino acid homocysteine, high levels of which have been linked to an increased risk of heart disease, stroke and dementia.

Symptoms of vitamin B12 deficiency

According to the NHS, low B12 levels can cause a range of symptoms, including those that affect your brain and nervous system, such as confusion and memory issues. These include:

• pale or jaundiced skin
• extreme tiredness and lack of energy
• recurrent mouth ulcers and sores in the corners of mouth
• cognitive issues such as anxiety, depression, 'brain fog' and paranoia 
• pins and needles, muscle weakness, cramping, impaired balance
• red, inflamed tongue
• blurred vision.

Who is most at risk of vitamin B12 deficiency and why?

Certain people are more prone to having low B12 levels than others. These are:

Older people

Vitamin B12 deficiency is more common in older people, affecting around 1 in 20 people aged 65-74 and 1 in 10 over the age of 75.

As we age, our levels of stomach acid start to decline, and these reduced levels can make it harder for B12 to be absorbed from food.

In older people, B12 deficiency can sometimes be confused with symptoms of dementia, which is why it's always worth getting checked out if you have symptoms.

Vegans 

Research shows that vegans are at higher risk of vitamin B12 deficiency. The British Nutrition Foundation recommends vegans eat fortified foods as well as considering a B12 supplement to make up any shortfall. 

You can find out more about the vitamins and minerals that are harder to get from a plant-based diet in our guide to nutrient deficiencies vegans need to watch out for.

If you take medications that may impact B12 levels

• Proton pump inhibitors (PPIs). Used by nearly a quarter of adults globally, medicines such as omeprazole are used to reduce stomach acid levels, but consistent use for 12 months or more can lower B12 absorption.
• H2-blockers. Also known as histamine H2-receptor antagonists (H2RAs), these are used to treat duodenal ulcers and gastric ulcers and can reduce circulating B12 concentrations with prolonged use.
• Anticonvulsants/anti-seizure medication. For example, phenobarbital, pregabalin, primidone and topiramate.
• Metformin. Used for type 2 diabetes, this is known to block B12 absorption and the MHRA (Medicines and Healthcare Products Regulatory Agency) suggests that the B12 levels of metformin users should be monitored if they develop deficiency symptoms.

If you're on any of these medications and think you have symptoms of B12 deficiency, speak to your pharmacist or GP for advice.

Certain health conditions and diseases

People with coeliac disease and Crohn's disease are unable to absorb vitamin B12. They are at higher risk of deficiency and should have their B12 levels monitored. If necessary your GP will prescribe intramuscular injections. 

Pernicious anaemia (not to be confused with iron deficiency anaemia) is an autoimmune disease that prevents your body from absorbing B12 and is the most common cause of vitamin B12 deficiency in the UK.

Bowel surgery patients

People who've had gastric or bariatric surgery, or who have an ileostomy, are commonly unable to absorb enough vitamin B12 from their diet or a supplement so are likely to need injections via their GP.

Are sprays or drops better than tablets?

Some of the supplements we've looked at are sprays, drops and sublingual nuggets that dissolve under the tongue. These are often promoted as preferable to traditional tablets as they claim to bypass the digestive system.

However, the reality is more nuanced than that and the research isn't conclusive. Clinical research shows that while some vitamin B12 is absorbed directly into the bloodstream via membranes in the mouth, much of the dose is still swallowed with saliva and absorbed in the same way as a tablet. 

If you have trouble swallowing pills, a sublingual vitamin B12 supplement or vitamin drop can be effective and convenient option, but otherwise you don't need to pay more. 

Research also shows there is no difference in the effectiveness of oral, sublingual and intramuscular supplements in raising blood vitamin B12 levels.

Should you have a vitamin B12 injection?

No, unless prescribed by your GP. 

Increasingly shops and clinics on the high street offer vitamin B12 (and other) injections often via IV drips as 'wellness boosts'. There is no benefit to these over traditional supplements and you're at risk of excessive B12 levels and other possible risks such as infection. Find out more in our story on why IV vitamin drips are a waste of money.

How to find out if you have low vitamin B12

It's important to see your GP if you have concerns. You should be able to access a test for free on the NHS if you qualify for NHS care. Your GP can check for B12 deficiency by carrying out a blood test and looking at your symptoms and medical history. 

NICE guidelines say you should be offered a test if you have at least one symptom or sign and one or more risk factors for the condition.

It is possible to buy a private vitamin B12 self-test, which will either be in the form of blood being taken by a professional or as finger-prick blood sample to do yourself via post. These typically cost from around £35 upwards. 

However, we have concerns about self-test kits not giving the full picture, and it is generally best to talk to your GP first.

If you do opt for a self-test, make sure you check for the following:

• Check the test covers 'active B12' (the amount available for your body to use) rather than 'total B12' levels
• Check the blood testing laboratories used to test them are accredited by UKAS.
• A health professional will interpret/advise on the results.

Best multivitamin supplements – in need of an all-rounder? See which products our experts rated best for 23 essential nutrients

Best food sources of vitamin B12

If you eat a varied and balanced diet that includes foods of animal origin you should be able to get all the vitamin B12 you need.

Vitamin B12 is found in animal products including meat, fish, milk, cheese and eggs plus fortified foods such as some breakfast cereals and plant milks.

Our supplement experts

We're no strangers to analysing supplements to uncover the best. We've spent the past year poring over ingredients lists and the latest clinical evidence, as well as asking brands for the data to support their claims, so that we can uncover the best supplements you can buy.

Other supplements recently reviewed include the best protein powders, creatine supplements, probiotic supplements and vitamin D supplements. Here's a bit more about us and our backgrounds:

Shefalee Loth, Which? principal researcher and nutritionist

Shefalee is a public health nutritionist with 20 years' experience, and has worked for the NHS, The London School of Hygiene & Tropical Medicine and World Cancer Research Fund.

At Which?, Shefalee is a principal researcher, researching and writing food and nutrition content for our magazine and website, and overseeing all our supplement reviews. She is also a media spokesperson and the research lead for our health and wellbeing reviews. She was previously a trustee at Sustain, the food and farming alliance and The Caroline Walker Trust.

Shefalee focuses on cutting through the hype to explain what you need to know about nutrition and healthy eating. From 'How bad is ultra-processed food?' to the 'Top gut health myths you need to know about' and 'What really works to cut cholesterol', she gives no-nonsense advice to help you make healthier choices and save money.

Sophie Medlin, consultant dietitian and founder of CityDietitians

Sophie Medlin is a well-recognised consultant dietitian with nearly 20 years' experience working across the NHS and academia and within her own private practice at CityDietitians. 

Sophie is chair of the British Dietetic Association for London.

With her in-depth knowledge of nutrition – both theoretical and applied – Sophie has helped to formulate supplements, giving her insight into the strengths and weaknesses of products and the manufacturing process.