The 8 Best B12 Supplements of 2023, According to a Dietitian

Are B12 Supplements Beneficial?

B12 supplements are helpful in treating and preventing those with a deficiency. The following groups of people are at risk for deficiency, and may benefit from a supplement. 

• Vegans and Vegetarians. “Many vegans and vegetarian eaters don’t take in enough vitamin B12. This is because many sources are animal based, and the nutrient isn’t always easy to get enough of on a plant-based diet,” says plant-based dietitian Amy Gorin.
• Older Adults. People over the age of 65 may have lower levels of stomach acid, which is required to break down and absorb B12. If there is not enough stomach acid, the B12 cannot combine with intrinsic factor in the stomach, and this step is needed to absorb B12 in the small intestine.
• People with certain digestive disorders or illnesses. People with digestive disorders affecting the stomach and small intestine such as Crohn’s, small intestinal bacterial overgrowth (SIBO), H.Pylori, and Celiac disease may not be able to properly absorb B12.
•  People who have had bariatric surgery. Bariatric surgeries such as the roux-en-y gastric bypass put patients at risk for B12 (among other nutrient) deficiency. This is related to lower intrinsic factor production, lower stomach acid, and bypassing a part of the small intestine called the duodenum, which is the main site of B12 absorption.
• People taking certain medications. Some medications, especially those aimed to treat gastroesophageal reflux disease (GERD), reduce stomach acid content which can increase risk for B12 deficiency. Metformin, a common diabetes medication, is also associated with B12 deficiency. 
• People who have a variant of the MTHFR gene: “People who have a variant of the MTHFR gene mutation might need to take B12, since this gene mutation interferes with the body's natural ability to use certain B vitamins including B12,” says Jenna Volpe.
• People with HIV. Studies suggest that up to 10 percent of people with HIV are deficient in B12. If you have HIV, have your B12 levels checked and discuss with a healthcare professional to see if you could benefit from a supplement.

Who May Not Benefit from a B12 Supplement

In general, B12 supplements are safe for most people. Vitamin B12 is water soluble, which means that your body will excrete what it doesn’t need through urine. However, many people don’t need a B12 supplement and consuming excess B12 does not provide any additional benefits.

The following types of people may not benefit from taking a B12 supplement:

• People that regularly eat animal protein. The best food sources of B12 include meat, fish, poultry, eggs, and milk. If you regularly consume these foods, you should be getting enough through your diet.
• People taking certain medications. Both gastric acid inhibitors (medications to treat GERD) and Metformin (used to treat diabetes) may reduce the body’s ability to absorb vitamin B12, including from certain supplements. If you take these medications and are deficient in B12, you may need to consider a sublingual supplement or talk to a healthcare provider about B12 injections.
• People with a sensitivity to cobalt. Cobalt is present in cyanocobalamin, the most common form of B12 supplements. If you have a known cobalt allergy, it’s recommended you take a different form of B12 like methylcobalamin.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here. 

We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products. We prioritize products that are third-party tested and certified by one of three independent, third-party certifiers: USP, NSF, or ConsumerLab.com. 

It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend. We also consulted with the following registered dietitians:

• Amanda Lane, MS, RDN, CDCES, dietitian specializing in dialysis at Plant-Powered Kidneys Renal Nutrition Services
• Jenna Volpe, RDN, LD, CLT, functional dietitian and founder of Whole-istic Living
• Amy Gorin, MS, RDN, inclusive plant-based dietitian and owner of Plant Based with Amy

What to Look For

Third-Party Testing 

Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:

• Third party testing does not test to see if a product is effective or safe for everyone, and it does not ensure the supplement will not interact with other supplements or medications.
• Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing. 
• The third party certifications we can trust are: ConsumerLab.com, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations. 
• Sometimes products tested by these three companies are more expensive to try to offset the cost they pay for certification.
• Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and their testing lab to determine their protocols and decide if you feel comfortable consuming the supplement.

Form 

There are four different forms of vitamin B12: cyanocobalamin, methylcobalamin, adenosylcobalamin, and hydroxocobalamin. Methylcobalamin and adenosylcobalamin are active forms of vitamin B12 whereas the others require the body to convert it to the active form.  According to the National Institutes for Health, there is no evidence to suggest that absorption rates vary significantly between forms. Recent research comparing the two most common forms (methylcobalamin and cyanocobalamin) is limited.

Vitamin B12 supplements are available in capsule, sublingual, chewable, liquid, spray and injection (a high dose requiring a prescription from a healthcare provider). The best form for you will depend on the reason for deficiency.

“People who are dealing with low B12 levels due to poor stomach acid absorption may benefit most from a B12 shot or sublingual version of a B12 supplement, since these delivery methods bypass the gut,” says Volpe. She adds, “You'll start absorbing it in your mouth instead of waiting for it to be activated by your stomach acid and released through your small intestine—which may not be working effectively."

Vitamin B12 is also found in combination with other B-vitamins as well as in multivitamins and prenatal vitamins. “When there are multiple B vitamin deficiencies or other vitamin or mineral deficiencies uncovered, I typically recommend seeking out a B complex or multivitamin or prenatal containing methylated B12 versus just taking a B12 supplement,” says Volpe.

Ingredients & Potential Interactions

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included, relative to the recommended daily value of that ingredient. Please bring the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.

If you’re taking vitamin B12 as part of a B-complex or multivitamin, always check with your healthcare provider to ensure the other ingredients are safe for you as they may contain ingredients that can interact with medications or other supplements you take.

Vitamin B12 Dosage 

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and to understand which dosage to take. 

The Recommended Daily Allowance for adults for vitamin B12 is 2.4 micrograms. Pregnant and lactating people need 2.6 micrograms and 2.8 micrograms respectively. Most supplements come in much higher doses because the body can’t absorb everything consumed through supplements. The recommended dose for those with deficiency is 1,000 to 2,000 micrograms, especially to correct anemia or neurological symptoms. It’s also recommended that people who have had bariatric surgery take 1,000 micrograms daily.

It’s estimated that absorption rates for those containing less than 2 micrograms of vitamin B12 is about 50 percent. That significantly decreases with higher doses. Supplements with 500 micrograms of vitamin B12 are absorbed at about a 2 percent rate and 1,000 - 2,000 micrograms are absorbed at only 1.3 percent. That means if you take a supplement that contains 2,000 micrograms of vitamin B12, you’re likely absorbing about 26 micrograms. 

How Much is Too Much? 

There is currently no established tolerable upper limit (UL) for vitamin B12 as there is low risk of toxicity. Because it’s a water soluble vitamin, your body excretes what it doesn’t need in urine.