Can You Take Too Much Vitamin B12?

Vitamin B12, also known as cobalamin, is essential for healthy cognitive function, red blood cell health, energy, mental health, healthy pregnancy outcomes, and more.

Although most people get enough Vitamin B12 from foods, deficiencies and insufficiencies can be common, especially in certain age groups and demographics.

For this reason, many people choose to take a Vitamin B12 supplement.

Choosing the right B12 supplement can be confusing, as many brands offer doses higher than the recommended daily allowance (RDA).

So, can you get too much vitamin B12 from foods, supplements, and/or injections, or is more B12 better for preventing deficiencies?

This article will answer all these questions, plus review the basics of B12, including how to know if you’re deficient, symptoms of deficiency and who's at risk of deficiency, how much B12 you need, how to treat excess B12, the best forms, and more.

Why Take A B12 Supplement?

People take vitamin B12 supplements for various reasons, including:

• To compensate for an existing deficiency or insufficiency
• During pregnancy
• Because they have a genetic variation that impairs B12 absorption from foods
• For energy
• Because they are taking certain medications that impair their ability to absorb B12
• Because they have gut health issues and suspect or have confirmed they are not absorbing enough vitamin B12
• To improve mental/emotional well-being
• For hair, skin, or nail health
• Because they are vegan or vegetarian and may not get enough Vitamin B12 from food. B12 is found primarily in animal-based foods like meat, dairy, and eggs

The best source of vitamin B12 is a healthy and diverse diet with a balanced amount of meats, dairy, eggs, and/or vitamin B12-fortified foods.

However, supplementation, even larger amounts than the RDA, can help compensate for any dietary insufficiencies.

Supplementation is also generally recommended for vegans, vegetarians, people over 50, people with genetic variations, and those taking certain medications like proton pump inhibitors and others we’ll discuss in subsequent sections.

How Do I Know If I’m Deficient In Vitamin B12?

Vitamin B12 deficiency often goes unnoticed until symptoms become severe.

Some symptoms of vitamin B12 deficiency include:

• Cognitive health issues, including poor memory and brain fog
• Depression, anxiety, personality disorders, or mood swings
• Digestive problems, such as diarrhea
• Frequent colds or compromised immunity
• Fatigue, mild, moderate, or extreme
• Premature gray hair
• Pregnancy issues
• Muscle cramping or weakness
• Brittle nails
• Nervous system issues

Discover 14 more symptoms of B12 deficiency in: Are You Deficient in Vitamin B12? 23 Benefits of B12 for Memory, Mood, Beauty, Energy, & More

Symptoms of B12 deficiency may also be mistaken for other conditions, so it’s important to insist on a B12 test if you suspect a deficiency.

Who is at Risk of a Vitamin B12 Deficiency?

Vitamin B12 deficiency used to be considered largely a vegan, vegetarian, or older person problem.

However, new research has shown that up to 26% of the global population is deficient in B12, suggesting this is not just an issue of diet or age.

There are many risk factors for vitamin B12 deficiency, some of which we discussed earlier, including:

• Age: Adults over 50 have higher rates of vitamin B12 deficiency.
• Certain pre-existing health conditions, such as Celiac, Crohn’s Disease, intestinal permeability, lack of hydrochloric acid, or thyroid conditions.
• Certain medications, such as birth control pills, diabetes medication, or proton pump inhibitors
• Genetic variations, such as MTHFR and others
• Pregnancy or lactation, which increases demands for vitamin B12.
• Vegans or vegetarians tend to lack vitamin B12 in their diets.

This is not an exhaustive list of all the risk or potential risk factors of vitamin B12 deficiency, but these are some of the most common.

How Much Vitamin B12 Do You Need?

Vitamin B12 needs can vary significantly from person to person based on previously discussed risk factors.

A simple blood test can determine whether your needs are being met. If they aren’t, it’s time to investigate.

The following are the recommended daily allowances from the NIH:

Can You Take Too Much Vitamin B12?

It is highly unlikely you’ll get too much B12 from foods, but what about supplements and injections?

Most people will experience no side effects from taking too much B12 from oral dietary supplements.

Why?

• Firstly, vitamin B12 is a water-soluble vitamin, which means the body naturally excretes what it doesn’t need through urine.
• Second, vitamin B12, especially certain forms of vitamin B12, is not readily absorbed from most supplements.

This is why some doctors and health experts recommend sublingual (dissolves under the tongue) pills or lozenges, liquid B12, or B12 or methylcobalamin, which are more readily absorbed. However, talk to your doctor about how much B12 you should be taking.

So, can you take too much B12 as an oral dietary supplement?

Yes, and many people do without realizing it (and wind up excreting their hard-earned money!).

The good news is that very few safety issues have been reported from taking B12, even in large doses.

You may experience side effects such as an upset stomach, nausea, or diarrhea, but these are not common.

Very rare side effects of mega-dosing oral B12 may include:

• Acne or red splotches on the face
• Anxiety
• Headache
• Insomnia
• Irritability
• Heart palpitations
• Tingling in hands and feet

Conversely, vitamin B12 injections can cause more serious side effects, including vomiting, congestive heart failure, and cancer, so contact your doctor immediately if you experience these after a B12 shot. Ideally, you shouldn’t be taking a B12 injection without consulting your doctor first.

Are There Long-Term Consequences of Taking Too Much B12?

Although there isn’t enough research to say for sure, one study from the Netherlands found that high levels of B12 in older people (over 50) resulted in greater overall mortality risk.

More research is needed, but it’s likely wise to keep your B12 levels optimal versus too high, especially if you’re over 50.

How to Treat Too Much B12

The only way to treat too much B12 is to cut back or discontinue supplementation and/or injections.

If you’re taking a multivitamin or other supplements such as those for hair, skin, and nails or workout recovery, you’ll want to check the amounts of B12 in those as well.

For individual recommendations, check with your doctor or healthcare practitioner.

Why Do Some Dietary Supplements Contain Such Large Doses of B12?

Vitamin B12 supplements contain a wide range of doses and forms of vitamin B12.

Some contain only the adult RDA, while others have mega-doses far beyond what’s considered necessary for baseline health.

There are many reasons a supplement may contain larger doses than the RDA, including:

• To help address deficiencies quickly
• To ensure maximum absorption (remember, B12 is poorly absorbed, so in theory, a larger dose may result in greater absorption)
• To support a specific aspect of health that may require larger doses
• The formula is designed for a group of people more susceptible to deficiency
• The formula is designed to address a specific health concern based on research

Taking more vitamin B12 than the RDA may benefit some people, but check with your doctor or healthcare practitioner for individual recommendations.

Best Forms of Vitamin B12

The most common form of vitamin B12 in supplements is cyanocobalamin, which works well for many people.

However, new research about genetic variations and the gut’s role in B12 metabolism has led many practitioners to recommend methylated forms of B12, such as methylcobalamin.

So, how do you know what’s best for you?

If you’re otherwise healthy and do not have a genetic mutation like MTHFR, then cyanocobalamin is generally recommended.

If you have a genetic mutation, gut health issues, or have had trouble restoring your B12 levels, methylcobalamin would be a better choice. It bypasses genetic mutations and is better absorbed in the gut.

There are also various delivery systems to consider, including:

• Capsules
• Lozenges or dissolvable tablets
• Gummies
• Liquids

The science of optimal delivery systems is not settled, but some evidence suggests lozenges or liquids may be better absorbed than capsules.

Check with your healthcare practitioner for individual recommendations.

Can You Get Too Much B12? Key Takeaways

We’ve covered a lot about vitamin B12 and dosage, so let’s recap.

Vitamin B12 is an essential nutrient predominantly found in animal-based foods like meats, dairy, and eggs. Deficiency affects about 26% of the global population and is not limited to vegans, vegetarians, or older adults. Risk factors for deficiency include age (over 50), pregnancy, certain medications, genetic variations, and specific health or autoimmune conditions. While oral B12 supplements are water-soluble and generally safe, injectable B12 can pose risks.

The form and dosage of B12 supplements vary, with some exceeding the RDA. These higher doses may be beneficial for some individuals depending on genetic and health factors, but they may not suit everyone. If you're concerned about B12 deficiency, excess, or toxicity, consult your healthcare provider for personalized guidance.

Looking for the Best B12 Supplements?

Country Life has been formulating and manufacturing clean, gluten-free, non-GMO, vegan, Vitamin B12 supplements in our Certified Organic and Gluten-Free facilities for decades.

Since no one size fits all, we offer several B12 forms and delivery systems, including methylcobalamin and cyanocobalamin in capsules, lozenges, gummies, and as individual supplements or complex formulations, including:

• Coenzyme B-Complex with methylcobalamin
• B12 Gummies with cyanocobalamin in a delicious strawberry base
• Methyl B12 Lozenges, 1000 mcg with methylcobalamin in a tasty cherry base
• Methyl B12 Lozenges, 3000 mcg with methylcobalamin in a yummy berry flavor
• Methyl B12 Lozenges, 5000 mcg with methylcobalamin in a higher therapeutic dose
• Vitamin B12 500 mcg with Folate with cyanocobalamin

Shop All Country Life’s Vitamin B12 supplements here.

If you think you may benefit from supplemental B12, consult your healthcare practitioner for individual recommendations.

Learn More About the Benefits of B12 and B Vitamins in:

• Vitamin B12 Or B-Complex: Which Is Right For Me?
• Are You Deficient in Vitamin B12? 23 Benefits of B12 for Memory, Mood, Beauty, Energy, & More
• 7 Great Reasons To Take Vitamin B

Sources Mentioned In This Article:

• “Vitamin B12 Deficiency”. Nature Reviews Disease Primers.
• “Vitamin B12 Fact Sheet for Health Professionals”. National Institutes of Health Office for Dietary Supplements.
• “Correlation Between Vitamin B12 Deficiency and Autoimmune Thyroid Diseases”. Endocrine, Metabolic, and Immune Disorders Drug Targets.
• “Vitamin B12 Deficiency”. StatPearls. Internet.
• “Are you getting enough B12?” Harvard Health.
• “Vitamin B12 Deficiency”. StatPearls. Internet.
• “How Birth Control Pills Affect Your Nutritional Needs”. Scientific American.
• “Association between metformin dose and vitamin B12 deficiency in patients with type 2 diabetes”. Medicine (Baltimore).
• “Proton Pump Inhibitor and Histamine 2 Receptor Antagonist Use and Vitamin B12 Deficiency”. JAMA.
• “Genetic Variants Associated With Vitamin B12”. Harvard School of Public Health.
• “Toxicity induced by multiple high doses of vitamin B12 during pernicious anemia treatment: a case report”. Clinical Toxicology.
• Association of Plasma Concentration of Vitamin B12 With All-Cause Mortality in the General Population in the Netherlands. JAMA Netw Open.