Is It Possible To Take Too Much B12?

Vitamins and minerals are essential for vitality, which may explain why vitamin supplements are a multibillion-dollar business., Among the plethora of supplements on the market, vitamin B12 ranks near the top of the popularity list. In fact, roughly a quarter of men and nearly a third of women take B12 in supplement form, according to the National Institutes of Health. This member of the B vitamin family is vital for red blood cell production, nerve and brain function, and cellular health. It’s also touted for its ability to help boost energy and mood.

But how much B12 do you need, and can you take too much of it? (Or do you even need to take it at all?) Most people get adequate amounts of B12 through food. However, a B12 supplement can help ensure you’re getting enough—especially if you’re vegan or vegetarian or if you struggle to absorb this essential nutrient.

Read on to learn who can benefit from a B12 supplement and if it’s possible to take too much of it.

What Is Vitamin B12?

Vitamin B12 (also called cobalamin) is a water-soluble vitamin that’s crucial for various bodily functions, including red blood cell formation, energy production, DNA synthesis and brain health. It is found naturally in animal products such as meat, dairy and eggs and is essential for maintaining healthy nerve cells and producing energy. B12 deficiency can lead to fatigue, weakness and neurological issues like numbness, tingling and cognitive impairment. Since your body stores B12 in the liver for extended periods, deficiency symptoms may only appear years after inadequate intake.

How Much Do You Need?

The Recommended Dietary Allowance for vitamin B12 varies by age, gender and life stage. According to the National Institutes of Health, most healthy adults require 2.4 micrograms daily, which is usually met through a balanced diet. Those who are pregnant or breastfeeding have slightly higher requirements at 2.6 and 2.8 micrograms per day, respectively. Vitamin B12 is absent from plant foods like fruits, vegetables, beans and grains. To meet needs, it’s necessary to consume animal products such as eggs, dairy and meat, or plant-based foods like nutritional yeast, fortified cereals and fortified plant-based milks.

Do You Need a B12 Supplement?

Most people can get enough of this nutrient through diet, but certain groups are at a higher risk of deficiency and may require supplementation.“People prone to B12 deficiencies include those who follow vegetarian and vegan eating patterns, because B12 is not found in plant foods, and older adults with decreased absorptive efficiency,” says Lauren Harris-Pincus, M.S., RDN, founder of NutritionStarringYou and author of The Everything Easy Pre-Diabetes Cookbook. Certain health conditions, such as pernicious anemia and gastrointestinal disorders that affect nutrient absorption, such as Crohn’s or celiac disease, may also increase the risk of vitamin B12 deficiency, she adds. Additionally, GI surgery and medications like metformin and proton pump inhibitors may also impair the absorption of this vitamin.

Can You Take Too Much Vitamin B12?

Since vitamin B12 is water-soluble, it has a low risk of toxicity. “The body typically excretes excess amounts of B12 through urine,” explains Trista Best, RD, a registered dietitian with Balance One Supplements. “However, taking very high doses of B12 supplements, especially over extended periods, can potentially lead to side effects. While the upper limit for B12 intake [has not been] established, avoid excessively high doses without medical supervision.”

Signs & Symptoms

Vitamin B12 is considered safe even at high doses since your body doesn’t store excess amounts. However, in rare cases, excessive B12 intake from supplements may cause unwanted side effects. Some studies suggest high B12 doses might impact kidney function or interact with certain medications. Another potential symptom of taking too much B12 includes mild skin reactions, such as itching, rashes or acne-like breakouts.

“Speak with a health care provider before significantly increasing your B12 intake, especially if you’re on medication or have underlying health conditions like chronic kidney disease,” says Best. “Regular blood work can also help ensure your B12 levels are within a healthy range.”

The Bottom Line

Vitamin B12 is a water-soluble nutrient essential for several bodily functions, including red blood cell production, nerve and brain function, mood and energy. Most healthy adults get enough B12 through food. However, some people may benefit from supplementing B12, including vegans, vegetarians, people taking certain medications, and those with chronic kidney disease. Because B12 absorption decreases with age, supplements may also be helpful for people over age 65.

Although B12 supplementation is generally safe even in high doses, monitoring your intake is wise to avoid potential side effects, such as skin conditions or kidney issues. Talk to your health care provider or a registered dietitian before increasing your B12 supplementation to help ensure you maintain optimal levels for excellent health.