Nothing is impossible, but experiencing a Vitamin B12 overdose is improbable, to say the least.
Let’s get this out of the way first: Vitamin B12 (cobalamin) is, for the vast majority of people, safe in higher doses. Vitamin B12 is water-soluble, which means that any excess is passed through the body as waste, making a Vitamin B12 overdose difficult to achieve. Our bodies can’t store it, so collecting the requisite amount in our systems to be dangerous is pretty much impossible by traditional oral supplementation.
That said, everyone’s genetic makeup is different (we’re all snowflakes, right?), so some people may experience B12 side effects when taking large doses, which could be considered a Vitamin B12 overdose. And when we say large doses, we mean large doses administered by injection directly into the blood or muscles, not taken in a pill. Below are some possible side effects of a large B12 dose by injection:
- Dizziness
- Headache
- Anxiety
- Nausea
- Vomiting
- Hives
- Increased sweating
- Irregular heartbeat
There have also been reports of Vitamin B12 allergies, but these are extremely rare and multiple studies have indicated that they can be reversed through treatment with the cyanocobalamin form of B12. Some cases of acne have been reported, but it is likely due to an allergic reaction to cobalt, the central atom in B12.
Can I Take Too Much Vitamin B12?
Due to the challenges our bodies have in absorbing water-soluble vitamins, it is extremely difficult to take too much Vitamin B12. According to the National Institutes of Health Office of Dietary Supplements, the recommended allowance is a measly 2.4 mcg per day for people over 14 years old. You can get all of that from a single serving of fortified breakfast cereal.
Sort of.
You may consume 100% of your daily allowance of Vitamin B12, but that doesn’t mean that your cells are absorbing all of it. According to a 2008 study on Vitamin B12 deficiency, healthy people with normal absorption only absorb 56% of doses they consume orally.
Because of its low potential for toxicity, no tolerable upper intake level has been established for Vitamin B12. And the National Academy of Medicine has stated that “no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals”.
Certain populations are even advised to take supplements as they are so far from a Vitamin B12 overdose that they border on deficiency. As Vitamin B12 is almost exclusively found in animal products, strict vegetarians and vegans are at high risk of deficiency. Certain conditions that are common in older adults interfere with the ability to absorb Vitamin B12, leaving the elderly vulnerable as well.
B12 Medication Interactions
If you are taking any of the following medications, talk to your doctor before supplementing with Vitamin B12 as they have the potential for interfering with your body’s ability to absorb B12. There has been no evidence that taking these medications causes B12 toxicity. It’s the opposite actually, as these medications may decrease your absorption of B12 and thus lessen your already slim chance of a B12 overdose.
- Chloramphenicol
- Proton pump inhibitors
- H2 receptor antagonists
- Metformin
- Aminosalicylic acid
What Happens If I Somehow Manage to Have a Vitamin B12 Overdose?
If you’re experiencing any of the possible B12 side effects, contact your physician right away. Your symptoms could be the rare Vitamin B12 overdose (if you have been injecting the vitamin), or they could be indicative of an unrelated reaction. Regardless of its origin, the aforementioned symptoms warrant a visit to your doctor.
A B-12 overdose is rare due to the vitamin’s water solubility. In fact, we formulated our Lypo-Spheric® B Complex Plus supplement to maximize absorption of the B vitamins, including B-12. By encapsulating several vitamins in the B family in liposomes (fat capsules made of the same materials that comprise our cells), our Lypo-Spheric® B Complex Plus bypasses the absorption barriers in the digestive system and maximizes absorption. Lypo-Spheric® liposomal delivery enables more Vitamin B-12 to get to your cells where it is needed to support metabolic functions.
