Maybe you’ve felt a little sluggish lately, or more fatigued than usual. Supplementing with vitamin B12 may help give you the energy you need to power through your day. Vitamin B12 comes in a number of different forms, but vitamin B12 supplements are most commonly made from methylcobalamin and cyanocobalamin.
Read on to learn about the differences between methylcobalamin and cyanocobalamin, the benefits of each, how to supplement with vitamin B12, and more.
Why do you need B12?
Vitamin B12, also known as cobalamin, is a micronutrient that is only found in animal products and fortified grains. It is the only metal-containing vitamin. Your body needs it to make DNA, red blood cells, and convert carbohydrates and fat into energy.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257642/
Your body can’t make vitamin B12 — you need to get it from food or supplements.
- Beef and lamb
- Fortified breakfast cereals and fortified nutritional yeast
What’s the Difference Between Methylcobalamin and Cyanocobalamin?
Methylcobalamin is a natural form of vitamin B12 that you can obtain through supplements or food sources, like meat, dairy, and eggs.
Both methylcobalamin and cyanocobalamin are compounds that contain a central metal ion — cobalt.https://www.sciencedirect.com/science/article/pii/S0167488920302548
They differ in that cyanocobalamin relies on a cyanide molecule to convert to a bioavailable form of vitamin B12, while methylcobalamin has a molecule called a methyl group attached to it. Methylcobalamin provides a methyl group that breaks down the amino acid homocysteine, which at high levels can damage blood vessels and lead to heart disease and stroke.
Which one should you choose?
Cyanocobalamin is manmade, so it first needs to be converted to methylcobalamin in order for your body to absorb it. Unlike cyanocobalamin, methylcobalamin is naturally occurring and already bioavailable, so your body may absorb it more easily and quickly.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5312744/
One animal study found that urinary excretion of cyanocobalamin was three times higher than that of methylcobalamin. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5312744/ But, both cyanocobalamin and methylcobalamin can raise your B12 levels.
Cyanocobalamin contains trace amounts of cyanide – a toxic chemical – and some people worry that supplementing with it may cause cyanide to accumulate in tissues over time.https://pubmed.ncbi.nlm.nih.gov/18709891/ However, the amount of cyanide is likely too small to have any adverse effects, even with long-term use, and most of the cyanide is excreted through the urine.https://www.consumerlab.com/answers/is-the-cyanocobalamin-form-of-b-12-dangerous/cyanocobalamin-safety/
The Health Benefits of Methylcobalamin and Cyanocobalamin
Vitamin B12 Deficiency
Both methylcobalamin and cyanocobalamin can treat vitamin B12 deficiencies.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3875920/
Vitamin B12 deficiency is common, especially in vegetarians and vegans, those eating a limited amount of animal products, and in the elderly.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257642/ Older people are at a higher risk of developing a vitamin B12 deficiency due to gastritis, a condition common in the elderly that inflames the stomach lining. Gastritis lowers stomach acid, which is needed to separate vitamin B12 from protein so that the body can absorb it.http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.186.5217&rep=rep1&type=pdf
Other risk factors of vitamin B12 deficiency include:
- Long term use of certain medications, such as metformin or proton pump inhibitors
- Gut disorders, such as Crohn’s diseases, inflammatory bowel disease or celiac diseasehttps://pubmed.ncbi.nlm.nih.gov/24091055/https://pubmed.ncbi.nlm.nih.gov/17886286/https://pubmed.ncbi.nlm.nih.gov/11280545/
- Weight loss surgery, which destroys cells that produce intrinsic factor, the protein necessary for vitamin B12 absorption.
- MTHFR (methylenetetrahydrofolate reductase) mutation, which lowers your body’s ability to break down vitamin B12.
- Pernicious anemia— an autoimmune disease that lowers intrinsic factorhttps://pubmed.ncbi.nlm.nih.gov/28660890/
- Glossitis (a swelling of the tongue)
- Weight loss
- Neurological problemshttps://pubmed.ncbi.nlm.nih.gov/22221769/
Even if you aren’t deficient in vitamin B12, supplementing with methylcobalamin or cyanocobalamin could have some health benefits, including increased energy and improved mental function. A 2010 study found that 10 micrograms of vitamin B12 per day improved mood, lowered stress, and reduced mental fatigue.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2885294/
Vitamin B12 Dosage
The recommended daily dosage is 2.4 mcg of vitamin B12 a day, and more if you’re pregnant (2.6 mcg) or breastfeeding (2.8 mcg).https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
Vitamin B12 multivitamins typically contain large amounts of vitamin B12 — between 5 and 25 mcg.
Vitamin B12 can be consumed in capsule, tablet, or lozenge form. It’s best taken in the morning, with or without food, since vitamin B12 can have an energizing effect.
You can also use vitamin B12 as a nasal spray. The absorption rate is similar to when taken orally.https://pubmed.ncbi.nlm.nih.gov/25031664/ The advantage of a nasal spray is you typically only need to use it once a week, versus one or more times a day when in supplement form. Nasal sprays use either methylcobalamin or cyanocobalamin.
Vitamin B12 injection
To treat a vitamin B12 deficiency, a doctor might prescribe a vitamin B12 injection. The forms of vitamin B12 used in injections are typically cyanocobalamin or hydroxocobalamin (also synthetic).
Vitamin B12 shots bypass the digestive system and get directly absorbed by the bloodstream.https://www.nejm.org/doi/10.1056/NEJMc1304350 Vitamin B12 shots have risen in popularity in recent years for those without a deficiency to increase energy and manage weight, although more research is needed to support these claims.
How frequently you get a vitamin B12 shot depends on how deficient you are and what your doctor deems appropriate. The doctor or nurse will inject it into your muscles, usually the buttocks, thigh, or upper arm.
Although vitamin B12 injections are generally considered to be safe, it’s a good idea to check with your doctor or medical practitioner before getting one. Many pharmacies require a doctor’s prescription to administer a vitamin B12 shot.
Common side effects of the shot include pain or redness at the injection site, mild diarrhea, and nausea.
If you’d rather avoid needles, studies show oral supplementation of vitamin B12 is likely as effective as injecting it into the muscle.https://pubmed.ncbi.nlm.nih.gov/24522672/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC554115/
Vitamin B12 Safety
Supplementing with B12 is therefore generally considered safe. It also means that taking high doses of it likely won’t increase its positive effects, since your body will simply get rid of what it doesn’t need.
As always, check with your doctor to determine the best course of treatment.