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Do Vitamin B12 Shots Have Benefits?

For most of us, vitamin B12 injections have little to no value. While there is ample evidence that B12, as an essential vitamin, has numerous health benefits, there is no evidence that B12 shots have greater benefit than a B12 supplement in pill form. Further, even though B12 shots are a good way to remedy B12 deficiency in susceptible people, studies show that B12 supplements do just as good of a job. 1

Alcohol reduces vitamin B12 levels

While there are a number of studies linking alcoholism to severe B vitamin deficiency, the Journal Nature published a study in 2004 that looked at the impact of moderate alcohol intake on B12 levels in post-menopausal women. The study found no impact on folate levels, but reported a 5% reduction in serum B12 levels when women went from 0 to 30 g of alcohol a day. For reference, one standard drink contains 14 g of alcohol, so having a couple drinks a day can have a cumulative impact on vitamin B12.

See also: Does MTHFR affect the metabolism of all B vitamins? 

Vitamin B12 shot basics

So, as you can probably tell from the way I began the post, I am not a big fan of B12 injections and don’t use them in my practice. However, unfortunately, vitamin B12 deficiency is somewhat common, especially in the elderly, strict vegans, and people on antacid medications, so I don’t mean to downplay the importance of vitamin B12 or the B vitamins more generally. But does this mean that B12 shots, in which a nurse injects a vile of B12 into your hip or buttocks, is a good solution to this growing problem? In most people, a good quality B vitamin supplement, and not a shot, is probably the best solution.

Where is the B12 injected?

Typically, a B12 shot is administered in the upper buttocks, but some nurses will also use the shoulder. The nurse will place a band-aid over the injection site and send you on your way. While you wouldn’t describe a B12 shot as painful, they can make your hip sore for a few hours after you leave the pharmacy or doctor’s office.

How much do B12 shots cost?

Prices for a B12 injection can vary by location and practitioner. CVS Pharmacy lists B12 shots for $35 on its price list.

How much B12 is in a shot?

According to Ali Kalenak, a registered nurse and founder of Remedie Hydration Therapy in Jackson, Wyoming, most B12 shots come in 1,000 mcg doses. By contrast, most vitamin B12 supplements come in 600 mcg doses, which is 25,000% of the daily requirement.

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What is the best type of B12 for a shot?

Nurse Kalenak prefers either methylcobalamin or hydroxocobalamin, rather than cyanocobalamin. Why? Because methylcobalamin is easier to absorb than other forms of B12, which require a conversion step prior to absorption.

Common B12 injection side effects

The most common side effect after receiving B12 shots is a strange taste in the mouth. Note: this is not the same as having a metallic taste in your mouth, which can be a sign of vitamin B12 deficiency. According to WebMD, The more common B12 injection side effects are:

  • Swelling at the injection site
  • Mild dirhhea
  • Itching
  • Swelling in the body
  • Low potassium (weakness, irregular heartbeat)

There is a case report of an anaphylactic reaction to a B12 injection in a 55 year old women receiving cyanocobalamin, but these reactions are thought to be rare.

The bottom line on B12 shots

Although I don’t see the need for vitamin B12 shots, they are largely safe when administered under the care of a qualified physician or nurse. However, there is no evidence that B12 injections confer any greater benefit than does a good quality B vitamin complex, even in cases of B vitamin deficiency. It’s also not clear that mega-doses of B vitamins are safe over the long haul, especially in certain populations. Due to the complicating factor of a shot and the extra cost, it seems the best route for most people is to focus on getting adequate B vitamins from food, and supplement as necessary.

Dr. Aaron Gardner, BSc, MRes, PhD

Dr. Aaron Gardner, BSc, MRes, PhD is a life-scientist with a strong background in genetics and medical research, and the developing fields of personalized medicine and nutrition. Read his full bio here.

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