Table of ContentsView AllTable of ContentsPrescribed B12Optional B12Side EffectsWhere to Get ThemHow Many to Get
Table of ContentsView All
View All
Table of Contents
Prescribed B12
Optional B12
Side Effects
Where to Get Them
How Many to Get
Vitamin B12 shots are primarily given to help with B12 deficiencies and may reduce the risk of developing certain health disorders, including neurological conditions and infertility.
Administered through an injection into a muscle,vitamin B12shots contain a synthetic version of B12, otherwise known as cyanocobalamin. Although even high dosages of vitamin B12 carry no risk of toxicity, its benefits lie in getting enough of the nutrient, not overdoing it.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. Whenchoosing a supplement, look for independently tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
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Prescribed B12 Shots: When Would a Provider Recommend Them?
Vitamin B12 is a water-soluble (dissolves in water) vitamin that ensures the optimal health of blood and nerve cells. It also lends a hand in making DNA and can help prevent certain health conditions, such asmegaloblastic anemia.
When people don’t get enough of the vitamin through diet, they are often recommended supplements. One such supplemental B12 known as a B12 shot is an injectable given intramuscularly (directly into the muscle).
The shots are typically reserved for people who do not get enough B12 in their diet or are deficient in the nutrient for various other reasons. Many factors can lead to aB12 deficiency, including:
When people fall into any of the categories mentioned above, they are more likely to develop a deficiency or are typically monitored for one so that they can be prescribed B12 shots if needed.
How to Tell If You Have a B12 DeficiencySince a B12 deficiency comes on gradually, the symptoms tend to have a slow onset. If you notice any of the following symptoms, you may benefit from having your levels checked:Numbness or tingling in the hands, legs, or feetIssues with balanceStaggered walkingAnemiaSwelling and inflammation of the tongueMemory lossDifficulty reasoning or thinkingWeakness and fatigue
How to Tell If You Have a B12 Deficiency
Since a B12 deficiency comes on gradually, the symptoms tend to have a slow onset. If you notice any of the following symptoms, you may benefit from having your levels checked:Numbness or tingling in the hands, legs, or feetIssues with balanceStaggered walkingAnemiaSwelling and inflammation of the tongueMemory lossDifficulty reasoning or thinkingWeakness and fatigue
Since a B12 deficiency comes on gradually, the symptoms tend to have a slow onset. If you notice any of the following symptoms, you may benefit from having your levels checked:
The 8 Best B12 Supplements, According to a Dietitian
Optional B12 Supplement Shots
In some cases, people may believe they can benefit from B12. They may request B12 shots even if their healthcare provider doesn’t detect a deficiency and doesn’t believe there’s a need for them.
Possible health benefits of getting regular B12 shots include:
It’s important to note that B12 hasno toxicity risk. Because of that, it can be taken in high amounts, even in people without a deficiency. However, that does not mean you should take more than you need.
Typically, a B12 deficiency leads to an increased risk of developing certain conditions, such as heart disease orhaving obesity.
B12 Shots Without a DeficiencyB12 is water-soluble, meaning that the body does not store it, and any excess amounts get flushed out of the body in the urine with other waste products. Because of that, if a person takes B12 shots but does not have a deficiency, it is more likely that the body will use what it needs and flush out the rest.
B12 Shots Without a Deficiency
B12 is water-soluble, meaning that the body does not store it, and any excess amounts get flushed out of the body in the urine with other waste products. Because of that, if a person takes B12 shots but does not have a deficiency, it is more likely that the body will use what it needs and flush out the rest.
The Best Sources of Vitamin B12 for Any Diet
Do B12 Injections Cause Side Effects?
While there is no upper limit when taking vitamin B12, the shots may pose some side effects in some people. Some adverse effects include:
In some cases, rare but more severe side effects can occur. Since a synthetic form of the vitamin is used, not everyone will tolerate it well. The severe possible side effects include:
When to Call 911 for a Serious Allergic ReactionSome symptoms may develop after a B12 shot that indicates you need emergency services right away. Those signs include:Swollen lips, mouth, tongue, or throatFeeling as though you can’t breathe or rapid breathingDifficulty swallowingBlue, gray, or pale lips, skin, or tongue. In those with darker skin tones, this will be more visible on the palms and soles of the feet.Feeling confused, drowsy or dizzyFainting and not being able to wake upIn children, becoming floppy or unresponsiveAn itchy, blistering rash
When to Call 911 for a Serious Allergic Reaction
Some symptoms may develop after a B12 shot that indicates you need emergency services right away. Those signs include:Swollen lips, mouth, tongue, or throatFeeling as though you can’t breathe or rapid breathingDifficulty swallowingBlue, gray, or pale lips, skin, or tongue. In those with darker skin tones, this will be more visible on the palms and soles of the feet.Feeling confused, drowsy or dizzyFainting and not being able to wake upIn children, becoming floppy or unresponsiveAn itchy, blistering rash
Some symptoms may develop after a B12 shot that indicates you need emergency services right away. Those signs include:
How Do You Know If You Have Allergies?
Where to Get B12 Shots
You can get B12 shots in one of two ways: through a healthcare provider or with at-home injections. While the safest way is through a healthcare provider, both can be done safely with the proper care and instructions.
Through a Provider
If you are prescribed B12 shots through a healthcare provider, they will likely develop a schedule for you to adhere to. You will visit their office at set times, and they will inject the vitamin there. They will then monitor you for anyadverse effects.
You must visit the healthcare provider’s office every other day for two weeks to receive the shots. Once symptoms start improving, your B12 levels will be monitored accordingly to see how many shots you need to continue getting the right amount of the vitamin.
Self-Injection
Self-injections of B12 can also be done. However, if you have not yet had a B12 shot, you should first speak to a healthcare provider and have them do the first one so that you know how you react to it.
Once it’s deemed safe for you to do at home, you will be given a prescription for B12 shots you can take at home, or you can purchase them from a trusted health organization.
You and a healthcare provider will go over a schedule for you to adhere to so that you aren’t injecting too much or too little B12, and they will also provide you with instructions on how to do it.
The injections are given into a muscle, typically the thigh. To do so safely, you must follow these steps:
Getting the Right B12 ShotsThe best B12 shots to get are the ones that your healthcare provider prescribes to you. Some health spas may also provide B12 shots, but you’ll want to ensure you get the best quality possible. Naturopaths and other licensed healthcare providers should be the only places you purchase B12 shots for at-home use.
Getting the Right B12 Shots
The best B12 shots to get are the ones that your healthcare provider prescribes to you. Some health spas may also provide B12 shots, but you’ll want to ensure you get the best quality possible. Naturopaths and other licensed healthcare providers should be the only places you purchase B12 shots for at-home use.
Dietary Supplements
How Many B12 Shots Will You Get?
The number of B12 shots a person needs will depend highly on their level of health andhow deficient they are in the vitamin.Typically, someone with a deficiency will have to take one B12 shot every other day for two weeks until reexamining their levels.
From there, a healthcare provider will determine if more is needed and how often they should be given, based on a person’s response to the shots and their level of deficiency.
Summary
Typically, a person with a severe deficiency will have to have B12 shots administered every other day for two weeks. This can be done at home or at a healthcare provider’s office. You should avoid getting B12 shots online or from another retailer until you speak to a healthcare provider and check your levels. Getting the shots from a trusted healthcare professional is the best route if you need them.
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Harvard Health Publishing Harvard Medical School.Vitamin B12 deficiency can be sneaky and harmful.
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Markun S, Gravestock I, Jäger L, Rosemann T, Pichierri G, Burgstaller JM.Effects of Vitamin B12 Supplementation on Cognitive Function, Depressive Symptoms, and Fatigue: A Systematic Review, Meta-Analysis, and Meta-Regression.Nutrients.2021 Mar 12;13(3):923. doi:10.3390/nu13030923
Pawlak R.Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians?Am J Prev Med.2015 Jun;48(6):e11-26. doi:10.1016/j.amepre.2015.02.009
Yahn GB, Abato JE, Jadavji NM.Role of vitamin B12 deficiency in ischemic stroke risk and outcome.Neural Regen Res.2021 Mar;16(3):470-474. doi:10.4103/1673-5374.291381
Banihani SA.Vitamin b12 and semen quality.Biomolecules.2017 Jun 9;7(2):42. doi:10.3390/biom7020042
UK National Health Service.Side effects of hydroxocobalamin.
UK National Health Service.Treatment vitamin B12 or folate deficiency anemia.
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