If you stay up-to-date on the latest medical trends, you may have heard of vitamin B12. Some people believe B12 improves energy levels or aids in weight loss. And some people claim that getting shots of vitamin B12 is essential to your health. But what’s the truth about B12 shots? Are they beneficial or harmful?
Read on to understand what vitamin B12 does and if vitamin injections are right for you. And of course, always speak to a medical professional before adding something new to your routine.
But first of all…
What are Vitamins?
Vitamins are compounds that are essential to your health and well-being. They’re not made in your body, but you can get them by eating and drinking the right things.
Some vitamins are fat-soluble, meaning they get stored in fat cells. Others are water-soluble. Whatever your body doesn’t use gets eliminated through your pee. Vitamin B12 is a water-soluble vitamin.
Usually, most vitamins are needed in small quantities. A balanced diet can be all you need to get enough vitamins.
What is Vitamin B12?
Vitamin B12 actually refers to an entire family of compounds. These compounds all contain cobalt, which is why vitamin B12 is also known as cobalamin. They’re all grouped together under the name vitamin B12.
Vitamin B12 is a water-soluble vitamin obtained from animal sources, such as:
- Grass-fed French or Italian meat or dairy
- Pasture-raised eggs
Bacteria are the only living organisms to produce vitamin B12. All other organisms get their vitamin B12 from their food. It’s also the only water-soluble vitamin stored in the liver, as opposed to being excreted in the urine.
What Does Vitamin B12 Do?
Your cells use vitamin B12 to release energy from carbohydrates, fats, and proteins. It helps to boost the levels of folate in your cells, helping them produce DNA. Vitamin B12 is also necessary for the normal formation of red blood cells and proteins in the body.
Vitamin B12 also helps maintain the protective covering around nerve cells, called a myelin sheath. It protects nerve fibers and keeps them separate from each other.
In general, your body uses what it needs from water-soluble vitamins and passes the excess through your pee. Vitamin B12 is different. Your liver can store this water-soluble vitamin for several years.

How is Vitamin B12 Absorbed by the Body?
Unlike other vitamins, vitamin B12 isn’t simply absorbed. There are several steps to the process.
- The first step to vitamin B12 absorption is separating the vitamin from the food protein it’s bound to. Stomach acid helps make that happen.
- The next step is binding the vitamin to a protein called intrinsic factor. This protein is also made in your stomach.
These two steps allow your small intestine to better absorb the B12.
Human digestion is a complex process. There are a few things that might go wrong in the absorption of vitamin B12.
- Your gastric juices may not be strong enough to separate the vitamin from food proteins.
- Your stomach may not produce enough intrinsic factor to absorb B12 well.
- Problems with the digestive tract can reduce how much B12 you absorb.
Any one of these issues can result in a vitamin B12 deficiency. This condition can lead to serious health complications, so if you suspect you may have a B12 deficiency, it is important to consult your doctor immediately.
Symptoms of a B12 Deficiency
Vitamin B12 is essential to make red blood cells and make sure the nervous system is functioning well. A deficiency in vitamin B12 can lead to serious health problems if not treated by a medical professional.
The early symptoms of vitamin B12 deficiency include:
- Fatigue
- Weakness
- Constipation
- Loss of appetite
- Swelling of the tongue
Symptoms may worsen as the B12 deficiency becomes more serious.
Am I Getting Enough Vitamin B12?
Sources of B12
The only living organisms that produce vitamin B12 are certain bacteria. Everything else along the food chain gets it through diet. Herbivores get vitamin B12 through their gut bacteria. Carnivores get enough vitamin B12 by eating those herbivores.
Ideal sources include most Gundry-approved animal products. Keep your daily intake of meat limited between 2-4 oz.

Remember, only pasture-raised poultry and grass-fed and finished meat. Seafood can also be a great source of vitamin B12. You may also be able to get vitamin B12 in Gundry-approved milk alternatives.
Now, there are few plant-based sources of vitamin B12. However, vegans and vegetarians may struggle to get enough vitamin B12 in their diets. If you’re concerned you are vitamin B12 deficient, talk with your doctor. You may need B12 shots to help you meet your B12 needs.
Am I Absorbing Enough B12?
Most adults and children in the U.S. meet their daily recommended intake for vitamin B12. Now, some people are at risk of vitamin B12 deficiency – even if they meet their dietary goals. These include:
- People with certain digestive disorders. They struggle to absorb adequate levels of vitamin B12 from food.
- People who have had gastrointestinal surgery. This group may not produce enough intrinsic factor or stomach acid to absorb B12.
- Older adults with less acid in their stomachs. Stomach acid helps separate vitamin B12 from food proteins. Adults over 50 may need vitamin B12 supplementation.
- Strict vegetarians and vegans. Fortified foods and nutritional yeasts are the only non-animal sources of vitamin B12. Amounts vary, so read labels carefully.
- Pregnant and lactating vegetarian women and their infants. During pregnancy, vitamin B12 passes to the infant through the placenta. After pregnancy, vitamin B12 is present in breast milk. If the mother has limited reserves of B12, she may run out of the vitamin within months. This is dangerous to the mother and baby. If you’re pregnant or nursing, talk with your doctor about B12 supplementation.
Medication Can Interfere with Vitamin B12 Absorption
Certain medications may interfere with your body’s ability to absorb vitamin B12. If you’re concerned about medication and a vitamin B12 deficiency, talk to your doctor.
Benefits of B12 Vitamin Supplementation
Types of Vitamin B12 Supplements
Vitamin B12 supplements come in three main forms:
- Oral supplements and fortified foods
- Intravenous drips
- Intramuscular shots
There are also four types of vitamin B12 that are available as a supplement. Different supplement types will use different types of vitamin B12.
Methylcobalamin
This form of vitamin B12 is most often used in oral supplements and some vitamin B12 shots. Methylcobalamin is the active form of cobalamin found in your body; helps maintain the myelin sheath of nerve fibers.

Methylcobalamin also works in the synthesis and repair of DNA, the synthesis of amino acids and proteins, and the production of red blood cells.
Cyanocobalamin
This artificial form of vitamin B12 popular in vitamin B12 shots and IV supplements. One reason why cyanocobalamin is a popular choice is because it’s more stable, thanks to an added cyanide molecule. The amounts present are minimal, produce no adverse effects, and the FDA has approved cyanocobalamin for human use.
Hydroxocobalamin
Hydroxocobalamin is mainly used in vitamin B12 injections. This type of B12 is lab-grown in bacterial cultures. It’s readily converted by the body into its active form.
Adenosylcobalamin
This active form of cobalamin is rarely used as a supplement due to the instability of the molecule.
Which Type of Vitamin B12 Delivery is Best?
Many studies have tried to determine which delivery method and type of B12 is best.
Researchers have gotten mixed results.
There may be differences that affect absorption rates. Some people will do better with oral supplements instead of intramuscular B12 shots. Others will thrive on shots, as opposed to oral supplements.
Talk to your doctor about what options might work best for you. That way, you’ll get a suitable amount of vitamin B12 to prevent deficiency and its effects.
Benefits of Vitamin B12 Supplements
Studies show B12 can increase energy levels in B12-deficient people with anemia. This is where B12 supplements shine. They’re made for people with vitamin B12 deficiency.
If you have a B12 deficiency, supplements (including B12 shots) may improve symptoms like:
- Fatigue
- Dizziness

Are B12 Shots Safe?
Studies have shown even mega-doses of vitamin B12 daily for years show no adverse effects. Your body tends to use what it needs and gets rid of the rest. Vitamin B12 shots are safe as long as they’re administered correctly. This doesn’t mean there aren’t any side effects. Mild side effects from B12 shots include:
- Nausea
- Headache
Rarer (and severe) side effects can include:
- Irregular heartbeat
- Cramps
- Breathing difficulties
Certain medical conditions can also interact with vitamin B12 shots. Individuals should consult with their doctor before getting a shot. These conditions include:
- Allergy to cobalt or cyanocobalamin
- Kidney problems
- Low potassium levels
- Iron and folic acid deficiency
Note: Intramuscular injections should only be administered by a medical professional. This reduces the chance of infection and significant side effects.
Should I Try a Vitamin B12 Shot?
Vitamin B12 shots are generally safe and have minimal side effects. They’re effective if your diet, or oral vitamin B12 supplementation, isn’t enough.
What if you don’t have a vitamin B12 deficiency? Could a B12 shot be beneficial? Evidence shows vitamin B12 shots have no real effect on health in people who aren’t deficient. There is no risk for these individuals to get a vitamin B12 shot, but there is no benefit either.
Your doctor may test your B12 levels before administering the injection.
Vitamin B12 Shots: Yea or Nay?
B12 shots are good for people who need them. If you want to get a B12 shot, talk to your doctor before getting one. After getting a dosage of this vitamin, you can decide if it affects your energy levels and how you feel.
Learn More:
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Sources
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