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Vitamin B12: The Ultimate Guide (Benefits, Dosage & Drawbacks)

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Vitamin B12: The Ultimate Guide (Benefits, Dosage & Drawbacks)

What is Vitamin B12?

Vitamin B12 is an essential nutrient that's needed to maintain your health. It's found naturally in animal foods, it’s available as a dietary supplement, and it's even added to energy drinks and other fortified foods. Also known as cobalamin, B12 plays a hugely important role in your body for cell generation, DNA production, and nerve function.

On the rest of this page, we'll get into how it works, why you need it, and how you can incorporate it into your diet.

How does Vitamin B12 work?

After you take Vitamin B12, it binds to a glycoprotein in your stomach called intrinsic factor. After that, it's transported to your small intestines, where it can be absorbed into the bloodstream (1). From the bloodstream, the vitamin is then transported to your liver, where it's can be stored and released into your body’s cells and tissues when needed.

Why you need Vitamin B12

Vitamin B12 plays a crucial role in maintaining your overall health. For starters, it helps regulate your energy levels, metabolism, and also the production of red blood cells. The best Vitamin B12 supplement can help regulate your body's production of energy, and it protects against certain health conditions (2). It helps maintain healthy nerve cells and allows your body to metabolize carbohydrates, fats, and proteins.

Can your body produce Vitamin B12?

No, it can't produce Vitamin B12 on its own, so it has to be consumed through dietary sources (3). Thankfully, you do have the ability to store Vitamin B12, and you can also eat food sources that are rich in B vitamins over a long period of time to meet your body's needs. But the easiest and most convenient way to ensure you have enough B vitamins is to take a dietary supplement on a daily basis.

Make sure to check out VitaRx's Vitamin B12 to make sure you're getting enough B12 in your system. Our dietary supplements are expertly formulated with high-quality ingredients for the best results. Simply add B12 to your custom vitamin packs, and you're well on your way to improving your health and keeping your body functioning at its best!

What are some signs of a Vitamin B12 deficiency?

Vitamin B12 deficiency can have some serious consequences. A deficiency can cause anemia, nerve damage, and even cognitive decline. For this reason, it's important that you consume adequate amounts of B12 either through dietary sources or supplementation (4). Here are some of the symptoms of low B12 that you should watch out for:

  • Weakness or tiredness
  • Heart palpitations and shortness of breath
  • Smooth tongue
  • Reduced vision or vision loss
  • Pale skin
  • Constipation, diarrhea, gas, loss of appetite, and other digestion issues
  • Numbness, tingling, and muscle weakness
  • Mental health problems like depression, memory loss, or poor concentration

If you suspect that you're experiencing Vitamin B12 deficiency, then it's best that you speak to a healthcare professional as soon as possible. Keep in mind that we offer high-quality Vitamin B12 supplements that can deliver the daily dose of B12 that your body needs.

More importantly, our supplements are made with high-quality ingredients and manufactured according to the Food and Drug Administration's (FDA's) Good Manufacturing Practices (cGMPs). You can rest assured that you'll be incorporating the best supplements into your daily routine.

What causes Vitamin B12 deficiency?

A deficiency in Vitamin B12 is the result of not consuming enough B12 in your diet. But there are also some conditions that interfere with B12 absorption, such as Celiac and Crohn's disease (5).

  • Celiac disease: Celiac disease is an autoimmune condition that affects the digestive system. It's triggered by eating gluten. With untreated celiac disease, the upper part of the small intestine can get damaged and prevent you from absorbing nutrients like Vitamin B.
  • Crohn's disease: This disease is a chronic inflammatory bowel disease that affects the lining of the digestive tract. When the small intestine is heavily inflamed, it affects the absorption of B12.

What are the benefits of Vitamin B12?

Alt text: Person jogging full of energy from the best Vitamin B12 supplement

The Cleveland Clinic states that one of the main benefits of Vitamin B12 is that it helps reduce fatigue and improve energy levels. This is all thanks to its importance for your body's metabolism and, more specifically, the ability to convert carbohydrates into energy. It can also help reduce your risk of developing anemia, which is a condition that reduces the ability of your blood to transport oxygen.

Vitamin B12 can even improve the production of neurotransmitters for better focus and alertness (6). In addition to these benefits, Vitamin B12 positively affects your mental health (7). Here are some of the top benefits of Vitamin B12:

  • May reduce the symptoms of depression, anxiety, and fatigue
  • May improve cognitive function and memory
  • May slow down the progression of age-related macular degeneration
  • Supports serotonin production

VitaRx's Vitamin B12 supplements are a great way to support overall health and wellness. Our supplements are manufactured in the US and are tested by advanced private laboratories. This is to ensure that they're of high quality, meet the FDA's cGMPs, and are completely free of contaminants.

What's the recommended Vitamin B12 dosage?

When taking any supplement, it's crucial that you take the correct dose and understand any potential risks or interactions with other drugs. This is the best way to reap the full benefits of the best Vitamin B12 supplement.

Dosage per age group

Here, you'll find the recommended daily dose for Vitamin B12 (8).


Age Range

Male RDA (mcg)

Female RDA (mcg)

Pregnancy RDA (mcg)

Lactation RDA (mcg)

Birth-6 Months





7-12 Months





1-3 Years





4-8 Years





9-13 Years





14-18 Years





19+ Years





Table 1: Recommended Dietary Allowances (RDAs) for Vitamin B12


Who should take it?

People who don't consume enough B12 in their diet will need to take a supplement to make up for it. This includes vegetarians and vegans, who may not be getting enough B12 in their system due to the lack of animal products. There are only a few plant-based foods that contain B12. Elderly people may also not be getting enough B12 due to poor ability to absorb nutrients or an imbalanced diet.

Who should not take it?

There are a few types of conditions that can potentially interfere or negatively interact with Vitamin B12 tablets. This includes having a low amount of potassium, atrophic gastritis, or a past history of complete removal of stomach (9). Atrophic gastritis causes chronic inflammation in your stomach lining, which affects vitamin absorption.

How much is too much? (Vitamin B12 overdose)

Thankfully, you can't overdose on Vitamin B12. According to the Mayo Clinic, higher doses are safe because your body only absorbs as much as it needs. Any excess B vitamins simply pass through urination (10).

Source of Vitamin B12


Alt text: Sunny side up egg on a pan; a great B12 food source on top of taking the best Vitamin B12 supplement

Vitamin B12 can be found in many different foods. Here are eight of the most common food sources containing Vitamin B12:

  1. Fish and shellfish
  2. Red meat
  3. Dairy products such as milk and eggs
  4. Poultry
  5. Fortified non-dairy milks
  6. Fortified cereals
  7. Seaweed
  8. Nutritional yeast

Some fermented plant-based foods also contain B12, such as tempeh (11).


To avoid nutritional gaps, you may want to opt for the best Vitamin B12 supplement. Look for B12 supplements that contain the active form called methylcobalamin. This form of B12 is more easily absorbed by the body than other forms. You can also take a supplement that contains other B vitamins like folate, thiamine, riboflavin, and niacin. These vitamins work together to help your body work more effectively.

VitaRx has all the vitamins and supplements that can help you reach your health goals. Our daily vitamin packs are customized and personalized to meet your needs and make it easier for you to improve your overall health. You'll only find the highest-quality B vitamins and nutrients in capsule form, and it's all tested by advanced private laboratories. More importantly, we offer a high-quality B12 vitamin supplement so you can take advantage of its health benefits.

What to look for in nutrition supplements

When it comes to choosing the right dietary supplements for you, there are some things you should consider, like the supplement's dose, delivery method, quality, and more. Keep reading to learn all about those below.

Dosage and Potency

To maximize the health benefits of a B12 supplement, it's important that you take the correct dose. The optimal amount is based on individual characteristics like age, gender, weight, and overall health condition. While there are no side effects from taking too much B12, paying for the right dose per serving will yield better results and help you reach the recommended daily value.

Quantity and Delivery Method

Buying vitamins in bulk can be a waste if you don't use them all before the expiration date. So, it's essential that you purchase the right amount to fulfill your needs. That's what makes our 30-day supply of vitamin packs such a great option for most. The daily packs make supplementation easier and more convenient. You can also choose a delivery option that suits you best, like capsules that are easy to ingest and take every day.

Quality and Manufacturing

Not all supplements are made equally. Vitamin B12 dietary supplements should be made with high-quality methylcobalamin. With diluted potency, you may not see the full extent of its benefits. Make sure your chosen supplement is tested and is produced in a facility that meets the FDA's GMP requirements. Choose only the highest-quality products manufactured in GMP-certified facilities.

Why VitaRx

Reason 1 Dosage / Potency

VitaRx's supplements are specially formulated to provide the right dosage. We use high-quality ingredients and strict manufacturing standards to ensure that each dose contains the optimal active ingredients for maximum effectiveness.

Reason 2 Quantity / Delivery Method

VitaRx offers daily supplement packs, so you never have to worry about overspending on a large bottle of supplements,s or keeping track of the expiration dates again. And all our supplements are in tablets and soft gel form, which are more convenient for traveling, than powders or liquids, as they can fit easily in a purse or bag.

Reason 3 Quality/ Manufacturing

All VitaRx supplements are manufactured in the US and tested by third parties. All products are manufactured in facilities that comply with the FDA’s Good Manufacturing Practices (cGMPs); All our organic products are certified by Organic Assurance International (QAI). And all organic products comply with the National Organic Program (NOP).

Vitamin B12 FAQ

How to store Vitamin B12?

Your supply of Vitamin B12 should always be kept in a cool and dry environment, away from direct sunlight or excessive moisture. The best Vitamin B12 supplement storage options should include storing them at room temperature to ensure their effectiveness; this includes avoiding high temperatures and humidity as well as keeping them secured out of reach of children and animals for safety reasons.

What food is highest in Vitamin B12?

According to WebMD, high-B12 food sources include beef and shellfish. Clams have 84.1 mcg of B12, while beef liver has 70.7 mcg. For plant-based foods, one tablespoon of nutritional yeast will have 4.8 mcg which meets twice the recommended daily intake.

How can I raise my B12 levels fast?

One of the most effective ways you can increase your B12 levels is to take a dietary supplement. And luckily for you, we offer a B12 vitamin that can be taken orally. Taking a supplement allows you to quickly increase your B12 levels and help you feel better. You can also opt for a B12 shot. Either way, it's critical that you talk to your doctor before taking a supplement to make sure it's right for you.

Is Vitamin B12 worth taking?

Definitely! Vitamin B12 is an essential vitamin for so many of your bodily functions. It's necessary for the production of red blood cells, which carry oxygen throughout the body, as well as for the production of DNA and RNA, which are needed for cell growth and division. Vitamin B12 also helps maintain a healthy nervous system, supports your energy levels, and contributes to improved serotonin levels which help you feel happier and calmer.

What diseases can cause you to have low Vitamin B12 levels?

There are a few conditions that can cause you to have low Vitamin B12. This includes pernicious anemia, atrophic gastritis, celiac disease, Crohn's disease, and more. Taking certain medications—like proton pump inhibitors and H2 blockers—can also cause you to have low Vitamin B12 due to interference with absorption (4).

How long does it take to restore B12 levels?

According to Harvard Health Publishing, a response to Vitamin B12 treatment can be seen within as little as 48 to 72 hours. But if you're trying to fully recover from a deficiency, you can expect it to take several months depending on the severity.


Overall, Vitamin B12 is an essential nutrient for your body, and supplementation is an effective way to ensure that you have enough. Vitamin B12 dietary supplements are available in tablets, capsules, liquids, and injections, and they're generally safe and well-tolerated. It's important that you speak to a healthcare professional before beginning to supplement with Vitamin B12 to ensure the right dose for your age and health.

And, of course, don't forget that our convenient daily vitamin packs are a great option to make sure you get every single one of the nutrients necessary for your health. We offer the best Vitamin B12 supplement made with the best practices according to GMP guidelines. For maximum effectiveness, our B12 supplement comes in a 5 mg vegetarian capsule. And you can easily add it to your personalized daily vitamin packs for a month-long supply.

Key takeaways

  • Vitamin B-12 is a water-soluble vitamin that plays a role in the formation of cells and the maintenance of the nervous system.
  • It's not a vitamin your body can produce on its own, so it has to be consumed.
  • Without sufficient Vitamin B12, the body may experience tingling, fatigue, muscle weakness, heart palpitations, and pale skin.
  • Vitamin B12 plays an important role in the body's metabolism, and it can have a positive effect on energy levels, mental clarity, and overall well-being.
  • Those who don't get enough B12 from food should consider taking Vitamin B12 tablets to fill nutritional gaps, including pregnant women and the elderly.
  • People who have atrophic gastritis, low potassium, or other predisposing factors should avoid taking a B vitamin supplement.
  • B12 can be found in a variety of foods, but the best option is to take daily doses in a supplement form to meet your recommended daily intake.


  1. https://www.nhlbi.nih.gov/health/anemia/vitamin-b12-deficiency-anemia
  2. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/ 
  3. https://my.clevelandclinic.org/health/diseases/22831-vitamin-b12-deficiency  
  4. https://www.webmd.com/diet/vitamin-b12-deficiency-symptoms-causes 
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3271502/ 
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7688056/ 
  7. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/ 
  8. https://www.webmd.com/drugs/2/drug-1010/cyanocobalamin-vitamin-b-12-oral/details/list-contraindications 
  9. https://www.mayoclinic.org/drugs-supplements-vitamin-b12/art-20363663 
  10. https://pubmed.ncbi.nlm.nih.gov/2380647/ 

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