Vitamin B12 Injections For Weight Loss: Do They Work?

Weight loss is a long journey that requires lots of determination and patience. As for humans, it is quite common that we lose patience as days pass by. That is when we look for quick solutions that can be easily administered. When it comes to weight loss, many things have conquered the market but only some things seem to be as effective as the others.

In this article, we will be discussing B12 injections and their effect on your weight loss regimen. Is it healthy or does it come with its own set of side effects? Read on to uncover what we find.

What are Vitamin B12 injections? How are they made? 

Vitamin B12 Injections

Vitamin B12 is an essential component required by the body to conduct some of its important physiological functions like nutrient absorption and digestion. However, in many cases, the food we eat will not be able to provide it. Since it doesn’t occur naturally in our body like some other essentials, it becomes crucial to consume some to continue with smooth functioning.

This is when Vitamin B12 shots come into play. Individuals with deficiencies are prescribed b12 shots as a means to overcome the decrease of the said nutrient in their bodies. Vitamin B12 injections are made through a complex process that primarily involves its collection. Sources are either animals or via bacterial fermentation which then is purified to become medical grade.

Once its initial cleaning process ends, saline is added to the element to make it into an injectable form and then again sterilized to avoid any contamination during the process. The injection is then bottled and packaged safely to be delivered to drug marts to be dispensed by health workers. Usually, it is only given out with proper prescription and cannot be sold over-the-counter.

How Do B12 Shots Help You Lose Weight?

Though there is not much scientific evidence to support the claim, the abundance of anecdotal claims speaks for its reliability when it comes to losing weight. So how does it do that? Some people are of the notion that Vitamin B12 can be an ally when it comes to metabolic rate.

For the unversed, metabolic rate determines the rate at which our body uses fat for a particular chore. In obese individuals, the rate is usually slow and therefore they could increase weight faster than the others.  Taking B12 shots can indeed increase the rate of energy production in the body. However, its supporters believe that it can also alter the way the body breaks down carbs and fats. That is where the key lies to increasing one’s metabolic rate and thus achieving the given strategies for weight loss.

Moreover, they also nod to the claim that B12 shots help the body transport oxygen to the Red Blood Cells in an effective manner which otherwise is hindered in obese people. This means the body starts breaking fats properly and stops them from accumulating any leading again to the ultimate weight loss.

Lastly, a few supporters of taking Vitamin B12 injections are also known to have gained extra energy that could help them do the workouts faster and in a better manner. Doing workouts with full vitality could be crucial in dropping the kilos day by day. 

How to Take Vitamin B12 Injections for Results?

1. Opt for Cyanobalamin– Not only is it defined to be stable but also more affordable than its other forms.

2. Methylcobalamin– Its specialty in its ability to be easily absorbed by the body and therefore becomes more effective than its counterparts.

3. Hydroxocobalamin– Though available in injectable forms, its usage is quite limited except in a traditional hospital setting that requires specific doses of B12.

Dosing is the medicine’s right key to getting optimum results. For individuals suffering from the deficiency, the dosage would be between 1000 -2000 mcg daily or once a week.  However, when it comes to weight loss the dosage could be kept between 500-1000 and then maybe increased if the body doesn’t react. The dosage is to be based on a lot of factors including their type of nutrition and age.

Side effects of using Vitamin B12 injections for weight loss

There are obvious side effects of taking Vitamin B12 shots in cases when you are not in deficiency of the same. This may include-

  1. Allergic reactions – Its safety has never been questioned but in some rare cases, the possibility of an allergy cannot be overlooked. This could be a continuous itching, and red rashes and could even lead to swelling.
  2. Injection site reactions – Many times the site where the injection is administered could be affected adversely and can even lead to reddening. People also complain of their throats closing up.
  3. Interactions with medications – This can be avoided when compared to the other two. If you are taking specific medications for pre-existing conditions, you might want to watch out for any potential mix-up resulting in adverse reactions. The damage could be nothing or everything in both cases.
  4. Interaction with underlying conditions – Vitamin B12 is organic and cannot be deemed as a foreign substance. However, its reactions to conditions like diabetes or heart attacks are still to be studied in detail. While doctors generally believe it to be safe, there could be times when its safety cannot be guaranteed.


Vitamin B12 shots are quite popular for weight loss. It is useful for the body to perform some crucial functions and therefore can be present in the body. Nevertheless, it shouldn’t be regarded to be the ultimate medicine for weight loss. Even if you are taking it to lose weight diet control, exercise, hydration, and sleep should be a part of your schedule. No medicine can magically aid in weight loss and that should be kept in mind at all times.

Additionally, you should never hide an alternate reaction from the medicine to let the weight loss journey continue. Chances are the journey will make you sicker and you might even end up in a hospital bed.


  • Kuzminski AM, Giacco EJ, Allen RH, Stabler SP, Lindenbaum J. Effective treatment of cobalamin deficiency with oral cobalamin. Blood 1998;92(4):1191‐8. [PubMed
  • Scott JMFolate and vitamin B12Proc Nutr Soc, 58 (1999), pp. 441-448

Dr. Vanessa Rodriguez is a board-certified general practitioner with more than 15 years of patient care experience. She takes an integrative approach to patient care that considers the whole person – mind, body, and spirit – and is deeply committed to assisting her patients in achieving and sustaining optimal health. Dr. Vanessa is also a skilled writer and medical reviewer, specializing in preventive care and health promotion. Her articles are written in an approachable manner that is simple to comprehend and implement in one’s own life. Dr. Vanessa’s mission is to equip her patients and readers with the knowledge and resources necessary to live their greatest lives.

Leave a Comment