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Home arrow Nutrition arrow Weight Management arrow Are B12 Shots Effective for Weight Loss?

Are B12 Shots Effective for Weight Loss?

Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: April 7, 2023
7 min read 1359 Views 0 Comments
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Trying different products for weight loss can be frustrating, especially when you can’t find anything that works. B12 shots are said to boost your metabolism, but is this true? How do they target stubborn fat? We explain what B12 shots are and if they help you lose weight.

B12 shots for weight loss

B12 shots aren’t the most common way to drop a few pounds. These injections are usually the last resort when it comes to your weight loss journey. 

People usually follow high-intensity exercise or low-calorie diet plans to lose weight, but this might not work for everyone. Those with a vitamin B12 deficiency may struggle to exercise regularly due to a lack of energy. So why not take a vitamin shot to change that?

Shots might seem like a strange option for your weight loss journey since injections relate to treating medical conditions. However, can B12 shots give you enough energy to work out? Will they strengthen your metabolism, leading to a better fat-burning state?

In this article, you’ll learn about vitamin B12 shots and whether they’re good for weight loss. 

B12 Shots for Weight Loss – Are They Helpful?

Vitamin B12 shots can help you lose weight if you pair them with a weight loss plan. The B12 itself won’t directly burn body fat, but it can prevent you from feeling lethargic. If you have more energy, you’ll feel motivated to exercise and reduce your body fat. 

B12 shots indirectly boost the metabolism when you’re losing weight. Having a strong metabolism is also great for keeping weight off, especially once completing your fat loss program. Vitamin B12 may encourage your body to burn more calories during sleep too.

Taking B12 shots shouldn’t be your primary focus for weight loss, though. High-intensity interval training (HIIT) and eating low-calorie foods will reduce your body weight in no time. B12 shots are only there to give you a lasting energy boost, so only take them after seeking medical advice.

Just remember that B12 is naturally present in animal-based foods, like eggs and meat. If you’re vegan or vegetarian, you might suffer from B12 deficiency. You can take these B12 shots to balance your energy levels and have the motivation to achieve a healthy weight. 

What Are B12 Shots?

A B12 shot is a form of injection that contains vitamin B12. This important vitamin helps keep your nerves and blood cells healthy by assisting in red blood cell formation. Without vitamin B12, you might experience tiredness, numbness, and poor balance. 

Vitamin B12 shots are injected into muscle tissue every 1–3 months until the person feels physical improvements. You can get these shots in a local pharmacy or weight loss clinic. Anyone can ask for B12 shots if they wish to get more vitamin absorption in their body. 

Most B12 shots contain a synthetic version of vitamin B12 and certain types of amino acids. These ingredients may give you more energy to function properly.

One reason people might get a B12 shot is to strengthen their metabolism. B12 is known for fighting fatigue, leading to a better performance at the gym. You can also find vitamins in B12 supplements, animal products, fish, meat, eggs, fortified breakfast cereals, and dairy products.

What are B12 shots good for?

B12 shots are great for preventing and treating anemia – a condition in which your body doesn’t have enough red blood cells. People with a vitamin B12 deficiency also take this regular injection, as it fuels them with enough energy to function properly.

Vitamin B12 is one of the 8 B vitamins that help your body metabolize food into fuel. B12 is a water-soluble vitamin that needs to be consumed through healthy food and supplementation. People who don’t have enough of this vitamin may develop anemia. 

Red blood cells may not adequately migrate from the bone marrow into the circulation with vitamin B12 deficiency. This might cause cell distortion, making anemic people feel extremely weak. Vitamin injections are excellent for alleviating symptoms and regenerating cells to combat anemia.

B12 shots also benefit your metabolism, brain health, skin, hair, bones, and nails. This is due to the vitamin strengthening your brain neurons. Consider taking these injections now and then to build a healthier lifestyle, but always seek medical advice before doing so.

You can talk to a doctor about taking shots or supplements. A medical professional can see how B12 might improve physical and internal components. 

Do B12 injections boost metabolism? 

Yes, B12 shots can strengthen your metabolism by providing energy boosts. Vitamin B12 works to support a healthy nervous system and keep your body running efficiently. Those with anemia or deficiencies usually take B12 shots to gain lasting energy levels.

Vitamin B12 is great for enhancing your physical performance throughout the day. It converts the food you eat into sugar and other fuel that maintains a healthy metabolism. People believe that B12 shots can enhance weight loss efforts when trying to exercise and diet. 

A stronger metabolism may encourage you to lose weight. B12 shots can help you attain your dream body just by fueling your system with energy. More physical energy leads to a better cardio-based workout. If your heart is pumping, you’re burning more calories and fat cells.

How Quickly Does the B12 Shot Work?

Your first B12 shot may work within 48–72 hours, depending on how fast your body absorbs the vitamin. During this time, the body produces new blood cells to circulate in your blood. People with anemia or deficiencies may need several shots to feel the impact.

Since this injection goes into muscle, your body can quickly absorb the nutrients. The stomach doesn’t always process vitamins properly due to high levels of acid or age-related causes. Shots are usually the best way to feel physical and mental differences in a short time span. 

If you have a vitamin B12 deficiency, the pharmacist might recommend getting 2–3 injections over several weeks. This ensures your body can fully absorb the vitamin and produce enough red blood cells. Once the shot has kicked in, you won’t need to take them regularly

How Often Should You Get a B12 Shot for Weight Loss?

Some practitioners may recommend people to get B12 shots up to 2 times a week for energy. More energy leads to increased motivation to work out. This “weight loss” injection won’t directly make you lose weight, but it can build a stronger metabolism. 

People wanting to lose weight and prevent future weight gain usually have one shot per week, depending on their energy levels. The daily intake can also depend on your age, diet, and medical factors. Speak to a medical professional beforehand to get their advice. 

Those with anemia or deficiencies need two or more B12 shots over the course of 3 weeks to allow their body to absorb and produce blood cells.

However, it’s important to talk to your doctor about B12 injections. Too much could trigger side effects in your body. A medical professional can advise you on how many shots to take and if you should consume dietary supplements for weight loss purposes. 

Should You Take B12 Shots?

You can take vitamin B12 shots, but there are better ways to lose weight. Shots are generally considered to be safe for anemic conditions. To achieve positive weight loss results, exercise regularly and gain B12 nutrients from a healthy diet. 

There are certain people who should take B12 shots if they’re not getting enough vitamins from their diet. Being over the age of 50 could mean you aren’t producing healthy cells. The same goes for vegans and vegetarians who don’t get B12 from food consumption. 

Surgery can also increase your vitamin B12 deficiency risk if your stomach can’t absorb nutrients. This includes weight loss surgery and alterations to the digestive tract. If you’re in these categories, speak to your doctor about taking B12 shots.


What are the side effects of B12 injections?

It’s possible for people to get allergic reactions. If you’re sensitive to needles, consult with your doctor before taking any vitamin injections. They can tell you the ingredients of a B12 shot to make sure it’s right for you.

Does vitamin B12 cause weight gain?

No, vitamin B12 can’t cause weight gain. This only happens if you consume too many calories. B12 only works to improve cells in your body and give you plenty of energy to work out. Weight gain is usually a sign that you’re eating too much or have an underlying health condition. 

How long does a B12 shot last?

The effect of vitamin B12 injections can last around one week after the first injection. However, this depends on your body and how fast it absorbs the vitamin. You’ll have options to take more shots over a few weeks if you want to continue experiencing the lasting energy boosts.

A Word From Our Dietitian

Vitamin B12 shots are helpful for those who have anemia or vitamin deficiencies. It won’t directly progress your weight loss results or help your body drop a few pounds. Therefore, you need a sustainable workout plan that involves cardio-based exercise and healthy, low-calorie meals.

B12 shots still offer plenty of health benefits for the human body. It can improve brain function, leading to better mental health. The same goes for improved skin, bones, hair, and nails. You can take this B12 injection to notice more physical and internal differences.

Speak to a doctor if you’re unsure about getting injections. They may give you vitamin supplements or prescribed medication to treat B12 deficiency. It’s always better to consult with a health professional who understands your medical background and needs.


Weight loss requires plenty of time and effort.

No injections can directly burn fat on your body and shed unwanted pounds – that only happens through intense exercise and dieting. If you want more B12 consumption, eat nutritious foods or request weekly vitamin B12 injections from a pharmacist. 

Written by Edibel Quintero, RD
Edibel Quintero is a medical doctor who graduated in 2013 from the University of Zulia and has been working in her profession since then. She specializes in obesity and nutrition, physical rehabilitation, sports massage and post-operative rehabilitation. Edibel’s goal is to help people live healthier lives by educating them about food, exercise, mental wellness and other lifestyle choices that can improve their quality of life.
The article was fact checked by Rosmy Barrios, MD
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Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: April 7, 2023
7 min read 1359 Views 0 Comments

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