Medically Reviewed

Can Vitamin B12 Really Help You With Weight Loss and Management?

Vitamin B12 is an important vitamin for many aspects of your overall health. Researchers are looking into its effects on weight management.

So, what can Vitamin B12 do for weight management?

Vitamin B12 is a water-soluble vitamin that’s necessary for many areas of your health, including in the formation of DNA and red blood cells, and the promotion of heart health, brain health, energy production, and more. You’ll find it naturally present in some foods – mostly from animal sources – and added to others. It’s also available in supplement form. Those on a vegetarian or vegan diet are especially prone to B12 deficiency.

In recent years, vitamin B12 shots and supplements have gained popularity among people looking to lose weight. While there’s a lot of research to back up claims about vitamin B12’s benefits for overall health, research has yielded mixed results when it comes to weight management. Proponents of B12 as a weight management supplement point to its potentially positive effects on energy levels and metabolism. Experimental data has shown that those taking B12, along with vitamin B6 and chromium, experienced reductions in weight gain compared to other groups.

Can B12 boost fat burning in the body?

It is true that vitamin B12 is involved in the metabolism of macronutrients like fats, carbohydrates, and proteins. However, the body's ability to metabolize and burn fat is a complex process influenced by numerous factors, including overall caloric intake, physical activity levels, hormonal balance, and genetic predispositions. Simply increasing your vitamin B12 intake may not significantly impact fat burning or weight loss without addressing these other factors.

The potential of B12 to support muscle growth

Vitamin B12 is important for various aspects of muscle growth and maintenance. Vitamin B12 takes part in protein metabolism, including the synthesis of new proteins. Adequate protein synthesis is essential for muscle growth and repair. The vitamin’s role in the production of red blood cells, which are responsible for delivering oxygen to the muscles, can also support optimal muscle function and growth. Vitamin B12’s roles in energy production and nerve impulses conduction during exercise support the muscle contraction needed to stimulate muscle growth. Of course, many other factors play a role in building muscle, such as resistance training, adequate protein intake, and sleep and recovery.

What impact does B12 have on metabolism & energy levels?

The relationship of vitamin B12 with energy occurs at a cellular level. B12 does not lead to a burst of energy like consuming caffeine; however, adequate B12 is necessary for healthy and balanced energy potential in the body.

How vitamin B12 helps convert food into energy

Vitamin B12 is essential in the metabolic pathway called the citric acid cycle. In this process, vitamin B12 aids in one of the steps in the metabolism of macronutrients carbohydrates, fats, and proteins into energy. Through a series of enzymatic reactions, vitamin B12 helps break down the macronutrients into smaller units able to be used by the body for producing biological energy called adenosine triphosphate (ATP).

A review of vitamin B12 studies in humans concluded that B12 does indeed play an important role in fat metabolism, observing that B12 deficiencies can be linked to difficulties with weight management. By supporting proper metabolism, vitamin B12 helps the body efficiently extract energy from food and maintain optimal energy levels.

How B12 encourages a healthy weight by supporting overall health

Weight management involves numerous processes in the body working well and in concert together, as well as social and lifestyle factors. Vitamin B12’s role in supporting overall health can support those bodily processes needed for weight management.

Vitamin B12 in DNA synthesis and red blood cell formation

B12 is an essential nutrient for DNA synthesis, the literal building block and structural foundation of the human body. Vitamin B12 in the form of methylcobalamin is able to transfer a methyl group in a process called methylation, which involves enzymatic reactions needed for DNA and protein synthesis and gene expression. Methylation is a crucial process involved in a multitude of functions in the body involved in metabolism.

Vitamin B12 on brain function and heart health

The brain and heart use enormous amounts of cellular energy. As such, the body requires vitamin B12 for many cellular functions including brain and heart health.

Part of the methylation cycle leads to the formation of homocysteine. Keeping homocysteine levels in check is important for maintaining cardiovascular wellness. Research has shown that adequate B12 can support proper homocysteine levels and helps the body with energy metabolism.

Healthy B12 intake and absorption support brain function and central and peripheral nervous system wellness. Even levels that do not reach true deficiency have the potential for long-term effects on cognitive function. However, B12 supplementation alone might not produce the full effect of supporting cognitive function. Certain educational games can also support brain health and cognitive function.

Other dietary and lifestyle steps can support brain and heart health. Include at least 2 servings of fatty fish per week to get adequate intake of EPA and DHA (types of omega-3 fat), or choose a vegetarian source like the Veggie Omega supplement. Aim for regular physical activity of at least 150 minutes per week.

Vitamin B12 on the respiratory and circulatory systems during exercise

While it supports many aspects of cellular energy, vitamin B12 has not been shown to improve athletic performance or exercise outside of situations where there is a nutritional deficit present.

Vitamin B12 and its role in nutrient absorption

Adequate stomach acid and a compound called intrinsic factor, produced along with stomach acid, are needed for vitamin B12 absorption. Many factors impact the body’s ability to absorb and use vitamin B12 from the diet, including aging, genetics, dietary intake, absorption issues, and depletion with certain medications. In our B12 supplement, we include 3 types of active B12: methylcobalamin, adenosylcobalamin, and hydroxocobalamin along with acacia, a prebiotic and fiber to boost absorption. The active forms of B12 (methyl and adenosylcobalamin), are known as “coenzyme” forms of B12 which means that they are better utilized by B12-dependent enzymes and reactions within the body.While the recommended daily amount of vitamin B12 for adults is 2.4mcg, higher doses have been found to be safe. Your body absorbs only as much as it needs, and any excess passes through your urine.

Regarding B12 and its role in nutrient absorption, this study shows that B12 along with other B vitamins play an important role in maintaining a healthy gut. Vitamin B12 levels specifically support maintenance of the mucosa and villi. The lining of the intestines is also referred to as the mucosa and it plays a critical role in optimizing nutrient absorption and digestion. Villi are finger-like projections in the small intestine that also help with nutrient absorption. Maintaining optimal levels of B12 and other B vitamins contribute to nutrient absorption.

What are the signs of vitamin B12 deficiency?

A serum blood level of 200 pg/mL or lower is considered a vitamin B12 deficiency. If a deficiency is established, the cause of vitamin B12 deficiency should always be further investigated. Some symptoms of B12 deficiency can include:

  • Shortness of breath
  • Fatigue
  • Weakness
  • Poor balance
  • Skin pallor
  • Brain fog
  • Day to day irritability
  • Changes in mood
  • Soreness of mouth/tongue

These symptoms are not exclusive to B12 deficiency so if you notice any of these symptoms be sure to talk to your doctor.

Can B12 deficiency contribute to weight gain?

Many factors affect a person’s body weight, but there does seem to be a connection between B12 and weight management. A 2019 retrospective analysis study did show that blood levels of vitamin B12 inversely correlated with weight challenges even after adjusting for notable variables. However, direct conclusions cannot be drawn from B12 levels alone. More research is needed to understand the mechanism for this correlation. Nevertheless, knowing your vitamin B12 levels and how to optimize them may be a helpful step towards weight management along with a healthy lifestyle and plan.

B12 injections and weight management

One of the most common and effective ways to increase B12 levels and treat B12 deficiency is through B12 injections. Injections typically are in the form of hydroxocobalamin, methylcobalamin, or cyanocobalamin, which can all be effective at raising B12 blood levels and treating or preventing a B12 deficiency. Injections can be especially beneficial in situations where digestion is compromised, since injections bypass the digestive system and go straight into the bloodstream. Injections are prescribed by a doctor and given into a muscle or underneath the skin in the subcutaneous layer.

Because of the effectiveness of injections at raising B12 blood levels, injections can be particularly useful for boosting energy and enhancing metabolism in those with low vitamin B12. Taken together, these benefits may support weight management goals if low vitamin B12 levels are present.

Results from this study shows that oral supplementation can be more cost effective than injections. So the method you choose to use for supporting your B12 levels should be what you and your medical team decide fits your body, budget, schedule, and lifestyle. Talk to a doctor to get a sense of your body’s B12 levels and see what is the right course for you.

Does vitamin B12 increase appetite or hinder weight loss efforts?

Studies show that a B12 deficiency can sometimes result in a loss of appetite. If you take a B12 supplement to treat this deficiency, you may experience an increase in appetite, but that’s really a restoration of a normal level. In general, taking B12 should neither increase nor decrease appetite.

What is the best form of B12 to take?

B12 supplements are available in a variety of active forms. Care/of’s Vitamin B12 supplement is formulated with three active forms of B12: methylcobalamin, adenosylcobalamin, and hydroxocobalamin, which the latest research has shown are the most bioavailable and easily used by the body. Dubbed “The Energizer'' and available in a 30-day supply, our B12 supplement is also suitable for vegans and vegetarians and supports energy metabolism. All of our supplements are made with maximum absorption in mind.

What foods are naturally rich in vitamin B12?

Vitamin B12 is naturally found in foods of animal origin; other foods are fortified with it. Some foods that include B12 are:

  • Red meat, chicken, and turkey
  • Fish, such as salmon and tuna
  • Shellfish, such as shrimp and oysters
  • Dairy products, such as milk, yogurt, and cheese
  • Eggs
  • Fortified plant-based milks
  • Fortified cereals

Including foods that contain B12 regularly in your meals is an excellent way to meet the established Recommended Dietary Allowance (RDA) of 2.4-2.8 mcg for most adults.

How long does it take to see weight loss results are increasing B12 intake?

Blood levels of vitamin B12 can start to increase within a relatively short period of time after beginning supplementation. New red blood cells can start to be produced within just a few days. A study on intramuscular B12 injections in athletes showed a significant increase in B12 levels in the blood within just 1 week to over 1000 pg/mL.

However, the exact timeframe for noticeable changes in blood levels can vary depending on factors such as the dosage, frequency of supplementation, individual metabolism, and initial B12 status.

The Bottom Line

Vitamin B12 is a very important water-soluble vitamin, playing an essential role in many areas of your health. Its positive impact on energy and metabolism has led to greater interest in B12 as a support for weight management. While there’s some evidence to support the claim that B12 can help with weight management, more research – particularly of human subjects – is needed. Boosting your intake of vitamin B12 through foods and supplements can maintain healthy levels, while improving your energy levels and fighting fatigue. If your doctor has determined that you are B12 deficient, you may be prescribed B12 supplementation or injections.

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