Does B12 help with weight loss?

Vitamin B12 (including vitamin B12 shots) is not proven to help with weight loss. Research on the connection between B12 and weight is mixed; B12 shots are generally safe when prescribed, and there are research-backed alternatives (like diet, exercise, and weight loss medications) for people looking to manage their weight.

The short answer is that vitamin B12 shots probably won’t help you lose weight. B12 shots are not a scientifically proven tool for weight loss, especially for those who follow a balanced diet and get enough B12.

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Where does the link between B12 and weight come from? 

Several studies have documented a link between low levels of B12 and weight gain and obesity in both children and adults. The question is: do low B12 levels actually cause weight gain, or is the link just an association, with something else driving both low B12 and obesity? Another question in this context is, can B12 supplements help you lose weight?

According to a large sample of over 9,000 American adults, low B12 levels are associated with obesity, independent of race or ethnicity, gender, and socioeconomic and lifestyle factors. The same study also found that people with higher B12 levels are less likely to have obesity.

But, more research is needed to determine whether low B12 levels actually cause obesity, or if there are other contributing factors. The study also didn’t show that the vitamin can help lose weight.

In studies of mice, severely reducing their vitamin B12 levels significantly increased their body fat percentage and led to the development of fat tissue. Studies of rats have found that supplementing with B vitamins helped reduce their weight gain by improving their metabolism. 

However, what works for animals may not work for us, and more research regarding the effect of vitamin B12 on human body fat and metabolism is still needed.

Yes, vitamin B12 shots are safe, as long as they’re prescribed to you by your healthcare provider who has deemed them safe and appropriate for you. Your provider might prescribe vitamin B12 injections if you have a severe vitamin B12 deficiency and/or conditions that make it hard for your body to absorb vitamin B12. Through injections, B12 is much more easily absorbed by the body. 

If you are not deficient in B12, it's unlikely that B12 shots would benefit you.

Adults need 2.4 micrograms (mcg) of vitamin B12 daily, and more if pregnant or breastfeeding. If you’re looking to boost your B12 levels naturally, you’ll be happy to find that there are several foods that are high in vitamin B12. These include:

• Beef, especially beef liver

• Turkey

• Poultry

• Clams

• Tuna

• Salmon 

• Eggs

• Milk

• Yogurt 

• Cheese

• Fortified nutritional yeast

• Fortified breakfast cereal

If you ever wonder if a food contains vitamin B12, just check the nutrition label. 

You can also supplement dietary sources with over-the-counter B12. Vitamin B12 shows up in most multivitamins, and vitamin B12 supplements are available in tablet, liquid, capsule, lozenge, and even sublingual form (under the tongue). For vitamin B12 injections or nasal gels, you'll need a prescription from your healthcare provider.

There are various other legitimate ways to manage your weight or lose weight, including the following.

Eat a healthy diet

First things first, take a look at what you’re eating. Cut out processed foods and added sugars, and fill up your plate with minimally processed whole foods. Eating foods high in protein and fiber can promote satiety, aka helping you feel fuller for longer. 

You may also consider tracking your calorie intake so you can aim for a calorie deficit — which means consuming fewer calories than you burn daily. 

Exercise regularly

Alongside a healthy diet, regular exercise is key for weight loss. Aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous aerobic activity per week. Plus, aim to incorporate resistance training/strength training twice a week. This will help preserve your muscle mass as you lose fat.

Stay hydrated

Staying hydrated is important for your overall health — plus, sometimes feelings of thirst can mimic feelings of hunger. 

Research suggests that drinking water can increase your metabolism if you’re dehydrated, helping you burn calories. Additionally, studies show that drinking water before you eat a meal can help you feel fuller and decrease appetite.

Consider weight loss medications

If you’re struggling to lose weight, speak to a healthcare provider. They can discuss your history and determine if weight loss medications like prescription glucagon-like peptide 1 receptor agonist (GLP-1) medications would be a good fit for you.

GLP-1 medications, such as Wegovy (semaglutide) and Zepbound (tirzepatide), target hunger hormones in your brain, helping you to feel less hungry. They also slow gastric emptying (slowing down how food moves through your gut), which helps you feel fuller for longer.

See if you qualify

Vitamin B12 supplementation is not a proven weight loss strategy, especially in and of itself. Here are a few other considerations.

• Although research suggests that B12 levels are lower in people with obesity, it doesn’t prove that this B vitamin can help with weight loss.

• There isn’t evidence that B12 directly burns fat or leads to weight loss.

• B12 shots are only necessary if you’re severely deficient in B12 and/or have a condition that makes it hard for your body to absorb B12.

• If you want to lose weight, consider proven strategies like eating a healthy diet, exercising regularly, maintaining a calorie deficit, and potentially weight loss medications.