5 supplements for weight loss backed by science

Experts agree that eating wholesome, healthy meals, reducing calories, and increasing physical activity are the best ways to lose weight and keep it off long-term. Still, many people turn to vitamins and supplements for weight loss. In fact, around 15% of people have tried weight loss pills and weight loss supplements at some point in their lives (NIH-a, 2022).

The question is: Do vitamins help with weight loss? And if so, what are the best vitamins for weight loss?

Here’s what to know about losing weight with supplements and the best research-backed vitamins to boost metabolism.

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The multi-billion dollar weight loss industry offers products ranging from diet pills and supplements to weight loss shakes and protein bars, all promising weight loss. However, these weight loss pills and products may not be as effective as advertised (NIH-a, 2022).

This is partly because supplements and vitamins for weight loss aren’t as heavily regulated as you might imagine. The US Food and Drug Administration (FDA) oversees dietary supplements for weight loss and sometimes takes harmful weight loss products off the market. But they don’t formally approve vitamins and supplements for specific uses, including weight loss (FDA, 2022). So if you see a vitamin or supplement advertised as being able to help you burn fat or reduce body weight, you should take these claims with a grain of salt.

All that said, certain vitamins may act as metabolism boosters, help reduce body fat, improve your overall health, and potentially help you decrease your body weight. These vitamins work best when combined with other healthy lifestyle choices, like eating a healthy diet and engaging in physical activity.

Most of the vitamins that can be used as part of an effective weight loss routine are naturally occurring, meaning you can get them from natural foods. If you eat a balanced diet, you may already get enough of these vitamins. Still, some people may be deficient in these vitamins, and supplementing with them in pill form may help boost metabolism and burn calories more efficiently.

The best vitamins for weight loss and metabolism also usually have favorable safety profiles and minimal side effects because they have been studied extensively.

1. Vitamin B12

Vitamin B12 helps with many essential processes in the body, including the functioning of the central nervous system and the production of red blood cells. It also plays an important part in energy metabolism, and is sometimes used by athletes to increase their endurance (NIH-c, 2022).

Low levels of vitamin B12 are common, especially in people who don’t consume animal products, because animal products are the primary food source for vitamin B12. Others at risk of vitamin B12 deficiencies include older people, those with anemia or digestive disorders, and people who’ve had gastrointestinal surgery (NIH-c, 2022).

At this time, there is no proof that supplementing with B12 will boost your metabolism if you are not deficient. But people with a vitamin B12 deficiency may see a metabolism boost (NIH-c, 2022).

2. Vitamin D

Vitamin D is present in a limited number of foods—fatty fish and cod liver oil are the best food sources. You can also get it through sun exposure. Vitamin D helps with many processes in the body, like building bones and reducing inflammation. It also plays a vital role in processing sugar (NIH-d, 2022).

If you are wondering which vitamins are good for losing belly fat, you might want to add this supplement to your arsenal—some think of vitamin D as a fat burner. For example, a study published in The American Journal of Clinical Nutrition suggests that supplementing with vitamin D and calcium may reduce belly fat in people with overweight and obesity (Rosenblum, 2012). 

Because vitamin D is hard to obtain from foods and many of us don’t get adequate sun exposure, vitamin D deficiency is common, affecting almost 40% of Americans (Rubin, 2021). Contact your healthcare provider to find out if you may be deficient in vitamin D and whether supplementing could help you achieve modest weight loss.

3. Calcium

Calcium is a mineral found in abundance in the body. It’s rare for someone to be calcium deficient, but some groups are at risk, including postmenopausal women, older adults, people who don’t consume dairy products because of allergies or dietary preferences, people with a history of eating disorders, and adolescents (Beto, 2015).

Calcium helps build strong bones and teeth, and plays important roles in the circulatory system and neurological systems, and in hormone regulation. It also helps regulate metabolism and plays a part in weight management (NIH-b, 2022).

One study suggests that adding calcium and vitamin D supplementation to a lower-calorie diet may increase fat loss in people who typically consume low levels of calcium, compared to people who only lower their calorie intake (Zhu, 2013). Another study showed similar results, suggesting an association between calcium and vitamin D supplements and weight loss (Shahar, 2010).

4. Magnesium

Magnesium is a nutrient found in nuts, whole grains, and leafy greens. It helps regulate your nervous system, muscles, blood pressure, and blood sugar (NIH, 2021). There are indications that magnesium supplements may help people lose weight, especially if they have certain underlying conditions.

Studies suggest that supplementing with magnesium may help people lower their BMI and decrease their waist circumference, especially those with hypertension, obesity, magnesium deficiency, and insulin resistance (Castellanos-Gutiérrez, 2018; Askari, 2021).

5. Green tea extract

While green tea isn’t a vitamin, it’s one of the few weight loss supplements with some research behind it. You can consume green tea as a beverage, but you can also consume it in pill form.

Green tea is thought to potentially help with weight management because of its main ingredients: catechins and caffeine, which may help increase metabolism and act as appetite suppressants. Green tea supplementation may contribute to a small amount of weight loss in people with overweight or obesity (Jurgens, 2012).Green tea may also play a role in fat oxidation and glucose tolerance (Venables, 2008). It may also help regulate metabolism and improve appetite control (Rudelle, 2007; Rainsa, 2011).

Most over-the-counter vitamins and supplements marketed for weight loss are of little use and may be no better than a placebo. A report from the US Government Accountability Office states, “Little is known about whether weight loss supplements are effective, but some supplements have been associated with the potential for physical harm” (NIH-a, 2022). 

This is why it’s best to review any weight loss vitamins you are considering taking with your healthcare provider. Most vitamins shouldn't be a problem, as long as you take them in appropriate dosages, but they may not offer the health benefits you’re looking for, especially if you’re not deficient in them.

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

August 04, 2022

Written by

Wendy Wisner

Fact checked by

Chimene Richa, MD

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About the medical reviewer

Chimene Richa, MD

Dr. Richa is a board-certified Ophthalmologist and medical writer for Ro.