8 vitamins and 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.

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

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

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.

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.. 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 supplements may act as metabolism boosters, help reduce body fat, improve your overall health, and potentially help you decrease your body weight, if you have an underlying deficiency. These work best when combined with other healthy lifestyle choices, like eating a healthy diet and engaging in physical activity

Most of the supplements 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 compounds. Still, some people may be deficient in these components, and supplementing with them in pill form may help boost metabolism and burn calories more efficiently, not to mention improve the overall functioning of your body.

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.

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.

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.

2. Vitamin D

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

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.

Because vitamin D is hard to obtain from foods and many of us don’t get adequate sun exposure, vitamin D deficiency is common. 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.

Calcium helps build strong bones and teeth, plays important roles in the circulatory and neurological systems, and regulates hormones. It also helps regulate metabolism and plays a part in weight management.

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. Another study showed similar results, suggesting an association between calcium and vitamin D supplements and diet-induced weight loss.

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. 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 certain populations lower their BMI and decrease their waist circumference, especially those with hypertension, obesity, magnesium deficiency, and insulin resistance.

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, though the jury is out regarding whether this amount is clinically significant.

Green tea may also play a role in fat oxidation during moderate-intensity exercise and glucose tolerance in certain populations. A small study also showed that it increased metabolism, meaning it helped participants burn more calories throughout the day. 

6. Green coffee extract

Green coffee extract has gained some attention for its potential to support weight loss–early research hints at modest benefits. However, results are inconclusive and more research is needed to determine if the supplement is effective. 

Some side effects of green coffee extract can include upset stomach, headaches, difficulty sleeping, and abnormal heart rhythms. As with any supplement, it's crucial to consult with a healthcare professional before incorporating green coffee extract into your routine, especially if you are sensitive to caffeine.

7. Fiber

Taking a fiber supplement can help with weight loss by making you feel full, which can reduce how much you eat. Soluble fiber, in particular, forms a gel-like substance in your stomach that slows digestion, keeping you satisfied for longer. Studies have found fiber intake to be associated with reduced subsequent calorie intake. Fiber supplements can be a convenient way to increase your fiber intake, but it's important to choose the right one for you and consult with a healthcare professional before adding it to your weight loss plan. Make sure to stay hydrated when taking fiber supplements; without enough water intake, they can have a constipating effect.

8. Protein powder

Your body burns more calories digesting protein than fats or carbs.Protein can also increase satiety, so adding protein powder to your diet may boost your metabolism and help you feel full longer. Protein can help maintain muscle mass while losing weight, which is important for a healthy metabolism, and stabilizes blood sugar to reduce cravings. Choose a protein powder that fits your needs–popular types of protein powder include whey, casein, soy, and plant-based options like pea or hemp protein. Try to avoid protein powder with a lot of added sugar.

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”.

This is why it’s best to review any weight loss supplements you are considering taking with your healthcare provider. Most 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.

If you’re struggling to lose weight and have overweight, obesity, and/or have Type 2 Diabetes Mellitus, consider speaking to a healthcare provider about weight loss medications that are proven to be effective in certain people, like Ozempic or Wegovy. These medications belong to a class of drugs called GLP-1 agonists. They work by increasing feelings of fullness, slowing down the process of stomach emptying, and reducing appetite. Your provider or Ro can help you determine if weight loss medication is right for you.

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Current version

August 22, 2024

Written by

Wendy Wisner

Fact checked by

Raagini Yedidi, MD

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About the medical reviewer

Raagini Yedidi, MD

Raagini Yedidi, MD, is an internal medicine resident and medical reviewer for Ro.