Best Vitamins for Weight Loss

Craig Primack, MD, FACP, FAAP, FOMA

Reviewed by Craig Primack, MD, FACP, FAAP, FOMA

Written by Vanessa Gibbs

Published 04/07/2024

You’ve probably heard that vitamin C can fight off the common cold, vitamin D can help during those long, dark winters and a multivitamin is good for, well, everything. But what are the best weight loss vitamins? Is that even a thing? Are there vitamins for metabolism and vitamins for fat loss?

Let’s set the record straight. While some vitamins might aid you on a weight loss journey, more research is needed to know if they can really help. 

Read on for the science behind these potential weight loss vitamins and alternatives that may be more effective.

More research is needed to find out what vitamins help with weight loss. But here are the vitamins you might want to consider adding to your routine and what we know about them so far.

B Vitamins 

You get bang for your buck with vitamin B complex. That’s a supplement of the B vitamins, which include: 

  • B1 (thiamine)

  • B2 (riboflavin)

  • B3 (niacin)

  • B5 (pantothenic acid)

  • B6 

  • B7 (biotin) 

  • B9 (folic acid) 

  • B12

This group of vitamins may be linked with weight loss. 

A 2023 study on almost 900 people found that when obesity was defined using waist circumference, visceral fat area — belly fat found deep within your abdomen — or body fat percentage, these vitamins were negatively linked to obesity:

  • Vitamin B1 

  • Vitamin B2

  • Vitamin B6

  • Vitamin B9

In simpler terms, low levels of these vitamins were linked to higher levels of obesity. 

There’s also a link between vitamin B12 and obesity. 

Research shows that people with excess weight or obesity have significantly lower levels of vitamin B12 than those with a healthy body weight. Vitamin B12 is also negatively correlated with body mass index (BMI) — the lower the B12, the higher the BMI, and vice versa. 

An important thing to note is you may also be at risk of vitamin B12 deficiency if you take metformin — a diabetes and weight loss drug — for a long time. So whether or not B12 can help you lose weight, it’s important to take a supplement of this vitamin if you take metformin.

The bottom line? It’s unclear whether vitamin B12 supplementation could help with weight management, but it may make it easier. Vitamin B12 is involved in energy production, so a deficiency can lead to fatigue. And low energy levels can make weight loss efforts and, TBH, anything else feel harder.  

So, the link between B vitamins and weight is there, but it’s unclear whether a B vitamin supplement could promote weight loss. More research is needed on that front. 

Vitamin C

Vitamin C may be good for more than just boosting your immune system or acting as an antioxidant. 

Like the B vitamins, vitamin C intake is negatively associated with obesity. 

Does that mean vitamin C supplements could support weight loss? A 2019 study with almost 100 participants with metabolic syndrome suggests that it might.

Participants were split into two groups, both of which took a daily 500 milligram (mg) vitamin C supplement for 12 weeks. The first group only took this supplement, and the second group took the supplement and did 30 minutes of physical activity a day. There were also control groups.

Here’s what the results found: 

  • Both groups taking Vitamin C supplementation had a significant reduction in BMI compared to participants not taking the supplement.

  • People taking Vitamin C and doing physical activity saw a reduction in systolic blood pressure. 

  • This group also saw lowered total cholesterol levels. 

Not bad. 

Vitamin D 

Our bodies make vitamin D when we get sun, but you can also find this vitamin in some foods like fatty fish and, of course, in supplement form.

People with a BMI of 30 or more have lower serum 25(OH)D levels — what vitamin D is first converted into in the body — than those without obesity. 

Having obesity doesn’t necessarily impact how much vitamin D your body makes, but having more subcutaneous fat — the fat found just under the skin — may mean you need more of the vitamin to reach levels of 25(OH)D similar to those that people without obesity have.

And there does seem to be a link between vitamin D levels and certain types of fat loss. 

A 2012 study on 171 participants with excess weight and obesity looked at whether calcium and vitamin D supplementation affected visceral fat.

Participants drank orange juice fortified with 350 mg of calcium and 100 IU of vitamin D three times a day for 16 weeks. 

After 16 weeks of supplementation, the results showed: 

  • Average weight loss didn’t differ significantly between those taking supplements and those not taking supplements. 

  • The group taking the vitamin D and calcium supplements lost more visceral fat. 

While this research looked at a combination of vitamin D and calcium, the researchers concluded that a calcium and/or vitamin D supplement could contribute to visceral fat loss. 

But wait, there’s more. 

Another study, this time from 2013, looked at participants with excess weight and obesity who took 600mg of calcium supplements and 125 IU vitamin D supplements for 12 weeks. They also combined supplementation with an energy-restricted meal plan. 

The key finding? People who took the calcium and vitamin D supplements lost more fat and visceral fat than those who didn't. 

However, this research was on people who consumed very little calcium at the start of the study, so it’s unclear whether calcium supplements could help those who get enough calcium from food sources like dairy products. 

Plus, like with the other vitamins we looked at, we can’t say for sure there’s a link between vitamin D and weight loss. More research is needed, as some studies have found it doesn’t make a difference.

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Weight loss treatment that puts you first

Some promising studies link vitamins to weight loss, but the jury's still out. 

The links between vitamins and weight loss are limited, and vitamins may even cause weight gain. 

Research suggests that B vitamins can promote fat gain. Excess vitamin consumption may also trigger obesity in a few ways, including increasing fat synthesis and causing insulin resistance. 

What’s more, the U.S. Food and Drug Administration (FDA) doesn’t review dietary supplements like vitamins before they go on the market, so there’s no guarantee they’re safe or even have health benefits. If you decide to go the vitamin route, do your research and make sure you buy them from a reputable company.

And even though just reading the word vitamin probably makes you feel healthy, they can still have side effects.   

Our advice? Seek medical advice if you’re considering vitamins for weight loss or for your overall health. A healthcare professional can make sure they’re right for you.

The science is shaky on vitamins for weight loss, but there are other weight loss methods with plenty of research behind them.

You can consider weight loss injections, such as:

  • Ozempic® and Wegovy® (semaglutide) 

  • Mounjaro® and Zepbound® (tirzepatide) 

  • Saxenda® and Victoza® (liraglutide)

And oral weight loss medications, such as: 

  • Metformin

  • Rybelsus® (semaglutide) 

  • Topamax® (topiramate)

  • Qsymia® (phentermine-topiramate)

  • Contrave® (naltrexone-bupropion)

  • Xenical® (orlistat)

Each of these medications comes with pros and cons. Check out our guide to Ozempic vs. metformin to start comparing your options. 

FYI, insurance doesn't usually cover weight loss medications, so they're not an option for everyone. 

Beyond vitamins, some minerals, like calcium and magnesium supplements, and supplements like green tea extract and protein show promise for weight loss. 

Learn more in our guide to the best weight loss supplements for women. 

There are also healthy lifestyle changes you can make to promote weight loss. Whether you choose a vitamin for weight loss, a weight loss medication or no pills or injections at all, these habits are crucial for effective, long-term weight loss.

For healthy weight loss, keep these tips in mind:

  • Eat a healthy diet with nutritious foods, including fruits, veggies, whole grains and healthy snacks

  • Incorporate more movement into your day. 

  • Get enough sleep. 

  • Drink more water. 

  • Get support with behavioral change and building new habits. 

So, you wanna lose weight, and you’re looking for vitamins to help. Research shows that some vitamins are linked to weight loss, but it’s not as straightforward as popping a pill. 

Here’s the key info: 

  • B vitamins, vitamin C and vitamin D show promise. Low vitamin C and some B vitamins are linked with obesity. Some studies show supplementation of vitamins C and D can reduce BMI and fat loss, respectively. 

  • The science is lacking. More research is needed into key questions, like: Does vitamin B help you lose weight? How much vitamin C and D are needed for weight loss? And are there other vitamins linked to obesity?

  • Vitamins are just one piece of the puzzle. Even if they are effective, you'll want to make other lifestyle changes to achieve your weight loss goals, like following a healthy eating plan, adding more movement into your day and getting plenty of sleep. 

Talk to a healthcare provider or dietitian if you're considering adding a vitamin to your daily routine. 

They can let you know if it’s safe for you to do so, taking into account any medication you take or health conditions you have. They can also let you know if you’re getting enough vitamins from food sources. 

And if you’re looking into weight loss treatments, know that plenty of options out there have been proven to help.

12 Sources

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  2. Fu, Y., Zhu, Z., Huang, Z., He, R., Zhang, Y., Li, Y., Tan, W., & Rong, S. (2023). Association between Vitamin B and Obesity in Middle-Aged and Older Chinese Adults. Nutrients, 15(3), 483. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9921635/
  3. Baltaci, D., Kutlucan, A., Turker, Y., Yilmaz, A., Karacam, S., Deler, H., Ucgun, T., & Kara, I. H. (2013). Association of vitamin B12 with obesity, overweight, insulin resistance and metabolic syndrome, and body fat composition; primary care-based study. Medicinski glasnik : official publication of the Medical Association of Zenica-Doboj Canton, Bosnia and Herzegovina, 10(2), 203–210. https://www.researchgate.net/publication/253335225_Association_of_vitamin_B12_with_obesity_overweight_insulin_resistance_and_metabolic_syndrome_and_body_fat_composition_primary_care-based_study
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  6. Farag, H. A. M., Hosseinzadeh-Attar, M. J., Muhammad, B. A., Esmaillzadeh, A., Bilbeisi, A. H. E. (2019). Effects of vitamin C supplementation with and without endurance physical activity on components of metabolic syndrome: A randomized, double-blind, placebo-controlled clinical trial. Clinical Nutrition Experimental. 26, 23-33. https://www.sciencedirect.com/science/article/pii/S2352939319300260
  7. Vitamin D. (2023). https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
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