Does vitamin D help us lose more weight?

Posted by Dayne Hudson in Weight Loss

Estimated reading time: 5mins

Does vitamin D help us lose more weight? | Bulk Nutrients blog

What is the best fat loss supplement? Will Vitamin D help?

A recent study in Japan examined 47 top tier college athletes over three months, to see what effects 1,000 IU of vitamin D a day had on fat loss combined with training. Then Covid-19 hit, and the gyms all shut down. 

So, the scientists were left with nothing to examine, and the athletes who were part of the study stopped training.

But here's where it gets interesting: 27 of the athletes kept taking the vitamin D they'd been given. And then, when the three months of the study was up, the researchers took another look at the athletes to see what had happened in the interim.

And they observed that the athletes who didn't take the vitamin D saw an increase in their fat percentage by 1.9 points, while those who did keep taking the supplement only increased their body fat percentage by 0.2 points. And so, the researchers concluded:

"Vitamin D supplementation might have preferable effects on maintaining athletes’ body composition under circumstances where sports activity has decreased.”

Now if you're anything like us, you're immediately asking questions like these: how do we know it was vitamin D that aided the fat loss? How would vitamin D actually help?

The researchers themselves admit the limitations: the athletes weren't randomly assigned to either group, and those who were taking vitamin D might have done more exercise or eaten better. Also, the vitamin D intake was self-reported, meaning some subjects could have been dishonest.

So then what's the truth? 

Vitamin D may help us lose weight.
Vitamin D may help us lose weight.

Will vitamin D help weight loss?

Well, other studies into vitamin D do paint a healthy picture for fat loss:

- In this study, body fat percentages were lower when serum vitamin D levels were higher

- In this research, vitamin D supplementation was found to reduce body fat (a randomised double-blind trial)

- In this meta-analysis, the researchers found a "potential clinical efficacy" when they examined all the vitamin D and fat loss data but do suggest more research is needed.

Whilst there are many factors at play, one of the reasons vitamin D helps us lose fat is by promoting and inducing cellular death in our fat cells. But with randomised controlled trials and meta-analyses suggesting a positive effect on fat loss, the case looks good at this stage for vitamin D supplementation for fat loss. 

Vitamin D for muscle growth?

Here's the wrap sheet for vitamin D and supporting our muscles that may lifters don't know about:

- It helps with their optimal functioning 

- It enhances muscle cell protein synthesis

- It promotes physical capacity, muscle strength and mass

- It promotes endurance by maintaining the optimal level of ATP (the primary carrier of energy in cells)

- It reduces DOMS (delayed onset muscle soreness)

And to add one more to the pile, it's also reported to protect type 2 muscle fibers and shorten our recovery time. And so, we've got you covered with our Bulk Nutrients Vital Pre Mix, which you can conveniently take at any time to reach the daily limit of 4000 IU -- even though 1000 IU was used in the Japanese study.

Bulk Nutrients Vital Pre Mix. "Vitamin D may help you lose weight and support muscle growth."
Bulk Nutrients Vital Pre Mix. "Vitamin D may help you lose weight and support muscle growth."

But there's one caveat with taking vitamin D -- you need to get enough magnesium in your diet to ensure you reap the benefits. Let's bring in some scientists here:

"It is, therefore, essential to ensure that the recommended amount of magnesium is consumed to obtain the optimal benefits of vitamin D."

Ok, so how much magnesium do you need?

Current recommendations are around 420 mg for adult males and 320 mg for adult females. And we've got you covered with our Bulk Nutrients ZMA powder (that contains magnesium), to help you get enough of the mineral to support your vitamin D levels. In fact, you'll get 500 mg of magnesium per serving! 

Moreover, magnesium from your diet will come from foods like green vegetables, seeds, nuts, and unprocessed cereals, along with fruits, fish, meat, and milk products. But when this isn't easy to do, supplementation is the easy option.

The bottom line is that more research may be needed into vitamin D for fat loss, but the evidence we currently have makes supplementation worth it. We need 1000-4000 IU of vitamin D per day, with closer to 4000 IU likely better.

Moreover, for vitamin D to do its job, we need adequate magnesium: 420 mg for adult males and 320 mg for adult females. Vitamin D might not only assist us with more fat loss, but with muscle growth, muscle support, and optimal endurance, too. 


  1. Al Alawi AM, Majoni SW, Falhammar H. Magnesium and Human Health: Perspectives and Research Directions. Int J Endocrinol. 2018;2018:9041694. Published 2018 Apr 16. doi:10.1155/2018/9041694
  2. Arunabh, et al. “Body fat content and 25-hydroxyvitamin D levels in healthy women,” J. Clin. Endocrinol Metab. 2003:88:157-61. 
  3. Kawashima, Itaru, et al. “The impact of vitamin D supplementation on body fat mass in elite male collegiate athletes,: Nutr Metab, 2021, 18:51. 
  4. Khosravi Z.S., Kafeshani M., Tavasoli P., Zadeh A.H., Entezari M.H. Effect of Vitamin D supplementation on weight loss, glycemic indices, and lipid profile in obese and overweight women: A clinical trial study. Int. J. Prev. Med. 2018;9:63. 
  5. Pilch, W., Kita, B., Piotrowska, A. et al. The effect of vitamin D supplementation on the muscle damage after eccentric exercise in young men: a randomized, control trial. J Int Soc Sports Nutr 17, 53 (2020). 
  6. Salehpour, A, et al. “A 12-week double blind randomized clinical trial of vitamin d3 supplementation on body fat mass in healthy overweight and obese women,” Nutr. J. 2012:11:78. 
  7. Uwitonze AM, Razzaque MS. Role of Magnesium in Vitamin D Activation and Function. J Am Osteopath Assoc. 2018 Mar 1;118(3):181-189. doi: 10.7556/jaoa.2018.037. PMID: 29480918.

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