Vitamin D Supplements Can Affect Fertility: True Or False?

Vitamin D affects an array of functions in the body—immunity, neurological function, cardiometabolic health, and more.* It only makes sense that this essential, multitasking micronutrient would have a stake in fertility as well. And not just for women—male fertility is becoming a hot discussion, after all (we even wrote a whole Wellness Trend about it!), and vitamin D supplementation can play a large role in men's reproductive function.*

Just take it from mbg's director of scientific affairs, Ashley Jordan Ferira, Ph.D., RDN: On the mindbodygreen podcast, she calls vitamin D and fertility a very leading-edge (and promising) area of research.  

The field is still growing, says Ferira, but the available research we do have looks pretty compelling. In terms of male fertility: "It turns out the quality of semen and the ability of sperm to swim is dependent on vitamin D status,"* she notes. "There was a 2021 study in the 1World Journal of Men's Health1 that discusses how even erectile function relies directly on vitamin D," and another 2017 study showed that vitamin D was positively associated with sperm motility2 (or the ability for sperm to swim).* 

As for women, research shows vitamin D deficiency may impact fertility outcomes in women3 (and for what it's worth, almost half the population4 of the U.S. is insufficient and almost one-third are deficient5). Plus, vitamin D status is important during pregnancy: Healthy levels are linked to babies' birth weight, healthy teeth, and cognition6.*

Vitamin D insufficiency and deficiency are pretty common in this country (and worldwide), and you can always test your own blood levels with a 25(OH)D lab (if it reads less than 30 ng/ml, that means you're clinically insufficient). Meanwhile, the solution to correct inadequate vitamin D status in this nation (and globally) is not elusive.

Science and clinical expertise indicate that a 25(OH)D level of 50 ng/ml plus is the optimal goal for sufficiency, which is difficult to achieve through food and sunshine alone—that's where high-quality vitamin D3 supplements come into play; specifically, the latest research suggests 5,000 IU of D3 per day is the most effective supplement dose.* 

This fat-soluble vitamin is that whole-body relevant and important on the daily.* The link between vitamin D and fertility is a growing one, but vitamin D is crucial for so many functions in the body—including, yes, your reproductive organs.* That said, a healthy vitamin D status can support key aspects of both female and male fertility, and we believe the most effective way to reach that goal is with a daily supplement.*