Vitamin D Supplements Can Impact Fertility: True Or False? An Expert Explains

Vitamin D impacts an array of functions in the body—from 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 World Journal of Men's Health that discusses how even erectile function relies directly on vitamin D," and another 2017 study showed that vitamin D was positively associated with sperm motility (or the ability for sperm to swim).* 

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

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.* 

But you don’t just want healthy vitamin D levels during conception, pregnancy, or any other specific time-frame to bump you back up to the sufficient range (a concept Ferira calls “yo-yoing”); you want to maintain healthy vitamin D status for life, and a targeted daily supplement can make that goal a reality.* 

As Ferira declares: "Vitamin D sufficiency doesn't just mean you're meeting a 25(OH)D level or cutoff. It means your bones, muscles, immune cells, brain, heart, liver, gut, reproductive organs, and many more cells, tissues, and organs have this critical nutrient available in adequate quantities to bind to vitamin D receptors and promote calcium and phosphorus balance, bone mineralization, muscle strength, immune function, cardiometabolic health, and more."*