Male Infertility: Can Vitamin D Improve Pregnancy Success?

Consider this scenario: You and your partner are ready to start a family. However, after a year of failed attempts to conceive, you decide to visit a fertility specialist to determine what is preventing your family from growing. The tests come back. You or your partner are diagnosed as infertile.

Unfortunately, this is the reality that over 5 million people face within the United States alone. In addition, according to a new study, male infertility is on the rise. Researchers from this study found sperm counts have declined by nearly 60% over the last 40 years among European, North American and Australian men.

Vitamin D And Pregnancy

Vitamin D has developed a reputation for benefiting sexual health; however, is there any merit behind the puns? It turns out, there is.  Research suggests vitamin D status indeed plays an important role in reproductive health. In fact, vitamin D status has been linked with sexual function,  testosterone levels and fertility. In addition, studies have found vitamin D deficiency is more prevalent among men with low semen production, quality and motility, along with lower inhibin B levels.

Embryologist Kez Emeny explained the relevance of inhibin B status on male fertility:

“Inhibin B levels reflect testicular function and Sertoli cell function. Inhibin B levels are reduced in men with infertility problems compared with fertile men. Studies show that inhibin B levels are a more sensitive marker of male factor infertility than other hormones.”

RCT Evaluates Relationship Between Vitamin D And Male Fertility

In an effort to determine whether vitamin D supplementation may improve semen quality and hormonal imbalances among infertile men, researchers from Denmark conducted a triple blinded, randomized controlled trial. Men were included in the study if they were part of a couple diagnosed with infertility due to impaired semen quality, had vitamin D levels below 20 ng/ml (50 nmol/l) and did not have any serious secondary diseases.

Vitamin D3 For Men

A total of 307 individuals participated in this study. The participants provided two semen samples for analysis, as well as received a blood draw at baseline. The men were randomly assigned to either receive a single dose of 300,000 IU vitamin D3 along with a daily dose of 1,400 IU vitamin D3 and 500 mg of calcium for 150 days, or receive two received a single oil based placebo, followed by a placebo pill for 150 days.

Here is what the researchers found:

  • Average baseline vitamin D status was 14 ng/ml (35 nmol/l).
  • The vitamin D group experienced a 17.2 ng/ml (43 nmol/l) increase in 25(OH)D compared to the 2 ng/ml increase in the placebo group (p < 0.001).
  • There were no cases of vitamin D toxicity.
  • A total of 7.3% of the couples in the vitamin D group achieved pregnancy without assistance from physician; whereas only 2.4% became pregnant in the placebo group.
  • In a subgroup analysis of men with low sperm count (oligozoospermia), the chances of a live birth increased to 35.6% in the vitamin D group, compared to 18.3% in the placebo group (p = 0.04).
  • Serum inhibin B levels were 49 pg/ml higher among the vitamin D group compared to the placebo group (p = 0.021).
  • Serum inhibin B/FSH ratio changes were positively associated with changes in vitamin D status over the 5-month period (p = 0.038).
  • Sperm count tended to be higher in the vitamin D group compared to the placebo group, though this did not reach significance (p = 0.07).

Vitamin D And Pregnancy: Summary

Due to the safety of vitamin D supplementation, along with its proven impact on reproductive health among both men and women, the team at Aria Integrative Health recommends supplementing with 5,000-10,000 IU (125- 250 mcg) of vitamin D3 per day in order to maintain optimal status (40-60 ng/ml; 100-150 nmol/l).

We offer a range of services in regards to optimizing reproductive health and sexual function in both men and women. Contact us to learn how we can help ensure your health needs are being met!


Jensen, M., MD. et al. Effects of vitamin D supplementation on semen quality, reproductive hormones and live birth rate: a randomized clinical trial. The Journal of Clinical Endocrinology & Metabolism, 2017.

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