In one pilot study, CoQ10 supplementation in men with asthenozoospermia (poor seminal motility) appeared to be somewhat effective at improving seminal motility, though not sperm count or sperm morphology,[1] while another study also noted an increase in sperm density with CoQ10 supplementation.[2]
Additionally, one study involving men with a low fertilization rate in an infertility clinic reported an increase in fertility when taking 60 mg of CoQ10 daily for 103 days before in vitro fertilization, suggesting an improvement in sperm function.[3] Moreover, in another study, 200 mg of COQ10 daily for 6 months improved sperm motility in men, leading to increased fertility, with 3 out of 22 couples achieving spontaneous pregnancy within 3 months of the discontinuation of therapy.[1]