From the publication:

In conclusion, thus far the studies conducted on human males generally reveal an insignificant effect of coenzyme Q10 supplementation on testosterone levels. Similarly, the studies conducted on animals, rather than the reproductive toxicity studies, did not show positive effectiveness of coenzyme Q10 on testosterone. However, coenzyme Q10 supplementation was found to counteract testosterone reduction induced by chemical reproductive toxicants, mainly by counteracting the destructive effect of the generated pro-oxidants. In addition, according to the peer-reviewed literature in this specific context of research, studies performed on human males have revealed no beneficial effects of coenzyme Q10 supplementation on infertile men. Thus, dietary supplements containing much lower doses may not have any influence on the studied subjects.