Study Links Tight Underwear to Lower Semen Quality and Sexual Dysfunction
A major study from China links tight underwear to reduced semen quality and sexual dysfunction, pointing to increased scrotal temperatures as a potential contributing factor.
A comprehensive study conducted in China among 26,836 men seeking fertility evaluations at the First Affiliated Hospital of the University of Science and Technology of China has renewed the long-standing debate regarding men's underwear choices.
The findings, published in the Asian Journal of Andrology, indicate a correlation between wearing tight underwear and a decline in semen parameters alongside an increase in reported sexual dysfunction.
Researchers compared 21,221 men who reported wearing loose underwear, such as boxers, with 5,615 men who preferred tight underwear, such as briefs or thongs, in the three months preceding the examination.
According to the analysis, men who wore tight underwear exhibited lower semen quality, including a reduced semen volume, a smaller count of motile sperm, and a 48% lower rate of morphologically normal sperm. Furthermore, researchers observed a twofold increase in the prevalence of sperm DNA fragmentation, recording 10.7% in the tight underwear group compared to just 5.8% in the loose underwear group.
The study also pointed to a higher prevalence of erectile dysfunction and premature ejaculation among wearers of tight underwear. The researchers hypothesized that prolonged tight clothing might also negatively impact testosterone secretion, though they emphasized that this finding is preliminary and requires cautious interpretation.
The Mechanism: Scrotal Temperature Increase
Researchers explain that the suspected mechanism behind the impairment is an elevation in scrotal temperature. Normal sperm production requires an environment about 2 to 3 degrees Celsius cooler than core body temperature. Tight clothing reduces ventilation and raises local heat by half a degree to a full degree Celsius—a small difference, yet one sufficient to disrupt the final stages of sperm maturation.
Nevertheless, the study authors qualified their findings by clarifying that the research is observational and direct causality was not proven, meaning it cannot be definitively established that tight underwear directly caused the decline in sperm quality. Additionally, because the study relied entirely on men already seeking fertility evaluations, medical experts note that the results may not necessarily apply to the general population.
According to specialists, although many doctors advise men trying to conceive to avoid tight clothing as a precautionary measure, further research is required to determine whether switching to loose underwear actually improves pregnancy rates in practice.
