Personal care products sitting right in your bathroom and kitchen cabinets could be lowering your testosterone levels, and a new study has found how exposure is affecting our organs and tissues. Researchers from the University of Michigan School of Public Health published their findings in the Journal of Clinical Endocrinology & Metabolism.

In the last 50 years, there’s been a decline in men’s testosterone levels and a rise in health conditions that relate to low levels, including reduced semen quality, and genital malformations in newborn boys. "We found evidence reduced levels of circulating testosterone were associated with increased phthalate exposure in several key populations, including boys ages 6 to 12, and men and women ages 40 to 60," the study's co-author, John D. Meeker, of the University of Michigan School of Public Health, said in a press release. "This may have important public health implications, since low testosterone levels in young boys can negatively impact reproductive development, and in middle age can impair sexual function, libido, energy, cognitive function, and bone health in men and women."

Phthalates are a type of chemical that make plastics more flexible but durable, and are found in detergents, vinyl flooring, adhesives, lubricating oils, raincoats, and various soaps, shampoos, hair sprays, and nail polishes, according to the Centers for Disease Control and Prevention (CDC). The constant exposure to the chemical has been known to lower testosterone levels, which are responsible for physical growth and strength, brain function, bone density, and cardiovascular health.

More than 90 percent of men with low testosterone levels do not seek treatment, and among them, 70 percent will have trouble maintaining erections, and 63 percent will have a low sex drive, according to EverydayHealth. While the physical impacts of a low sex drive can cause emotional fluctuations, such as feelings or sadness, depression, and low self-confidence, the inability to reproduce can alter the course a man and his partner’s life who must find alternative routes to achieve a successful and healthy birth.  

After analyzing testosterone levels and their relationship to phthalates in 2,208 participants from the U.S. National health and Nutrition Examination Survey between 2011 to 2012, they found 13 different substances in their urine. When they looked at each of their blood samples, those participants also had a 24 to 34.1 percent drop in testosterone levels. In the past, CDC researchers have found phthalates in the urine of 2,636 participates who were 6 years or older between 1999 and 2002, and found enough to conclude there was a widespread exposure in the U.S. population.

"While the study's cross-sectional design limit the conclusions we can draw, our results support the hypothesis that environmental exposure to endocrine-disrupting chemicals such as phthalates could be contributing to the trend of declining testosterone and related disorders," Meeker said. "With mounting evidence for adverse health effects, individuals and policymakers alike may want to take steps to limit human exposure to the degree possible."

Source: Meeker JD and Ferguson KK. Urinary Phthalate Metabolites are Associated with Decreased Serum Testosterone in Men, Women and Children from NHANES 2011-2012. Journal of Clinical Endocrinology & Metabolism (JCEM). 2014.