In a recent and very large study , reports show that levels of testosterone in the U.S. are dropping at a steady rate.To show a small example , average total testosterone levels in men age 65 to 70 fell from 500 nanograms/decileters in 1988 to 420 ng/dL in the year 2003.

“Male serum testosterone levels appear to vary by generation, even after age is taken into account,” study lead author Thomas G. Travison said in a prepared statement. Experts say that although it is normal for a man’s testosterone levels to peak during the age of 20 and mid 20’s , the levels of testosterone found in the studies show that the testosterone levels are actually lower than they were 20 years ago.

“In 1988, men who were 50 years and older had higher serum testosterone concentrations than did comparable 50-year-old men in 1996. This suggests that some factor other than age may be contributing to the observed declines in testosterone over time,” Travison said.

Precise reasons for the decline of testosterone is not certain , however certain aspects can be factored in such as obesity , alcoholism , smoking and other health hazards. Testosterone is responsible for maintaining healthy bones , muscle mass , fighting depression and a variety of benefits. Low levels of testosterone has been linked to health problems including a non existant sex drive and even diabetes.

The findings were published in the Journal of Clinical Endocrinology and Metabolism.