New Study Raises Testosterone Normal Limit

New normal range of testosterone raised to 348-1197 ng/dl from 241-827 ng/dl

What is considered a “normal” testosterone level in men has just changed. A new study published in The Journal of Clinical Endocrinology and Metabolism (1) is causing medical laboratories to reconsider what should be considered normal. Effective October 17th, 2011, the testosterone serum reference interval for adult males will be raised to 348-1197 ng/dl at Labcorp as a result of this study, and other testing labs are sure to follow.

The “old” normal range was based on what was typical for 95% of the population. That population sample thus included the elderly and very ill. Judging the testosterone level of an otherwise healthy 50-year-old male against a standard that included 85-year-old diabetic cancer patients with heart disease was obviously not in the 50-year-old’s best interests.

This new study above used 456 healthy men from 19 to 40 years of age to generate the reference data for a much more realistic ‘normal’ range. The median value for Total Testosterone in this study was 698.7 ng/dl. The new “low” figure generated by this study and adopted by Labcorp is now 348 ng/dl. Our optimal target range for males is 650 ng/dl and up.

Low hormone levels have been shown throughout published scientific literature to be positively associated to many of the disease states associated with aging; including Cardiovascular Disease, Cancer, Stroke, Diabetes, Dementia, and Arthritis. Our focus has always been on bringing hormone levels up to the ‘optimal’ range to prevent the onset of these disease states and/or treat them after the fact.

The study goes on to show distinct correlations between low total testosterone / low free testosterone and the onset of sexual symptoms, physical dysfunction and diabetes. This is a very comprehensive, scientifically significant study that tracked three generations of men starting in 1948.

Download the attached PDF of the complete article.