Total Testosterone
The primary male sex hormone responsible for muscle mass, bone density, red blood cell production, and sex drive.
What It Measures
The total amount of testosterone in your blood, both bound and unbound.
Reference Range
Optimal levels for men are typically 500-900 ng/dL, though labs list 250-1100 as the normal range.
If High
May indicate steroid use, tumors, or hyperthyroidism. Can cause aggression, acne, and sleep apnea.
If Low
Can cause fatigue, low libido, erectile dysfunction, depression, loss of muscle mass, and increased body fat.
Panels That Include Total Testosterone
Scientific References
Longitudinal effects of aging on serum total and free testosterone levels in healthy men. Baltimore Longitudinal Study of Aging
Harman SM, Metter EJ, Tobin JD, Pearson J, Blackman MR. J Clin Endocrinol Metab (2001); 86(2):724-731.
PMID: 11158037Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts Male Aging Study
Feldman HA, Longcope C, Derby CA, et al.. J Clin Endocrinol Metab (2002); 87(2):589-598.
PMID: 11836290Effects of testosterone treatment in older men
Snyder PJ, Bhasin S, Cunningham GR, et al.. N Engl J Med (2016); 374(7):611-624.
PMID: 26886521