Testosterone (Total)

What is Testosterone (Total)?

Total testosterone includes both protein-bound testosterone (about 98% — bound to SHBG and albumin) and free testosterone (about 2% — biologically active). In men, testosterone is primarily produced by Leydig cells in the testes; in women, by the ovaries and adrenal glands. Testosterone drives muscle mass, bone density, libido, mood, and red blood cell production.

What might a high or low Testosterone (Total) mean?

Low testosterone in men (hypogonadism) causes fatigue, decreased libido, muscle loss, increased body fat, depression, and osteoporosis. Testosterone levels naturally decline 1-2% per year after age 30. However, total testosterone can be misleading when SHBG is abnormal — always check free testosterone or calculate it alongside SHBG.

What is the typical reference range for Testosterone (Total)?

The general-population reference range shown here is 8.6 – 29 nmol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.

What can affect Testosterone (Total)?

It may be higher with: Resistance training (compound lifts), Adequate sleep (7-9 hours), Weight loss (in obese men), Zinc supplementation (if deficient), Vitamin D optimization, Reducing chronic stress, Testosterone replacement therapy (TRT), Clomiphene or hCG. It may be lower with: Aging (1-2% per year after 30), Obesity (aromatase converts T to estrogen), Chronic stress (cortisol suppresses GnRH), Sleep deprivation, Opioid medications, Excessive alcohol, Endurance overtraining, Type 2 diabetes and metabolic syndrome.