We stand with Ukraine. 🇺🇦

Testosterone free

SI UNITS (recommended)


* The SI units is the recommended method of reporting clinical laboratory results

Free Testosterone, Testosterone Direct
Units of measurement
pmol/L, pg/mL, pg/dL, pg/100mL, pg%, pg/L, ng/L

Testosterone is a pleiotropic hormone, meaning it affects different phenotypes and plays an important role in the human body. It is a C19-steroid and the most effective natural hormone in the family of androgens. Testosterone in men is produced by the testes as well minimally by the adrenal cortex. In women testosterone derives from the production in the adrenal cortex and ovaries, accounting for 50 % of testosterone, while the remainder is produced from peripheral tissues such as bone, breast, muscle, and fat.

Like other steroid hormones, testosterone concentrations follow a diurnal rhythm, with testosterone levels peaking in the morning and declining during the day. Roughly 1 - 5 % of free testosterone are present in serum of healthy individuals with 38 % albumin-bound testosterone, and 60 % sex hormone-binding globulin (SHBG)-bound testosterone; where the latter two are typically unable to enter the intracellular environment and exert their biochemical effects. To determine the level of testosterone, it is relevant to measure the free fraction because it is biologically active and it can be performed in bodily fluids like plasma or serum.

Measuring testosterone plays a vital role in the diagnosis of different endocrine disorders. An increased  testosterone level can be due to testicular or pituitary abnormalities or androgen abuse in men.  

A decline in hormone production including testosterone can be observed in aging men who experience a variety of symptoms with declining testosterone levels e.g. thinning hair, loss of vigor or sexual dysfunction. Measurement in women is applied as an aid to diagnose clinical hypogonadism and to help diagnose hyperandrogenic states e.g., hirsutism, ovarian failure and infant congenital adrenal hyperplasia, ovarian or adrenal neoplasm, polycystic ovarian syndrome. 

SI units Conversion Calculator. Convert Testosterone free level to pmol/L, pg/mL, pg/dL, pg/100mL, pg%, pg/L, ng/L. Clinical laboratory units online conversion from conventional or traditional units to Si units. Table of conversion factors for Testosterone free unit conversion to pmol/L, pg/mL, pg/dL, pg/100mL, pg%, pg/L, ng/L.