Testosterone (CAS 58-22-0) is a hormone that regulates a number of processes in the human body. In males, testosterone is secreted by the testes while in women it is secreted by the adrenal glands and ovaries, with some being made up through the peripheral conversion of another hormone, androstenedione.

Most testosterone is not freely available in the bloodstream, but is rather bound to either albumin or to sex hormone binding globulin (SHBG). Unbound testosterone and that bound to albumin are said to be active and bio-available, while testosterone bound to SHBG is unavailable and unable to perform its function.

The Function of Testosterone

Testosterone has a large number of functions both in males and in females, and a change in testosterone levels in the body can have profound effects. A low testosterone count can have the following effects:

● Delayed puberty in adolescents

● Hypogonadism in boys

● Testicular failure in adult males

● Erectile dysfunction in men

● Infertility in both men and women

Having an accurate count of testosterone levels for patients with these symptoms can be key in forming the correct diagnosis.

Testing for Testosterone

There are three testosterone measurements that are usually taken: the total testosterone, the free testosterone levels and the amount of bio-available testosterone.

Total testosterone levels are measures by mass spectrometry. This technique has the benefit of being rapid (analysis of a sample can take as little as four minutes) and has a very high sensitivity and specificity, with no cross-reactivity to other steroid compounds. The reportable range is very large, and encompasses the limits of human testosterone levels.

Free testosterone levels are measured through equilibrium dialysis which gives the percentage of free testosterone. The technique can be used to investigate the amount of protein bound to specific ligand, and then calculate the percentage of unbound ligand from that. The amount of free testosterone is then calculated from the total testosterone level found through LC/MS/MS.

Finally, the amount of bio-available testosterone can also be calculated from the constants for the binding of testosterone to SHBG through an immunochemiluminometric assay or the binding to albumin through spectrophotometry.

Complete testosterone data sets can help doctors form a diagnosis in the event of the symptoms described above. However, a number of factors can increase or decrease testosterone levels, such as drug use, and these should be considered as well.

In order to complete these tests analysis labs rely heavily on mass spectrometry for accurate analysis at trace content. As such IsoSciences synthesizes and has available both labeled and unlabeled forms of testosterone.

6066UNL unlabeled testosterone (unlabeled)

6066 13C-labeled Testosterone (13C3)

3009 D-labeled testosterone (D5)

These testosterone solutions are available as CertiMass solutions in order to increase efficiency of testing if that is required.

We are proud to offer a selection of stable labeled hormones. For your convenience, we sell unlabeled hormones alongside our list of labeled hormones. Our selection includes CertiMass™ Reference Standards, which are standard solutions for many of our premier compounds

If you are unable to find the desired hormone in our catalog, please contact us by email or phone (610-337-3762) we will be more than happy to provide a quote on custom synthetic work.