Testosterone

Declining testosterone levels in men over 45 is common¹ and is often the cause of erectile dysfunction (ED). Androgen deficiency, or hypogonadism, affects roughly 40% of men aged 45 or older.²

Two-thirds of these men present with symptoms. While some symptoms, like ED, indicate deficiency, additional symptoms can be similar to those of other diseases, such as cardiovascular disease.² Tests for free, bioavailable, and total testosterone are essential to help diagnose hypogonadism and rule out other conditions. For those who may be candidates for testosterone therapy, as well as for those already on therapy, testing can also help assess and monitor testosterone levels.

Male hypogonadism is a clinical syndrome that results from failure of the testes to produce physiological levels of testosterone (androgen deficiency) and a normal number of spermatozoa due to disruption of one or more levels of the hypothalamic-pituitary-testicular (HPT) axis.

There are 3 types of hypogonadism³:

• Primary—testicular dysfunction leads to low levels of testosterone and high levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH)
• Secondary—dysfunction of the HPT axis results in low levels of testosterone, LH, and FSH
• Mixed—manifests a mixture of primary and secondary hypogonadism and can be observed in older men

Endocrine Society guidelines recommend testing patients who present with symptoms of androgen deficiency.³

Some symptoms include³:

• Reduced sexual desire (libido) and activity
• Breast discomfort (gynecomastia)
• Loss of body (axillary and pubic) hair, reduced shaving
• Very small or shrinking testes
• Inability to father children, low or zero sperm count
• Height loss, low trauma fracture, and/or low bone mineral density
• Hot flushes and sweats
• Decreased energy, motivation, initiative, and self-confidence
• Poor concentration and memory
• Reduced muscle bulk and strength
• Increased body fat

The more symptoms a patient has, the more likely he is to have low testosterone.

Women can be affected by testosterone levels as well. Hyperandrogenism is characterized by excess production of androgens by the ovaries and/or the adrenal glands.

The most common clinical manifestation of hyperandrogenism is hirsutism, or excessive terminal hair growth in androgen-dependent areas of the body. Other clinical manifestations of hyperandrogenism include acne vulgaris, weight gain, menstrual irregularities, and, in some women with polycystic ovary syndrome (PCOS), acanthosis nigricans.