When Testosterone Levels Fall Short

Low testosterone in men

Testosterone deficiency in men can affect several aspects of health. Sexual symptoms, including reduced libido, fewer spontaneous or morning erections and erectile dysfunction, are among the more specific symptoms. Other possible features include fatigue, reduced muscle mass and strength, low mood and reduced bone density.

However, these symptoms are not unique to testosterone deficiency and can have many other causes. A diagnosis of hypogonadism therefore requires symptoms alongside appropriate biochemical testing rather than being based on symptoms or a single testosterone result alone.

Testosterone in women

Women also produce testosterone, although circulating concentrations are considerably lower than in men. Testosterone and other androgens contribute to normal female physiology, including sexual function.

Unlike in men, however, there is no well-defined blood testosterone concentration that can be used to diagnose a generalised “testosterone deficiency” syndrome in otherwise healthy women. Symptoms such as fatigue, low mood or difficulty building muscle are non-specific and should not automatically be attributed to low testosterone.

Free testosterone measurements can instead be particularly useful when investigating androgen excess in women. High androgen levels may be associated with symptoms such as increased facial or body hair, acne, scalp hair thinning and irregular menstrual cycles. Polycystic ovary syndrome (PCOS) is the most common cause of androgen excess in women.