In addition, if you are planning fertility, you should not use testosterone therapy. There are many different types of testosterone therapy. These should be addressed before testosterone therapy is contemplated. This might include additional blood tests, and sometimes imaging such as a pituitary MRI. When sex hormone-binding globulin (SHBG) is abnormal, total testosterone measurement may not accurately assess the true biological effects of testosterone, or ‘androgenicity’. Weight loss is a highly effective way of increasing testosterone levels in men with obesity, just like testosterone treatment. Society for Endocrinology guidelines for testosterone replacement therapy in male hypogonadism have recently been published in Clinical Endocrinology.1 Here, guideline working group members Channa N Jayasena and Richard Quinton discuss some of the topical issues that they addressed in developing the guidelines. The measures can help maintain normal testosterone levels. Likewise, measurement of symptoms alone is not reliable, as hypogonadal symptoms are non-specific. In the Baltimore Longitudinal Study on Ageing, it was found that 19% of men over 60 years had low testosterone. This is found in men with sickle-cell disease, thalassemia, alcoholism, glucocorticoid treatment, and in older men (2). Target cells that contain 5α-reductase are concentrated in the prostate, reproductive system and skin. Approximately 20% of the DHT in the circulation is produced directly by testicular secretion, with the remaining 80% being derived from conversion from testosterone in the peripheral tissues (10). An age-related guideline for referral if PSA levels exceed 2.5 ng/ml in males under 60 years or 4 ng/ml in men over 60 years is often used (97). However, recent analysis has shown that, although there are case studies of occult conversions, these represent a very small number of the 200,000 cases of prostate cancer diagnosed in the United States and there is no evidence of causality. Case reports of occult cancers apparently stimulated to become clinically relevant cancers by testosterone treatment added to the concern. The origins of this concern date back to papers published in 1941 that reported that androgens stimulated prostate cancer, whereas oestrogen or castration reduced them (91). Many people shrug off the symptoms linked with low testosterone as an unpleasant part of getting older. Low testosterone may lead to weak bones (osteoporosis) or heart and blood vessel disorders. If you’re taking hormone replacement therapy, you’ll need regular follow-up visits with a healthcare provider. If you have symptoms of low testosterone, talk to a healthcare provider. Although the normal range for serum testosterone might vary between different laboratories, the normal range for early morning total testosterone in healthy adult males is approximately 300 ng/dL to 1000 ng/dL.7,8 In males, serum testosterone levels show a circadian variation, with the highest levels in the morning and lowest levels in the late afternoon. Hypogonadism is a lack of testosterone in male patients and can be of central (hypothalamic or pituitary) or testicular origin, or a combination of both. Data from the MMAS have demonstrated that there is a strong, positive relationship between HDL and testosterone in men with cardiovascular disease (low total or free testosterone correlates with low HDL cholesterol) (31). The relationship between testosterone and HDL is confounded by the fact that both HDL and testosterone are inversely related to BMI. However, when given as a transdermal gel to hypogonadal men, there is either no significant change or only minor changes in HDL levels (28,31,32). Vascular tissue (including endothelium and vascular smooth muscle cells) contains androgen receptors, so it is to be expected that testosterone (or its metabolite, oestrogen) is likely to affect the cardiovascular system. There appears to be no consistent evidence that the prevalence of hypogonadism differs between racial and ethnic groups (24–26). An interesting observation from the MMAS was that half of the men found to have symptomatic androgen deficiency at one stage were found to be eugonadal when retested at a later stage (22).
