This paper will aim to review the current evidence of clinical effects of testosterone treatment within an aging male population. Epidemiological studies suggest that many significant clinical findings and important disease states are linked to low testosterone levels. The link between testosterone and longevity is still being explored, but early findings suggest that optimal testosterone levels may be a cornerstone of healthy aging for men. That’s when we start to check your hormone levels," McDevitt says. You may become pre-diabetic, or see your cholesterol levels rise, says Danielle McDevitt, M.D., a physician who specializes in hormones. Testosterone is a hormone that’s crucial for men’s health. A guy in his 20s with healthy genes and no chronic ailments will have a higher testosterone level than a 55-year-old with ongoing medical issues. It helps men develop during puberty, and as they age, it plays a critical role in helping control fat levels, cholesterol, and glucose levels (1). The use of beta blockers to manage the side effects of other drugs highlights the physiological strain of such a protocol. But if you have a deficiency, T therapy can restore vitality and may help motivate you to do the workouts that will build muscle strength and mass. "It just makes the muscle fibers that remain bigger," says Dr. Anawalt, and it’s not certain that this has age-reversing benefits. Yet even without symptoms, men are clamoring to replace that age-related loss, because why wouldn’t you want your level to be the same at 60 as it was at 30? A man’s testosterone level drops about 1 to 2 percent a year, starting around age 40. In this model, increases in body fat lead to increases in aromatase levels, in addition to insulin resistance, adverse lipid profiles and increased leptin levels. Further explanation of the links between hypogonadism and obesity is offered by the hypogonadal-obesity-adipocytokine cycle hypothesis (see Figure 1). This effect can be explained by the action of testosterone in inhibiting lipoprotein lipase and thereby reducing triglyceride uptake into adipocytes (Sorva et al 1988), an action which seems to occur preferentially in visceral fat (Marin et al 1995; Marin et al 1996). Testosterone also produced a significant reduction in insulin resistance, measured by the homeostatic model assessment (HOMA), in the fourteen non-insulin treated patients. Testosterone treatment led to a significant reduction in glycated hemoglobin (HbA1C) and fasting glucose compared to placebo. It was found that physiological treatment doses led to improved insulin resistance, as measured by the gold standard technique using a euglycemic clamp and/or serum glucose and insulin responses during glucose tolerance test. This analysis can supply evidence of the likely effects of testosterone on overall cardiovascular risk. No trial of sufficient size or duration has investigated the effect of testosterone replacement in primary or secondary prevention cardiovascular disease. A 4-year follow up study of the latter population showed that free testosterone was also inversely correlated with the rate of increase of IMT (Muller et al 2004). Epidemiological studies have also assessed links between serum testosterone and non-coronary atherosclerosis. In vitro studies have shown that leptin also inhibits testosterone production directly at the testes. His doctor said he was fine and didn't need hormone replacement therapy. His levels were "low-normal," or in the lower 50% of the reference range. When he first suspected low testosterone, Kaeberlein saw his primary care physician. The development of hypogonadism with aging is known as late-onset hypogonadism and is characterised by loss of vitality, fatigue, loss of libido, erectile dysfunction, somnolence, depression and poor concentration. Increases in the amount of testosterone converted to estrogen under the action of the enzyme aromatase may also contribute to hypogonadism. The extent to which testosterone deficiency is involved in the pathogenesis of these conditions, or to which testosterone supplementation could be useful in their treatment is an area of great interest with many unanswered questions. This raises the question of whether some symptoms of aging could be due to relative androgen deficiency. The symptoms of aging include tiredness, lack of energy, reduced strength, frailty, loss of libido, decreased sexual performance depression and mood change. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations. An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men.
