^ Butenandt A, Hanisch G (1935). "Umwandlung des Dehydroandrosterons in Androstendiol und Testosterone; ein Weg zur Darstellung des Testosterons aus Cholestrin" [About Testosterone. Conversion of Dehydro-androsterons into androstendiol and testosterone; a way for the structure assignment of testosterone from cholesterol]. Hoppe-Seyler's Z Physiol Chem (in German). 237 (2): 89–97. doi:10.1515/bchm2.1935.237.1-3.89.
Exercise boosts testosterone in two important ways. First, specific types of exercise actually cause our body to produce more testosterone. We’ll talk more about those in a bit. Second, exercise helps to increase muscle mass and decrease body fat. As we’ve discussed previously, adipose tissue converts testosterone into estrogen. The less fat we get, the more T we have.
Testosterone levels generally peak during adolescence and early adulthood. As you get older, your testosterone level gradually declines — typically about 1 percent a year after age 30 or 40. It is important to determine in older men if a low testosterone level is simply due to the decline of normal aging or if it is due to a disease (hypogonadism).
Cross-sectional studies have not shown raised testosterone levels at the time of diagnosis of prostate cancer, and in fact, low testosterone at the time of diagnosis has been linked with more locally aggressive and malignant tumors (Massengill et al 2003; Imamoto et al 2005; Isom-Batz et al 2005). This may reflect loss of hormone related control of the tumor or the effect of a more aggressive tumor in decreasing testosterone levels. One study found that 14% of hypogonadal men, with normal digital rectal examination and PSA levels, had histological prostate cancer on biopsy. It is possible that low androgen levels masked the usual evidence of prostate cancer in this population (Morgentaler et al 1996). Most longitudinal studies have not shown a correlation between testosterone levels and the future development of prostate cancer (Carter et al 1995; Heikkila et al 1999; Stattin et al 2004) but a recent study did find a positive association (Parsons et al 2005). Interpretation of such data requires care, as the presentation of prostate cancer could be altered or delayed in patients with lower testosterone levels.
Testosterone is an important hormone for both men and women. Even though it’s often associated with a man’s libido, testosterone occurs in both sexes from birth. In females, it plays a part in sexual drive, energy, and physical strength. In males, it stimulates the beginning of sexual development and helps maintain a man’s health throughout his life.
As already indicated previously, testosterone levels, particularly bioavailable testosterone, fall with advancing age. This decline in testosterone availability may start to occur early in the forth decade but it usually becomes clinically manifest in the 50s and 60s. Although there is continuing debate about the best way to diagnose hypogonadism in the aging male, there appears to be a general consensus that symptomatic men with reduced levels of testosterone should be given a trial of testosterone therapy if there is no contraindication to do so (Bain et al 2007).
While it would be nice to buy a testosterone pill from the local supplement store and have your testosterone levels go up, such a magic pill does not exist. As you can see from the above rundown, while a few supplements may be somewhat effective if your T levels are already low, none will significantly raise your testosterone above a baseline level. Thus, the basics of keeping your T levels high remain pretty simple:
Zinc is involved in virtually every aspect of male reproduction, including testosterone metabolism. Several studies support the use of zinc for treating low sperm counts, especially when accompanied by low testosterone levels. In these studies, zinc has shown an ability to raise both sperm counts and testosterone levels. Many men may be suffering from low testosterone simply because of a zinc deficiency. Taking 30–45 mg of zinc per day is recommended; balance with 2–3 mg of copper for best results.
Dobs and colleagues found that men with an increased body mass index had both reduced testosterone and reduced high density lipoprotein (HDL) levels. Treatment with testosterone increased the levels of HDL (Dobs et al 2001). Rising levels of HDL are not a consistent finding with TRT. More often, however, one finds reduced total cholesterol, low density lipoprotein (LDL) cholesterol and triglyceride levels with TRT (Zgliczynski et al 1996; Whitsel et al 2001).

The most common "out of balance" testosterone levels are found to be on the low side of normal; this occurs because a male's highest testosterone level usually peaks at about age 20, and then it decreases slowly with age. It has been suggested that a 1% decrease in testosterone level per year is not unusual for middle-aged (30 to 50 years old) and older males. While this decrease may not be noticeable in some men, others may experience significant changes starting in their middle-aged years or more commonly at age 60 and above. This drop in testosterone levels is sometimes termed hypogonadism, "male menopause" or andropause.
"A lot of the symptoms are mirrored by other medical problems," Hedges says. "And for a long time, we were not attributing them to low testosterone, but to diabetes, depression, high blood pressure, and coronary artery disease. But awareness and appreciation of low testosterone has risen. We recognize now that low testosterone may be at the root of problems."
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