Blog — testosterone

Men and testosterone therapy have been a hot topic in the news recently. Stories are filled with cautions about the use of testosterone therapy in men causing heart attacks and leading many doctors to question testosterone supplementation. A closer look at the study may provide more insight. The study released is referenced at the end of this post. (1) This study looked at 55,593 men who started testosterone therapy. Some were over the age of 65 and a smaller number were under 65. There are two important subgroups - those with cardiovascular disease and those without. The study also looked...

BY Dr. Allison Smith ZRT Laboratory SHBG, or Sex Hormone Binding Globulin, controls testosterone effect in both men and women by modulating changes in sex steroid levels. When SHBG goes up, free testosterone goes down. I like to think of SHBG as a sponge that soaks up androgens and to some degree estrogens as well. Since it binds so specifically and tightly to testosterone, it makes up part of the equation that equals androgen excess or androgen deficiency. Knowing how to manipulate SHBG can be a useful tool in a number of scenarios. Role: Bind to and carry testosterone (and less strongly...

By Dr Allison Smith, ZRT Laboratory The testicles of a man in his 20s are known to contribute about 5-10mg of testosterone per 24-hour day and levels of total testosterone in the venous blood with that amount are observed to yield roughly 300-1200 ng/dL in the morning at the diurnal peak. Testosterone, whether endogenous or given exogenously, negatively feeds back on the hypothalamus, limiting GnRH and thus LH and FSH from the pituitary. A man taking supraphysiological doses of testosterone can expect to have very low or undetectable levels of LH and FSH in the serum. What happens when the...

Posted by Dr. Kate Placzek, ZRT Laboratory. Testosterone, so meaningful to a man’s behavior, is the evolutionary force behind everything intrinsically “male.”   Historical stereotypes peg testosterone as the macho elixir of legendary magnitude – the “chest-thumping hormone of aggression.” New research, however, is beginning to tease out previously unknown subtleties of testosterone’s effects on behavior. Testosterone is non-trivial for social functioning –  increasing levels enhance generosity [1], cooperation [2], and honesty [3], thereby emphasizing that its effects in shaping male psychological makeup are infinitely more complex than previously thought. New Study Points to Altered Consumer Preferences after Testosterone Dosing...

One of the primary objectives of the Women's Health Initiative was to see if postmenopausal hormone replacement therapy (HRT) improved long-term risk of coronary heart disease, among other chronic diseases. However, the combined estrogen/progestin (Prempro) arm was halted in 2002, citing that the participants’ risk of cardiovascular disease outweighed any potential benefit of HRT in the prevention of colorectal cancer and bone fracture [1]. The conjugated equine estrogen (CEE)-only arm was also halted in 2004 citing no improvement in heart disease risk but an increased incidence of stroke, and no benefit in terms of fractures, although there was a reduced breast...