Testosterone supplements don't do older men much good, Dutch researchers said on Tuesday.
The amount of the hormone in the blood drops naturally as men age and is associated with a decline in physical strength and mental functioning as well as a fatter midsection.
In a study of 230 men aged 60 to 80, those taking testosterone pills in a relatively small dose for six months developed slightly more muscle mass and less fat compared to those not taking the hormone. But the 80-milligram supplements did not provide a boost to overall health or quality of life.
The testosterone supplementation did not have a net health benefit, wrote study author Dr. Marielle Emmelot-Vonk of University Medical Center Utrecht, the Netherlands.
To maintain good health in old age, "it is important that you eat healthy food, and it's important that you do a lot of activity," Emmelot-Vonk said in a statement.
Those taking supplements were no stronger and they did not exhibit greater mobility than those taking an inactive placebo. The hormone did not boost their bone density or mental functioning either, the study found.
The men taking testosterone did improve their insulin sensitivity, but they also had lower levels of "good" cholesterol compared to men taking a placebo. Losing sensitivity to insulin is a factor in adult-onset diabetes, while good cholesterol plays a role in staving off heart disease.
The participants were chosen because they had slightly lower-than-average testosterone levels before the study began.
At the end of the study, nearly half of those taking testosterone exhibited the collection of symptoms known as metabolic syndrome — a fat midsection and other conditions that can lead to heart disease and diabetes. However the difference in metabolic syndrome rates between testosterone takers and placebo takers was not considered statistically significant.
Emmelot-Vonk said the study, which was published in the Journal of the American Medical Association, was the largest so far on the impact of testosterone supplements.