"Testosterone supplements have grown into a  billion market with millions of men of a certain age taking it for low energy low libido low mood  what marketers call low T  even though thats not an approved use. Now the first study to rigorously test whether the quintessential male hormone can fight the toll of aging shows it isnt much of a youth elixir. A year of testosterone treatment was no better than a placebo for memory and thinking and it increased fatty plaque in coronary arteries a risk factor for heart disease. The hormone helped anemia and low bone density in the minority of men with those conditions which can be treated with other proven therapies. The results published Tuesday in the Journal of the American Medical Association and JAMA Internal Medicine add to findings from a year ago  http_Testosterone_gets_mixed_report_in_big__Pennled_study.htmlTestosterone did not improve fatigue or walking speed and its modest benefits on sexual function faded by the end of the study. The hopes for testosteroneled rejuvenation for older men are dimmed and disappointed if not yet finally dashed University of Sydney professor of medicine David J. Handelsman concluded in an editorial accompanying the latest results. University of Pennsylvania endocrinologist Peter Snyder who led the complicated governmentfunded clinical trials involving  senior men at  medical centers  disagreed. It shows for the first time that treatment of older men with low testosterone has certain benefits including bone density and anemia Snyder said. I would say the effects on bone and anemia were striking. He added a caveat. Even though the  million T Trials are the most conclusive studies ever done on the hormone researchers didnt follow enough men long enough to tell whether testosterone increases risks such as heart attacks stroke or prostate cancer. AbbVie which donated its leading brand Androgel to the trials said in a statement that the company is committed to our patients and is proud of our continuous support of research that advances science for the benefit of hypogonadism patients. Actually hypogonadism occurs when the body doesnt produce enough of the hormone due to disease injury or chemotherapy.  Its the condition for which testosteronereplacement therapy is approved. Prescribing testosterone for agerelated deficiency  which is only vaguely defined  took off  in .  The trend was driven not by solid scientific evidence but  by the introduction of convenient rubon testosterone products the first being Androgel. Many men are put on testosterone with no tests of their levels or despite tests showing normal levels a study of Medicare claims found. Two years ago the U.S. Food and Drug Administration cracked down http_FDA_warns_about_testosterone_for__Low_T_.html on this overprescribing. It ordered drugmakers to revise product labeling to stress the approved use and to warn that the drug may increase the risk of heart attacks and stroke. Another order  that manufacturers conduct a clinical trial to clarify the heart risks  is under discussion the FDA said Friday. Concerns about testosterone use also led the National Institute on Aging to fund the T Trials which began enrolling men over age  in . T Trials researchers had to screen more than  men to find  with confirmed abnormally low testosterone levels along with one or more agerelated symptom that the hormone might help. More than  percent of the men were also obese a condition that can depress testosterone levels. Now with a clearer scorecard on benefits Snyder would like to see the government fund a study to tease out the risks  an effort that would take  men five years of treatment and  million. Other experts see no point in defining the downsides of a therapy with weak upsides. The improvements in outcomes in the T Trials were minimal said Deborah Grady a professor of medicine at the University of California San Francisco and an editor of JAMA Internal Medicine. Grady was a leader of the Womens Health Initiative the mammoth government study http_As_testosterone_use_grows__questions_on_risks_await_answers.html that in  shattered the deeply held belief that menopausal hormone therapy protected womens hearts. The National Institutes of Health agreed to fund the initiative because estrogen unlike testosterone had decades of circumstantial evidence of cardiac benefits. Testosterones cardiac effects are still unsettled. Some studies that mine medical records  including one in Tuesdays JAMA Internal Medicine  have found men taking it have fewer heart problems. The T Trials anemia findings add to the complexity. Testosterone is known to increase production of red blood cells which carry hemoglobin a protein that ferries oxygen. In  men with mild anemia  a deficiency of red blood cells or hemoglobin that can cause fatigue  testosterone was better than a placebo at boosting hemoglobin. The hormone corrected anemia that had no apparent cause as well as anemia caused by iron deficiency or inflammation. However in six men the hormone triggered an oversupply of red blood cells. Testosterone labeling warns about this because the blood can become too thick a risk for dangerous blood clots or stroke. Like all participants in the trials the six men were closely monitored so the problem was detected their testosterone dose was reduced and their red blood cell counts returned to normal Snyder said. The results illustrate that decisions about testosterone treatment need to be individualized said Evan Hadley  director of the National Institute on Agings geriatrics division. Physician Michael Carome director of health research at the consumer advocacy organization Public Citizen drew a different bottom line This body of research indicates that testosterone is not the fountain of youth that some patients doctors and industry have hoped or represented it as being."