Blood-Sugar Spikes Send Testosterone Levels Down

Post-meal surges in blood sugar can cut a man's level of circulating testosterone by about a quarter, new research shows. The finding might help doctors decide to test for testosterone levels while patients are fasting, the researchers said.

The study, slated for presentation Saturday at The Endocrine Society's annual meeting in Washington, D.C., involved 74 men, including 42 with normal blood sugar, 23 with impaired blood sugar levels ("pre-diabetes" ) and nine newly diagnosed with type 2 diabetes. Each of the men drank a sugary solution (75 grams of pure glucose), which typically triggers a spike in blood sugar levels. They then had their testosterone levels tested.

The researchers found that, regardless of whether the men had diabetes or not, blood levels of testosterone dropped by as much as 25 percent after they drank the sugary drink. This trend continued for more than two hours after the glucose was ingested. In fact, 15 percent of the 66 men with normal testosterone levels before the test had low testosterone ("hypogonadism" ) at some point during the test...more