Rates of Erythrocytosis in Trans Males Consistent with Cis Males New research found that the greatest increases in hematocrit occurred during the first year of treatment but levels continue to increase over time until around the 20 year mark With Milou Madsen MD and Alex Pastuszak MD In the decade between 2001 and 2011, the number of prescriptions for testosterone for men over 40 tripled. It quadrupled for those 18-45. These sharp increases in men starting hormone therapy after reporting symptoms of hypogonadism has led some to speculate on the side effects of testosterone therapy, including erythrocytosis. This increase in the red blood cell population can result in symptoms that can be health or life-threatening, including obstructive sleep apnea, kidney stones, stroke, deep vein thrombosis or heart attack.