Common side effects reported with 25 mg of ibutamoren taken by mouth daily include increased blood sugar (+5–10%), decreased insulin sensitivity, and increased appetite. Other reported side effects include muscle pain and mild swelling of lower extremities, which usually diminish with regular intake of ibutamoren.[1][2][3] Additionally, there were some reports of transient elevations in liver enzymes ALT and AST.[3]
There were rare reports of hypertension and episodes of moderate heart failure in adults over 80 taking ibutamoren.[2] These safety issues resulted in the termination of clinical research with ibutamoren in older adults.