By far the most common side effect to GH therapy is joint pain or joint swelling. Joint pain presents 27% of the time, and joint swelling will present 41% of the time.
These joint issues are related to incorrect dosages, and your doctor will adjust the dose should these side effects occur. Correct dosage alteration will cause these side effects to disappear.
A very small percentage of people may develop antibodies to the protein. This will occur with any protein therapy treatment.
GH treatment can cause high levels of the protein IGF-I. 35% of child onset patients treated for two years with GH, developed an elevated IGF-I protein count at some time in the course of treatment. The long term effects of this elevated IGF-I count are not yet known. Should a patient present higher than normal levels of IGF-I, the dosage will be altered in an effort to normalize IGF-I levels.