Negative Side Effects While Using HGH Swelling HGH must be injected and is available by prescription only. HGH injections may cause swelling of the hands, feet, arms or legs. This swelling may go away during treatment or with reduction in dosage or usage. Muscle & Joint Pain Another side of effect of HGH use is musculoskeletal discomfort with muscle or joint pain and aches or stiffness in the hands and feet. This side effect may only occur during treatment and resolve after discontinuing use of HGH. Carpal tunnel syndrome is another possible side effect. This affects the median nerve that runs from the forearm to the hand and can cause weakness, pain or numbness in the hands and wrists, according to the National Institute of Neurological Disorders and Stroke. Breast Enlargement HGH may cause enlargement of the breasts in some men. A study by L. Cohn, et al., published in the October 1993 issue of “Clinical Endocrinology,” examined the relationship between insulin-like g...