Biochemical workup revealed that in addition to hyperprolactinemia (7,237 [normal: 85–323 mIU/L), he had acromegaly, evident by elevated insulin-like growth factor 1 (IGF-1) level (450 [normal: 88–210 μg/L]), and a positive growth hormone suppression test, secondary hypothyroidism, and secondary hypogonadism. Here, IGF1 is linked to acromegaly.