In recent years, attention has been focused on the role of INSL3 and its receptor RXFP2 in bone metabolism in clinical disorders such as hypogonadism and Klinefelter syndrome, where a reduction or absence of INSL3 is often accompanied by bone loss. In addition, INSL3 has been associated with postmenopausal osteoporosis in women. The purpose of this review is to summarize the mechanism of action of INSL3 in regulating bone formation by comparing the differences between INSL3 and sex hormones. We discuss the role of INSL3 in bone metabolism, especially its effects on osteoblasts and bone-associated proteins. Due to the many side effects of testosterone replacement therapy, we propose the use of INSL3 receptor agonist as a potential treatment to improve osteoporosis.