CT is a peptide consisting of 32 amino acid residues and is produced by thyroid C cells. Its main physiological effect is to lower blood calcium, acting through target organs such as stomach and kidney. When blood calcium is elevated, blood CT secretion increases and can act directly on the receptors on osteoclasts, inhibiting the activity and number of osteoclasts, thus inhibiting bone resorption. CT can also inhibit small intestinal calcium absorption, while high doses of CT promote small intestinal calcium absorption. It can be seen that CT plays an important role in maintaining calcium homeostasis and is one of the three main regulatory hormones of calcium metabolism, along with parathyroid hormone (PTH) and 1,25(OH)2D3. In recent years, many scholars have shown in animal and human bone histomorphology experiments that CT has a direct effect on osteoblasts in addition to inhibiting osteoclastic bone resorption, and that the effect of CT on osteoblast anabolism may be in maintaining bone formation rate, increasing cortical bone growth in rats and rabbits, and indirectly increasing cell reproduction (21). Experiments have also demonstrated that CT can increase bone mineral density (BMD), especially cancellous bone mass. Many experiments have demonstrated that: (1) CT reserve function is lower in females than in males, and RIA of extracted serum clearly shows that CT basal values are significantly higher in males than in females, suggesting that there are differences in CT secretion and reserve function by gender; (2) CT basal and response values are significantly negatively correlated with age, and RIA of serum extracted by the FPLC method shows that CT response values in young females are significantly higher than those in older females, suggesting that CT secretion and response values in young females are significantly higher than those in older females. , showed significantly higher than older women, indicating that the secretion and reserve function of CT decreases with age; (3) In postmenopausal patients with osteoporosis, the CT response to calcium was significantly lower than that of normal controls, suggesting that the reserve function of CT is reduced in postmenopausal osteoporosis. Therefore, many scholars believe that the decrease in blood CT concentration may be one of the reasons for women’s susceptibility to primary osteoporosis. In both animal experiments and clinical settings (22-25), CT has been shown to be effective in osteoporosis, especially in high turnover osteoporosis, preventing bone loss and increasing bone cortical amplitude and bone density.CT promotes the production of renal 1,25(OH)2D3 and stimulates intestinal calcium absorption. CT is particularly effective for type II osteoporosis combined with low back pain, which can be relieved by early administration, mostly within 2 weeks. However, long-term administration of CT can also cause the phenomenon of Escapa. At present, the clinical formulations are pig calcitonin, eel or salmon calcitonin and its derivatives and fully synthetic preparations, such as calcitonin (salmon CT), calcium (eel CT), but these drugs are relatively expensive, injectable medication is very inconvenient, side effects skin itching, injection local pain, transient nausea and vomiting, facial flushing with heat, so long-term application is very difficult, in recent years, calcitonin has been synthesized In recent years, the diclofenac has been synthesized as a nasal spray, but there is still no oral agent.