Xiao Liang went to the hospital for a checkup because of his small size. The doctor diagnosed him with “growth hormone deficiency” and gave him a kind of injection called growth hormone. When Xiao Liang’s mother heard the word “hormone”, her heart got fuzzy. Can the hormone be used? What kind of medicine is growth hormone and will it cause obesity? Human growth hormone is neither a drug nor a medicine, because normal people can secrete growth hormone by themselves from the anterior pituitary gland at the base of the brain. This growth hormone is distinctly race-specific, and only human growth hormone works on human growth; animal growth hormone does not work on humans. Human growth hormone (hGH) is a protein with a long chain of amino acids (191 amino acids). hGH has what role? It is indispensable for human growth, and if it is missing, people are short, formerly known as pituitary dwarf, or growth hormone deficiency. hGH promotes the formation of articular cartilage and the growth of epiphyseal cartilage. Research suggests that its action is mediated by a mediator, insulin-like growth factor (IGF-1). hGH has many other complex effects, such as promoting protein synthesis and accelerating lipolysis and utilization (and therefore not causing obesity). hGH is secreted in bursts of waves, and is difficult to measure in the blood when secretion is low. Secretion increases with hunger, exercise and deep sleep. It is also regulated by a number of hormones secreted by the hypothalamus. How is human growth hormone produced as a drug? In the past, it was extracted from the pituitary gland of human cadavers. Because the amount of hGH contained in each pituitary gland was limited, the hGH extracted from 1000 pituitary glands of cadavers could only treat one pituitary dwarf patient, so the supply of this drug far exceeded the demand, and China could not produce it at that time. Moreover, there were side effects after use. Fortunately, with the development of science and technology, it is now possible to produce hGH by genetic engineering recombinant technology, and many countries, including China, can produce this new type of hGH. The hGH produced by this method has exactly the same structure and high purity as the hGH in human body. Due to the abundant drug source, not only pituitary dwarf patients can be treated, but also some dwarfism caused by other reasons. Genetically engineered recombinant growth hormone has fewer side effects, but it has been reported in the literature that a few people may suffer from hypothyroidism, abnormal glucose tolerance, transient benign intracranial pressure increase, increased dark pigmented nevi and allergic rash after applying growth hormone. There are two other disadvantages: 1) it is more expensive, and 2) it currently requires daily injection before bedtime, which is more painful for children. For the second disadvantage, there is now a method to deal with it. Polyethylene glycol recombinant human growth hormone will be marketed soon, and its active ingredient source: a covalent coupling composed of recombinant human growth hormone (rhGH) and branch-type polyethylene glycol (PEG), which can be injected subcutaneously once a week, reducing the pain of frequent injections for children. Therefore, the application of rhGH requires mastering the indications and using it under the guidance of a specialist. It should be used with caution in children with diabetes in the family and is contraindicated in oncology patients.