Taking testosterone undecanoate capsules will not work within a few minutes, and it will take at least about 5-7 days to have the corresponding effect. Testosterone undecanoate is mainly used to promote androgen secretion, which can be clinically applied to primary or secondary male hypogonadism, decreased libido, mental depression and weakness, etc. It can also better maintain male sexual function gender characteristics. In addition, it can also be used in the treatment of rheumatoid arthritis adjuvant, breast cancer metastasis, and androgen deficiency syndrome. However, testosterone undecanoate should not be used in children, otherwise it will lead to precocious puberty and early epiphyseal closure, thus affecting the growth and development of children. Since testosterone undecanoate is not a quick-acting drug, it will not have immediate effect after taking it, and it usually takes about 5-7 days for improvement; meanwhile, patients should monitor liver and kidney functions and pay attention to the appearance of adverse reactions while taking it. In conclusion, patients are advised to take the medication according to their condition under the guidance of clinicians, pay attention to rest and avoid straining.