There is no such thing as how long to take Testosterone Undecanoate, it usually needs to be taken for 2 to 3 weeks first, the exact duration of the medication varies from person to person. Testosterone undecanoate is a derivative of testosterone, generally for primary or secondary hypogonadotropic replacement therapy, can improve the symptoms of decreased libido, decreased brain and physical strength, also has the role of promoting male growth, the development of the second fingerprints, regulate immune function, inhibit estrogen secretion. In general, the dosage should be adjusted appropriately according to each patient’s response to drug therapy or as prescribed by the doctor. The starting dose is usually taken for 2-3 weeks, followed by a maintenance dose. Specifically depends on the patient’s response to the drug, under the guidance of the doctor to take, not to increase the dosage or stop the drug, to avoid adverse effects on health. Underage males taking it may experience symptoms such as precocious puberty and frequent erections; adult males taking it may affect sperm quality and may also experience nausea and diarrhea after taking it. The drug is contraindicated in men who have been diagnosed or suspected of prostate or breast cancer; those who are allergic to any of the ingredients in the product; pregnant women and other people. The drug should be taken under the guidance of a doctor to avoid unauthorized use and damage to the body.