Cernos Depot (Test Undecanoate) by Sun Pharmaceuticals is an injectable steroid, its active substance is Testosterone Undecanoate . Testosterone undecanoate is a long acting formulation of testosterone which is indicated in the treatment of individuals who have absent or very low levels of the hormone. Testosterone undecanoate is used to treat conditions in made where there is a failure of testosterone to be secreted like: primary failure of the testes to make the hormone, failure of the pituitary to release Gonadotropins. The oily suspension is injected only into the muscles. Cernos Depot (Test Undecanoate) can be injected into the buttock area once every 7-12 days. The majority of the testosterone undecanoate is bound to protein and only 2% is free. The injection is supposed to be taken once a week, but there are some body builders who do inject it every other day. This is not recommended and can lead to the formation of abscess, sores and skin infections. The injection site needs to be rotated if the injections are to be continued for a long time. The oily suspension should not be injected into the arms or the abdomen. Many body builders tend to inject the higher amount of the drug - 200mg-400mg/week. Cernos Depot (Test Undecanoate) is then slowly absorbed into the blood stream over the next few days. There are some individuals who should avoid testosterone like steroids because it can worsen the clinical condition. These conditions include: nausea, vomiting, abdominal cramps, diarrhea, swelling, increased /decreased libido, headaches, acne, oily skin, mental change including anger, depression, insomnia, diaphoresis, loss of hair, gynecomastia When taken by females, Cernos Depot definitely can cause virilizing effects like: deepening of voice, hoarseness, excess hair growth, enlarged clitoris, irregular menstrual cycles. Cernos Depot (Test Undecanoate) is converted into estrogen in the fatty tissues. The estrogen than leads to development of breast enlargement and water retention. This effect is typically seen after the steroid has been used for more than 4 weeks. The gynecomastia does reverse when the steroid is discontinued.