Testopel is a tiny pellet that contains testosterone. The pellet is inserted into the fatty layer of tissue just beneath the skin. Once there, the pellet slowly dissolves, releasing testosterone into the body for three to four months (or sometimes as long as six months).As a result, testosterone blood levels increase.he pellet is inserted into the fatty layer of tissue just beneath the skin. Once there, the pellet slowly dissolves, releasing testosterone into the body for three to four months (or sometimes as long as six months).