no its not a steroid,its a herb gokhru-its a spinous herb and the extract tribulus is used by people who exercise , it increases muscle endurance by decreasing oxidative stress in muscle and increases exercise capacity and is slight diuretic .so it can make you slightly leaner;but take it in the morning post workout.it is not shown to increase testosterone levels but it increases libido as it is a mitochondial enzyme enhancer which supplies the body with energy.