For most people, oily skin is experienced during the teen years. However for some people, this problem can persist long after puberty ends. Oily skin is a common skin condition that occurs when the sebaceous glands become overactive and produce excess oil in the skin. This often causes the skin to appear shiny or greasy, and pores to appear open and large. Oily skin can disrupt the skin’s natural shedding process, which can lead to an accumulation of dead skin cells. Dead skin cells can clog and block the pores, leading to acne and blemishes. However, one benefit of oily skin is that it may be less wrinkled as it ages, in comparison with other skin types. Sebum produced by the sebaceous glands acts as a lubricant and also helps retain moisture in the epidermis. Oily skin may be caused by a variety of factors including heredity, diet, pregnancy or weather. An increase in testosterone levels during puberty is one of the main causes of oily skin for teenagers. In the majority of cases, oily skin can be easily managed with proper skin care.