Pore-refining cleansers typically contain chemical exfoliants that help reduce the appearance of pores. Cleansers containing salicylic, lactic or glycolic acid encourage skin cell turnover, causing skin to release dead skin cells before they end up in the pores. In addition, these ingredients control excess sebum, or oil, production in the skin. Excess oil is a major cause of enlarged pores.
A pore is essentially an opening of a single hair follicle in the skin. Each pore contains a hair and a sebaceous gland, which secretes sebum. When the sebaceous gland produces too much oil, the pore can become clogged, forming a pimple, or stretched and misshapen over time.
Pore size is determined by genetics, skin type and age. Those with oilier skin types are more likely to experience enlarged pores due to excess oil production. Middle-aged people see enlarged pores as a result of aging skin, which takes longer to shed old cells and regenerate as quickly. The texture of the skin becomes more coarse and pores appear wider as skin loses its youthful elasticity.
Pore-refining products such as cleansers cannot eliminate pores and do not provide permanent pore tightening. They must be used consistently to keep pores looking clear and tight.