Most acne products you can buy over the counter will be based either on salicylic acid or benzoyl peroxide. Both of these are well proven anti-acne ingredients and are useful in managing "mild to moderate" acne during your teenage years and into your 30s. Both ingredients are absorbed by the skin into the hair follicles where they kill the specific bacteria (called P acnes) which cause inflamed, red zits after the opening of the pore has blocked. Benzoyl peroxide is used in medicines that you would get from your doctor or dermatologist (usually in combination with other active ingredients) but is also available in treatment products over the counter. Salicylic acid is more popular as an anti-acne ingredient, appearing in a wide range of products and formats such as washes, scrubs, gels, creams, pads and wipes.
Washing with non-medicated products will help keep skin free of excess oil and dead skin cells, but not deal with acne-causing bacteria. Salicylic acid and benzoyl peroxide help stimulate skin turnover which unblocks pores.
Now that we've covered that, let's bust some myths: