Acne typically begins with sebaceous glands in the hair follicles producing too much oil. This leads to oily skin, which prevents dead skin cells from shedding from the surface. These cells build up and block pores, creating an advantageous environment for anaerobic bacteria that cause acne. Pore blockages also may become inflamed and swollen. Natural acids and the synthetic products derived from them are useful for treating acne, as explained by the U.S. Food and Drug Administration.

Alpha-Hydroxy Acids

Alpha-hydroxy acids are exfoliants, meaning they help to slough away the top layer of skin, allowing oxygen to penetrate pores and kill bacteria. Glycolic acid, for instance, is a very common ingredient in skin care products and also is used in chemical facial peels. This AHA is mainly derived from sugar cane when used for skin care, according to the FDA. A glycolic acid peel is a non-invasive light chemical peel that removes the upper layers of damaged and dead skin cells and promotes new healthy cells, as explained by CosmeticLaserMD. Another alpha hydroxy acid included in topical acne remedies is lactic acid, derived from milk.

Salicylic Acid

Salicylic acid, a type of beta hydroxy acid, is found in plant sources such as birch and willow bark. This acid is useful for treating skin disorders, and the substance is included in many topical acne remedies. Salicylic acid softens keratin, a protein that is part of cells in the upper layer of skin, as explained by DermNetNZ. This helps to loosen dry scaly skin, so these cells can be sloughed away. Salicylic acid also helps to break down whiteheads and blackheads.

Azelaic Acid

Azelaic acid is produced by a yeast that lives on normal skin, as noted by DermNetNZ. Another acid useful as an acne remedy, azelaic acid, decreases growth of bacteria in the pores, softens keratin and reduces inflammation. Azelaic acid also decreases skin pigmentation. This makes it especially beneficial for patients with darker skin whose acne leaves brown spots, and for people with melasma, skin discoloration due to sun exposure.