Lactic acid comes from milk. It is also called alpha hydroxy acid and is used for skin rejuvenation or for acne prone skin. Urea helps to break down dead skin cells, loosen scaly skin and promote healing. Salicylic acid slows the shedding of skin cells to prevent the pores from clogging. All of these ingredients are used in a variety of skin creams for acne, anti-aging and moisturisers.
A variety of over-the-counter acne creams contain lactic acid and salicylic acid, according to the Mayo Clinic website. Lactic acid comes from sour milk. It is used to exfoliate skin and remove dead skin cells, which help to reduce acne inflammation. Lactic acid, also referred to as alpha hydroxy acid-AHA, reduces acne scarring by removing dead skin cells and promoting cell turnover for smoother skin.
Salicylic acid slows the shedding of skin cells inside the hair follicles. This prevents clogged pores and acne breakouts. Salicylic acid may also help to break down whiteheads. Salicylic acid may cause mild skin irritation or stinging.
Lactic acid exfoliates the skin, removing dead skin cells and shows positive results in reversing some effects from sun damage, according to the American Academy of Dermatology. Lactic acid in the form of AHAs is a common ingredient in anti-ageing creams. It helps lighten the skin evening skin tone and brown spots associated with age. AHA creams cause sun sensitivity and an increased chance of sunburn. The Food and Drug Administration advises using a broad-spectrum sunblock of SPF of 30 or higher while using creams containing AHAs.
Lactic acid and urea are used in moisturising creams. Lactic acid is a humectant that absorbs water from the air and holds the moisture in the skin. It also softens scaly and thickened skin. Urea is used in moisturisers to remove dry and scaly skin and reveal new soft skin underneath. It is a debriding agent, which softens dead or devitalised skin tissue and removes the surface layer. It is a common ingredient in face, hand and body creams. Urea cream may cause slight skin irritation, burning, stinging or itching.