Another common ingredient in cosmetics is various acids. Even though the word acid by itself may sound like a potential risk of burns, but it’s simply necessary for good skin condition, when used in a balanced and appropriate amount.
AHA glycolic acid. AHA (or alpha hydroxy acids) is a large family that includes many acids used in the cosmetics industry (e.g., lactic, mandalic, tartaric). The main function of these acids is to help get rid of dead skin cells and thus rejuvenate the skin. They break down the glue that connects dead cells, making it easy to remove. AHA is suited best for a dry skin. AHA glycol extracted from sugar cane is an extremely fine substance, so it penetrates quickly into the skin and works effectively. This acid can be used to treat a variety of rashes, as these are usually caused by pores clogged with dead skin cells. However, the main function of this substance is rejuvenation by removing dead skin particles. AHA glycol also helps the skin to absorb other beneficial substances better, so it can be found in frequent facial care products.
BHA (beta hydroxy acids) comparing to AHA – works stronger and deeper. If AHA are designed to remove dead skin cells from its surface, BHA penetrates the pores and cleans the dirt out of them. For the latter reason, this substance is a common choice in the treatment of acne or acne and is better suited for those with oily skin. The most commonly used acid in cosmetics is salicylic.
Source: Skin Store.
Azelaic acid can be extracted from barley, wheat, and rye, but laboratory-developed azelaic acid is commonly used in cosmetics. Like AHA and BHA, it can help get rid of dead skin cells and clear clogged pores, but is not as effective as the latter. Azelaic acid, on the other hand, is indispensable for obtaining an even skin tone: reducing blemishes, fading acne marks, rejuvenating and smoothing the skin surface.
Source: Paula‘s Choice.