ALPHA HYDROXY ACIDS (AHAS)

Alpha hydroxy acids (AHAs) are a group of plant- and animal-derived acids used widely in skincare as chemical exfoliants. 
These water-soluble acids work by dissolving the "glue" that binds dead skin cells together on the surface of the skin. 
By breaking these bonds, Alpha hydroxy acids (AHAs) encourage dead cells to shed effortlessly, clearing the way for new, brighter, and more evenly pigmented skin cells to generate.

Alpha hydroxy acids (AHAs) represents an entire category of compounds rather than a single chemical, there is no single CAS number for AHAs as a whole.

Glycolic Acid: 79-14-1
Lactic Acid: 50-21-5 (General / DL-mix), 79-33-4 (L-lactic acid), 10326-41-7 (D-lactic acid)
Mandelic Acid: 90-64-2 (General / DL-mix), 611-71-2 (R-enantiomer), 17199-29-0 (S-enantiomer)
Citric Acid: 77-92-9 (Anhydrous), 5949-29-1 (Monohydrate)
Malic Acid: 6915-15-7 (General / DL-mix), 97-67-6 (L-malic acid)
Tartaric Acid: 87-69-4 (L-tartaric acid), 133-37-9 (DL-mix)

“Alpha hydroxy acids (AHAs) are a group of plant and animal-derived acids used in a range of skincare products,” says Claire Williams, skin expert and founder of the WOW Facial.
The water-soluble chemical exfoliants can be either naturally occurring or synthetic and many are derived from organic sugars – glycolic acid is from sugar cane, lactic acid is from milk, malic acid is derived from apples and mandelic acid is from almonds.
Alpha hydroxy acids (AHAs) means alpha hydroxy acid. AHAs, along with BHAs (beta hydroxy acids), are two of the main types of hydroxy acids – a type of non-organic acid – used in beauty and skincare. 
Also known as fruit acids, they have been used as an ingredient in products to help improve the appearance and hydration of skin for decades.

Alpha hydroxy acids (AHAs) works as a chemical exfoliant, helping to remove dead cells from the top layer of the skin. This can help to smooth fine lines, improve skin texture, and decrease blemishes. 
Clinical trials have shown that Alpha hydroxy acids (AHAs) are effective in reversing the effects of photoaging and improving the appearance of fine lines and wrinkles, skin elasticity, tone, and hydration. 
As such, Alpha hydroxy acids (AHAs) are widely used for their anti-ageing benefits, reducing the appearance of dark spots, and for their benefits for spot and acne-prone skin

What are the benefits of using Alpha hydroxy acids (AHAs)?
“Alpha hydroxy acids (AHAs) have been used in skincare products for quite some time, and their use has only increased with the wealth in research surrounding their benefits for skin,” says Claire.
Glycolic and lactic acids tend to be the most commonly used Alpha hydroxy acids (AHAs) in cosmetic products. 
Their main benefits include helping to reduce visible sun damage, smoothing the appearance of fine lines and encouraging hydration.
"But they can also help get rid of layers of dead skin cells, promote radiance, reduce dry skin and smooth," says Claire.
Essentially: they help skin peel away the surface so that new, softer and more evenly pigmented skin cells may generate and take their place.