Alpha Hydroxy Acids (AHAs) for your skin: what are they and what do they do?

Are you on a quest for smoother, more even-toned and younger-looking skin? Then you may already be familiar with Alpha Hydroxy Acids (AHAs) or even the most famous AHA – glycolic acid. But what exactly are AHAs? How do they differ and which one is best for your skin? Read on to discover everything you need to know about AHAs.

What is Alpha Hydroxy Acid?

Alpha Hydroxy Acids are a group of natural and synthetic ingredients that are used to exfoliate the top layer of your skin. Exfoliation is simply the removal of dead skin cells from the surface of your skin. After exfoliating with an AHA exfoliant your skin will feel fresher, softer and more hydrated, and with long term use it will become firmer too. That’s why anyone seeking younger-looking skin should add a product with Alpha Hydroxy Acid to their skincare routine.

AHAs occur naturally in many common foods, but most skincare products use a synthetic form, as these are easier to stabilise and more consistent in quality and efficiency.

Glycolic acid

Glycolic acid occurs naturally in sugar cane and has the best track record of all the Alpha Hydroxy Acids. It is the most researched AHA and studies show that glycolic acid, together with lactic acid, demonstrates the most impressive results for all ages and skin types.

Glycolic acid is special because of its small molecule size which enables it to easily penetrate through the top layers of skin and reveal healthier-looking skin. Glycolic acid also has the ability to hydrate skin and to ‘teach’ skin to retain its natural moisture. When used in concentrations of 5% and upwards, glycolic acid can also improve firmness and resilience while lessening other signs of sun damage.

Find out more about Paula’s Choice AHA exfoliants with glycolic acid.

Lactic acid

Lactic acid can be derived from milk and works more or less the same as glycolic acid. But it acts more slowly because its molecular size is slightly bigger, reducing its ability to penetrate the skin’s top layers. Lactic acid at a 2% concentration hydrates skin, from 5% upwards it starts to work as an exfoliant - a 5% to 10% concentration would be best for a skincare product with exfoliation as its main goal.

Malic acid

This AHA occurs naturally in apples. The molecules of malic acid are bigger than those of glycolic and lactic acids, but are still able to exfoliate skin and benefit from antioxidant properties. Malic acid at a concentration of 1% to 2% is sometimes added to AHA exfoliants containing glycolic acid and lactic acid, enabling exfoliation in different layers of skin.

Tartaric acid

Tartaric acid appears in grapes (and hence red wine). The molecules of tartaric acid are slightly larger than malic acid and twice as big as glycolic acid.

Tartaric acid can function as an exfoliant when used at the same concentrations as glycolic acid or lactic acid and can enable exfoliation in different layers of skin. But tartaric acid is mostly used to help other exfoliants stick to the right pH range. This is essential to optimise an exfoliant’s effectiveness.

Resist Anti-Aging Advanced Smoothing Treatment 10% AHA consists of a combination of the 4 above mentioned Alpha Hydroxy Acids, enabling this treatment to exfoliate different layers of skin.

Citric acid

Citric acid is found in a variety of different citrus fruits. In concentrations of 10% and higher it can work as an exfoliant, but it is seen to be more irritating as it has a low pH of 2.2.

In a lot of skincare products, you will find citric acids used in small proportions as an antioxidant. They are also used to adjust pH levels, ensuring formulas keep to a pH level which is efficient and gentle on skin.

Some AHA products claim that they contain citric acids that work as natural exfoliants. That’s all very well, but there is no research proving that these kind of extracts are able to exfoliate skin.

Mandelic acid

This AHA is not used as often as the other AHAs because there is less research to prove its effectiveness. But mandelic acid shouldn’t be underestimated. As the AHA with the largest molecules, it is able penetrate the skin more slowly - good news for people with sensitive skin.

Research has shown that mandelic acid can stimulate skin to produce more oil, which is not ideal for people with oily or combination skin, but could be beneficial for those with dry skin.

Research on using mandelic acid as a peel involved concentrations of 20% to 40%. But concentrations for regular skincare are still unknown.

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