You’ve probably heard of skin acids such as alpha hydroxy acids (AHAs) and may well be using them in your skincare regime, but there’s now an acid appearing in products from high-end to high-street that is gentle enough to be used on the most sensitive of skins, and has got the beauty world all aflutter.

What are PHAs?

PHAs or polyhydroxy acids fall under the AHA family, but unlike AHAs they work on the outer layers of the skin (the epidermis).

Overdo powerful AHA products and the skin can end up red, raw, and stinging, while those with the most sensitive skins are likely not to be able to tolerate them at all.

However the good news is that PHAs, due to their larger molecular structure, do not penetrate as deeply and just work on the the epidermis.  Therefore they rarely cause irritation and can even be used on skin with dry, itchy conditions such as rosacea and eczema.  

How will a PHA benefit my skin?

Like AHAs, PHAs exfoliate by dissolving the protein bonds that stick or glue dead skin to the surface of the face. This helps to speed up cellular turnover, minimising fine lines and wrinkles and brightening and smoothing the complexion.

PHAs are humectants, meaning they have the ability to attract moisture to the skin, so will help keep skin moist and hydrated.

With both anti-inflammatory and antioxidant properties, PHAs can help normalise the skin and stimulate skin repair. This strengthens the skin barrier function making the skin stronger and more resilient.

PHAs help to fight glycation, which is a process that takes place when digested sugar permanently attaches to the collagen and elastin in the skin, damaging and weakening it in the process.

Are PHAs safe? Are there any downsides?

Luckily PHAS aren’t known for having side effects. They don’t go deep enough into the skin, but gently sweep away any debris that’s sitting on top of it.

However, very sensitive skins are best to use them carefully and do a patch test first. As with any new product it’s worth starting out slowly, maybe by using them every other day to see how the skin reacts.

How should they be used?

Fortunately PHAs are found in lots of products, the most common ones being gluconolactone, galactose and lactobionic, and they all do the same thing.

In order to get the maximum benefit from them they are best when used in products that are left on the skin for extended periods of time, so that they have sufficient time to loosen the bonds between the cells. They can be found in all types of products from liquid exfoliators and toners, to masks and moisturisers.

Another benefit of PHAs is that they combine well with other ingredients to give additional benefits – for example, PHAs can be combined with retinoids for acne or photoageing. They’re also effective when used after aesthetic procedures such as lasers or peels to help the skin hydrate and heal.