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 into the skin and just work on the the epidermis. They therefore rarely cause irritation and can even be used on skin with dry, itchy conditions such as rosacea and eczema.
How will adding a PHA benefit my skin?Like AHAs, PHAs exfoliate the skin 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 anti-oxidant 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 wash 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, by maybe using them every other day in order 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 times 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, toners, 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 photoaging. They’re also effective when used after aesthetic procedures such as lasers or peels to help the skin hydrate and heal.