Most of us have become familiar with AHAs (alphahydroxy acids) and BHAs (betahydroxy acids), but PHAs are fairly new to many. PHA, which stands for polyhydroxy acids, is the more gentle group of hydroxy acids which in clinical trials showed exceptional skin benefits with less irritation than other AHAs.
AHAs are known and proven for their ability influence skin cell turnover rate and regulate skin formation with the most tangible result being peeling. PHA quite simply is an AHA, but slightly larger in size with more hydroxy groups. Poly = multiple, hence the name polyhydroxy acids.
Some examples of PHAs are sugar acids such as lactobionic acid which comes from oxidized lactose (milk sugar) and gluconolacctone which comes from oxidized glucose (natural sugar in the human body).
Both PHAs and AHAs have similar anti-aging benefits, with the difference primarily being the irritation caused to skin. With AHAs containing only one hydroxyl group, they are known to cause burning, stinging and tingling. It is thought that the larger molecular size of PHAs penetrates at a slower rate than AHAs and hence causes less irritation.
PHAs is the ideal hydroxy acid for those with sensitive skin that can’t tolerate AHAs or those who are looking for gentler alternatives to AHAs.
The benefits of PHAs like with AHAs, include enhancing cell turnover, improving skin tone, reduction in the appearance of wrinkles and fine lines, hydration and general skin smoothness. Another great benefit of PHAs is that they chelate excess iron in the skin, thus reducing oxidative damage.
Chelation is the process where metal is trapped so it can be rendered inactive and not be able to cause free radical damage induced by iron. For example in iron overdoses chelation therapy is used so the body can trap and remove the excess iron in the body. Iron is one of the inducers of pigmentation in photo aged skin.
Overall, if you are thinking of starting AHAs, or switching to something more gentle, then a PHA product is the way to go.