Organic compounds that, together with AHAs, retinoic acid (vitamin A), and ascorbic acid (vitamin C) belong to the class of so called carboxylic acids. There are different types of PHAs and they occur in nature. Some of them (for example, glyconic acid) can be found in our skin, and are a major component of synthesis of skin’s natural moisturizing factors (such as hyaluronic acid).
PHAs are typically are water-soluble, which means that the products that contain them are more likely to have a watery rather than oily texture.
In skincare, bionic acids (for example, lactobionic and maltobionic acids) are often mentioned as PHAs, even though technically they are in their own group.
In terms of skin goals, PHAs can help with:
PHAs are considered to be more gentle to the skin and might cause less irritation compared to AHAs. There is no conclusive evidence for this yet though.