If you’re particularly into skincare, you likely already know and love exfoliating acids. Just as we’ve finally figured out the difference between alpha-hydroxy acids and beta-hydroxy acids, a new breed of acid is on the rise: poly-hydroxy acids (PHAs). You may be asking yourself what are they, and how do they differ from their alpha- and beta- counterparts? We’ll cover all of that below, but to make a long story short, PHAs might be your saving grace if you’ve found that your skin is sensitive to other exfoliating acids.
What are PHAs?
Poly-hydroxy acids (PHAs) are chemical exfoliants that are considered to be the ‘cousins’ of alpha-hydroxy. They fall under the AHA family but have much larger molecules, making them gentler on the skin. Essentially, their benefits are the same as AHAs, but they are more accommodating to sensitive skin. Common examples of PHAs are lactobionic acid and gluconolactone.
- Non-irritating exfoliant: PHAs are a great alternative if AHAs are too harsh for your skin. PHAs offer the same exfoliating benefits as AHAs but are less likely to cause any stinging or irritation.
- Gentle on the skin: PHAs are a lot gentler on the skin due to their larger molecule size. This means that the molecules take longer to penetrate the skin and won’t travel quite as deep as AHAs and BHAs do, meaning there is a lesser chance of irritation.
- Hydration: PHAs are humectants (meaning they are able to attract and retain moisture in the skin) to keep the skin hydrated.
- Anti-inflammatory and antioxidant properties: While PHAs are best known for being great exfoliants, they also contain tons of anti-inflammatory and antioxidant properties. These properties are great for fighting bacteria, redness, and protecting the skin from environmental stressors.
How PHAs differ from other acids
The difference between PHAs and the other exfoliating acids lies within their molecular structure. With larger molecules, PHAs cannot penetrate as deeply as AHAs and BHAs; they work exclusively on the surface of the skin without disturbing the deeper delicate layers. Ultimately, they offer less irritation than their acidic counterparts and are great for sensitive skin.
Best for sensitive skin
With their unique properties – their larger molecules and surface-level penetration – PHAs are ideal for virtually all skin types, particularly those who are sensitive to AHAs or BHAs. PHAs are wonderful alternatives to those with very sensitive skin who cannot tolerate many chemical exfoliants. They are also great for those with dry skin as they attract moisture and hydrate the skin. Since PHAs are a gentler acid, making them suitable for those dealing with dry, itchy skin (including those with eczema and rosacea).
How to Incorporate PHAs into your routine
- Best used in leave-on products
PHAs are most effective when used in products that are left on the skin and not washed off. Their larger molecules take longer to penetrate the skin, so having an extended period of time gives PHAs sufficient time to loosen the bonds between the dead skin cells. It is therefore recommended that PHAs are used in the form of a liquid exfoliant, toner, serum or moisturiser.
- Can be combined with other acid exfoliants
PHAs are often added to other blends of AHA- and/or BHA-based products. They act as an extra set of hands in cleaning up any surface-level debris that the other acids may have missed. Check out The Beginner’s Guide to Exfoliating Acids for more info on how to combine the different acids.
- Added in non-exfoliating products
Not only are PHAs often added to other acid-based products, but they can also be combined with non-exfoliating products to act as an extra exfoliating factor. This is so that the dead skin cells are washed away to improve the product’s penetration, leading to improved results.
This is a gentle gel that exfoliates and hydrates the skin. The active ingredients are lactobionic acid (a PHA) and sodium hyaluronate (a moisturiser), making it perfect for keeping the skin healthy and hydrated.
This pH-balancing facial mist uses gluconolactone, not to exfoliate but to protect the skin. The goal of this mist is simple: to keep your skin at the optimal pH for it to stay healthy.
This exfoliating sleeping mask can be used as the final step in your PM routine instead of moisturiser (no need to wash it off!). This 5% PHA mask works to even texture, clear blemishes and moisturise the skin through the night.
This facial cleanser is a gentle, soap-free exfoliant that removes impurities and makeup without drying out the skin. It is suitable for all skin types, particularly dry, sensitive or rosacea-prone skin.