What are PHA's (Polyhydroxy Acids)?

What are PHA's (Polyhydroxy Acids)?

Elise Parkes
4 minute read

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What are PHA’s (Polyhydroxy Acids)?

Resurfacing, refining, glow inducing. If you are anything like us, you L O V E an acid. The apple of the beauty industry’s eye for a while now, you’re probably familiar with AHA’s (glycolic, citric, lactic) and BHA’s (salicylic, tropic) but there’s a new kid on the block and it’s about to take over… Meet Polyhydroxy Acids aka PHA’s.

So what are PHA's? Often naturally derived, this chemical exfoliant is incredible for resurfacing the skin’s surface, resulting in a more even tone and texture, whilst also being antioxidant-rich and suitable for sensitive skin. Sounds pretty incredible right? Let’s get into the details…

What is PHA in skincare?

Polyhydroxy acids — aka PHAs — are chemical exfoliants, similar to AHA’s (they’re considered their next generation cousins) they work by exfoliating dead skin cells on the surface, evening skin tone and texture. For those of you who find AHA’s or BHA’s too aggressive, PHA’s are perfect for sensitive skin and can even be used in conjunction with retinols.

They also help the skincare you follow with to penetrate deeper, therefore work harder and more efficiently. Although they’re pretty new to the skincare world, the most common PHAs are gluconolactone (found in the Pure Clarity range), galactose, and lactobionic acid and you’ll tend to find PHA’s in items like toners, cleansers or serums.

Apart from being incredible at resurfacing, they also fight glycation (an ageing process that weakens your collagen), are antioxidant rich and are humectants, meaning they help skin retain moisture, strengthening the barrier function.

Benefits of PHA

So you know what they are and how they work, but what are the benefits of PHA?

Resurfacing – chemical exfoliants they gently resurface the skin, resulting in a more even tone and texture, and a clarified glowing complexion.

Balancing – they help balance the production of sebum, making them perfect for acne prone of oily skin.

Suitable for sensitive skin: PHA’s are a lot gentler on the skin because they have a larger molecule size. If you have sensitive skin, you'll probably be able to apply a PHA with little-to-no stinging or irritation.

Non-drying - PHAs are actually humectants (meaning they retain moisture reserves) so they’re incredible for resurfacing skin and tackling breakouts without being drying.

Antioxidant rich - yes, we love them for their exfoliating properties, here at Scientia they’re personally our favourite acid, since they also boast anti-inflammatory and antioxidant properties.

Anti-ageing- So PHA’s can actually help fight glycation, this is a process where digested sugar permanently attaches to the collagen in your skin and can weaken it along with elastin levels. So, fighting it can help keep skin looking fresh and youthful.

PHA's vs AHA’s and BHA’s

So how are PHA’s any different that AHA’s and BHA’s? Well… their main difference is down to their molecular structure. The molecules in PHA’s are much larger, therefore cannot penetrate as deeply, working exclusively on the surface without disturbing the deeper delicate layers. This means they work harder to resurface those top layers of the skin, acting as a humectant to strengthen your skin’s barrier all whilst being suitable for those of you who are on the more sensitive side, offering less irritation.

The best products with PHA

As you might be-able to tell, we’re big fans of PHA, which is what inspired our latest launch, meet Pure Clarity and our NEW Deep Clean PHA Cleanser and Purifying PHA Skin Tonic (aka a PHA Toner). Easy to slot into your existing routine, and suitable for those on the sensitive side,  for decongested, clarified & clear-ly glowing skin. ​

Fragrance free and powered by hero actives - think PHA Succinic Acid, Niacinamide, Sacred Lotus Extract, Calamine, Green Tea and more. Transform breakout-prone complexions and put an end to excess oil and blemishes without drying skin out… ​

Pure Clarity Deep Clean PHA Cleanser

Pure Clarity Deep Clean PHA Cleanser


De-congest. Deep clean. Re-hydrate. A gentle PHA purifying cleanser, remove dirt and impurities, refine your complexion and help balance breakout prone skin. With squalane and glycerin for a moisture barrier boost. With Succinic (a naturally occurring and gentle PHA) known… Read More

Pure Clarity Purifying PHA Skin Toner

Pure Clarity Purifying PHA Skin Toner


Breakouts. Congested pores. Uneven texture… restore balance and refine your complexion with a powerhouse blend of PHA (2.5%), Niacinamide (3%) and rejuvenating Sacred Lotus Extract. Powered by natural PHA Succinic Acid to encourage cell rejuvenation and help overturn dead skin cells, it’s… Read More

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