AHAs (fruit acids): what they really do for your skin

They appear on many exfoliating and anti-aging skincare products, sometimes under intimidating names: glycolic acid, lactic acid, mandelic acid. These AHAs, or alpha hydroxy acids, are among the most extensively studied exfoliating ingredients. But what do they actually do for the skin?

AHAs work on the skin's surface to remove dead skin cells, which helps smooth the skin's texture, restore radiance, and even out the complexion. Here's how they work, their real benefits, and how to get the most out of them without irritating your skin.

What are AHAs?

AHAs (alpha-hydroxy acids) are organic acids that occur naturally in many fruits and products, which is why they are also known as fruit acids. The best-known ones are glycolic acid (derived from sugarcane), lactic acid (from milk), citric acid, malic acid (from apples), and tartaric acid (from grapes).

What sets them apart is that they are water-soluble, which means they act primarily on the skin's surface. This is what distinguishes them from BHAs, such as salicylic acid, which are fat-soluble and penetrate deeper into the pores.

How do they operate, and what do they actually do?

AHAs work in an elegant way: they weaken the bonds that hold dead skin cells together on the skin’s surface, facilitating their natural shedding. This gentle, friction-free exfoliation reveals fresher, more even-textured skin.

The benefits, confirmed by the scientific literature, go beyond simple exfoliation. AHAs refine the skin’s texture, smooth the skin’s surface, restore radiance to a dull complexion, and help even out skin tone. When used regularly, they can improve the appearance of the epidermis and dermis and stimulate skin renewal. At low concentrations, they also have moisturizing properties, acting as humectants. Finally, by clearing the skin’s surface, they promote better absorption of the skincare products applied afterward.

Not all AHAs are created equal

Each AHA has its own unique characteristics, which are largely determined by the size of its molecule. Glycolic acid, the smallest, penetrates most easily: it is the most powerful and the most extensively studied, making it ideal for radiance and skin texture. Lactic acid, which is slightly gentler, has the added benefit of being moisturizing. Mandelic acid, with its larger molecule, penetrates more slowly and is often suitable for more sensitive skin.

Combining several fruit acids allows you to harness their combined benefits, resulting in an action that is both effective and gradual, and better tolerated by the skin.

Using Them Properly: The Issue of Concentration

With AHAs, concentration is everything. Research sums it up well: depending on their concentration, AHAs can be a friend or a source of irritation. At moderate concentrations and in well-formulated products, they exfoliate effectively while remaining gentle. However, if they’re too concentrated, they can disrupt the skin barrier and cause redness.

So, a few precautions are necessary. Introduce AHAs gradually, avoid over-exfoliating, and support the skin barrier with a moisturizer. Above all, since AHAs can increase the skin’s sensitivity to the sun, daily application of sunscreen is essential—especially since it is the best-documented measure against UV-induced aging.

AHAs in the PERS Triple Exfoliant

The PERS Triple Exfoliant harnesses the power of fruit acids, with 5% fruit AHAs and 5% glycolic acid, in a triple exfoliation system that combines chemical, enzymatic, and mechanical action. To preserve the skin’s softness, the formula is enriched with 5% niacinamide, an active ingredient that strengthens the skin barrier by stimulating ceramide synthesis and helps reduce sensitivity.

This approach allows you to enjoy the benefits of AHAs (radiance, refined skin texture, and a smoother complexion) while being gentle on the skin, including sensitive skin. Use it in the evening, every other night, as an exfoliator or mask, followed by a moisturizer such as the PERS Light Cream, and a PERS SPF 50+ Sunscreen the next morning.

Key Takeaways

AHAs, or fruit acids, are gentle chemical exfoliants that remove dead skin cells from the surface to reveal smoother, more radiant, and more even-toned skin. They can also hydrate the skin at low concentrations and, over time, improve the skin’s appearance. Their effectiveness and tolerability depend on concentration: when used in the right amounts and with the right supporting measures (hydration, sun protection, gradual introduction), they become a valuable addition to a skincare routine, especially when combined with other soothing ingredients to preserve the skin barrier.

Scientific Sources