AHA, BHA and PHA acids are among the most widely used active ingredients in modern skincare. They can be found in serums, toners, exfoliating treatments and cleansers, and are best known for their role in exfoliation – the process of removing dead skin cells from the surface of the skin.
Although they are often grouped together as “skincare acids”, they do not all work in the same way. Each type has its own characteristics and may be better suited to particular skin types or concerns.
So, what is the difference between AHA, BHA and PHA acids, and how do you choose the right one?
Dead skin cells naturally build up on the skin’s surface over time. Exfoliation helps support the skin’s natural renewal process and can contribute to a smoother, fresher-looking complexion.
Regular exfoliation is often associated with:
However, more exfoliation does not automatically mean better results. Overusing exfoliating acids can lead to irritation and may compromise the skin barrier.
AHAs (Alpha Hydroxy Acids) are water-soluble acids that work primarily on the skin’s surface.
They are commonly used to address:
Some of the best-known AHAs include:
Each offers slightly different benefits and levels of intensity.
Glycolic acid is one of the most recognised AHA acids.
Because it has a very small molecular size, it can penetrate the skin more effectively and is often considered one of the more intensive forms of chemical exfoliation.
While many skin types respond well to it, sensitive skin may not always tolerate it as easily.
Lactic acid is generally regarded as a milder AHA.
In addition to its exfoliating properties, it is often associated with supporting skin hydration, making it a popular choice for dry or sensitive skin.
BHAs (Beta Hydroxy Acids) are oil-soluble, allowing them to work not only on the skin’s surface but also inside the pores.
The most well-known BHA is salicylic acid.
Its ability to penetrate pores is one reason why BHA is frequently associated with:
For this reason, BHA acids are particularly popular in skincare routines designed for problematic or congested skin.
PHAs (Polyhydroxy Acids) are generally considered the gentlest group of exfoliating acids.
Their larger molecular structure means they penetrate the skin more slowly and are often better tolerated by sensitive skin types.
Well-known PHA acids include:
Their gentle nature is one of the reasons they have become increasingly popular in Korean skincare.
The most suitable acid depends largely on your skin type and individual concerns.
In general:
Every skin type is different, however, and there is no one-size-fits-all solution.
Yes, but with care.
Some products combine multiple acid types to target several skin concerns at once.
When introducing exfoliating acids into your routine, it is usually best to start gradually and monitor how your skin responds.
Excessive exfoliation can lead to sensitivity and disruption of the skin barrier.
The ideal frequency depends on the product, its concentration and your skin’s tolerance.
Beginners often start with once or twice a week and adjust gradually based on how their skin responds.
In skincare, less is often more.
Consistency and a gentle approach are usually more important than aggressive treatment.
Yes.
Exfoliating acids can increase the skin’s sensitivity to sunlight. That is why daily SPF is considered an essential part of any routine that includes active ingredients.
Sun protection helps defend the skin against UV damage and supports long-term skincare results.
Without regular SPF use, achieving and maintaining desired results can be more challenging.
Exfoliating acids are often paired with ingredients that support hydration and help maintain a healthy skin barrier.
Popular companions include:
When combining acids with other active ingredients, such as retinoids, it is advisable to proceed carefully and monitor your skin’s response.
Exfoliating products are typically applied after cleansing and before moisturiser.
A simple evening routine might look like this:
Cleanser → AHA/BHA/PHA product → Hydrating serum or moisturiser
The following morning, remember to apply SPF.
AHA, BHA and PHA acids are among the most popular active ingredients in modern skincare. Although they all fall into the category of exfoliating acids, each works differently and may be better suited to different skin concerns.
The key to success is choosing the right acid, introducing it gradually and maintaining consistent sun protection.
In skincare, the most effective product is not necessarily the strongest one, but the one that suits your skin’s needs and can be used consistently over the long term.
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