AHAs & BHAs: Chemical exfoliation for removing dead skin cells and fighting off bacteria. But which one is right for you?


AHAs and BHAs: What’s the Difference?

— We explore chemical exfoliants as a means to remove dead skin cells and fight off bacteria. But which one is right for you?



Tash Havos
Content Writer/
Product specialist


A new generation of acid exfoliators have made their way into the mainstream. In the past, this type of exfoliation was something skin specialists and beauty therapists only could provide, however with the ban of micro-beads and sensitive skin types on the rise, chemical exfoliation has become the go-to in sloughing off those dead skin cells in the comfort of your own home.

To put it plainly, exfoliants on the market mainly run in two lanes: physical and chemical. Physical exfoliation is the type that requires scrubbing action, usually a product that has a grainy, textured consistency, or a tool like a dry brush. Chemical exfoliants are acids that are added to products like serums, lotions or even soaked pads. They can seem quite overwhelming because, well, how often do we confidently and knowingly use acid-based chemicals on our face? Particularly if you have sensitive, dry or brittle, or problematic skin, it’s normal to feel these could be too abrasive for you.

And they might be, too. I’m not here to tell you that you absolutely need these to exfoliate, as there are other methods that may work better. However, it’s best to have all the information on what they do in case you’re planning to start.

For now, we’re focusing on chemical exfoliation. This category is broken down into two subcategories: AHA and BHA. 

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AHAs, also known as Alpha Hydroxy Acids.

These work on the surface of the skin, gently dissolving dead skin cells to make way for a soft, smooth, and more refined surface underneath. As AHAs are water-soluble, they don’t penetrate deep below the surface of the skin, making them great for dry or sun-damaged skin types. Despite their water-solubility, AHAs don’t have a large molecular size, making it easy to find their way just underneath the surface of the skin, enough to reduce the effects of hyperpigmentation – such as acne scars and dark spots.

Types of AHAs are:

Glycolic acid

The most common type of AHA. It’s made from sugar cane, and provides significant exfoliation. Its antimicrobial properties may help prevent acne breakouts.

Lactic acid

Another common AHA. Lactic acid is made from lactose in milk, and known for its exfoliating and anti-ageing effects.

Tartaric acid

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Lesser known, and made from grape seed extracts. This acid is useful in alleviating signs of sun damage and acne.

Citric acid

Made from citrus fruit extracts. Its main role is to neutralise the skin’s pH levels and even out textured skin.

Malic acid

Also lesser known, but is a type of AHA-BHA crossover. It’s made from apple acids. It’s not the most effective acid when used on its own, but it could be a great addition to make other acids more effective.

Mandelic acid

Contains larger molecules derived from almond extracts. Used alone, the acid may improve texture and pore size, however can be added with other acids for increased exfoliation.

BHA, also known as Beta Hydroxy Acid.

There is only one real BHA – known as Salicylic acid. This is an oil-soluble acid, meaning it can penetrate beneath the skin’s surface to clean out excess sebum found in the pores.

Salicylic acid also has anti-inflammatory and antibacterial properties so those who suffer from breakouts and blackheads may find this is the acid they’ve been waiting for.

There is one more, less well-known acid in the clan - known as PHAs.

PHAs are also known as Polyhydroxic acids. They work similarly to AHAs but are larger in molecular size. PHAs will find it much harder to penetrate the skin, meaning it’s less likely that you will see any negative side effects from this acid. If you suffer from sensitivities, this might be one you could tolerate. Look for gluconolactone and lactobionic acid on the ingredients listing.

Image via  @sansceuticals

Image via @sansceuticals


Different Intensities of Chemical Exfoliation

It’s important to note that chemical exfoliants also vary in intensity – mild, medium or intense exfoliation – depending on their main ingredients.  

Mild exfoliants may have ingredients like Aloe Vera, Ginseng, Botanical extracts or Oat extracts to soothe, nourish, and protect.

Medium chemical exfoliators would be along the same vein as the well-known Dr. Dennis Gross Skincare Alpha Beta peels. These types of exfoliants may induce redness for around 20-30 minutes after, and you might even notice some dryness or flaking over the following few days.

In medium chemical exfoliants, when Lactic acid is involved as the AHA component rather Glycolic acid, the formula may be less irritating and just as moisturising.

Intense chemical exfoliants have both AHA and BHA in the formula, increasing collagen production, in turn making the dermal layers physically plumper. This type, however, is not recommended for beginners. Remember, what’s mild for one person may be extreme for the next. This type of exfoliant is something that you can build up to, but I would not recommend starting here, even if your skin is quite resilient.

Frequency of Exfoliation

Depending on your skin type also depends on how frequently you use chemical exfoliants. Generally speaking, no more than 1-2 times a week should be more than enough.

And, Don’t Forget!

SPF is non-negotiable. Removing part of the dead skin layer exposes you to sun sensitivity, so do ensure you’re wearing protection during the day, even in winter.



Do you use chemical exfoliants as part of your routine? What products work well for you?

Do you prefer chemical or physical exfoliation?

Let us know via commenting below.

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