Skincare acids are active topical ingredients that are used in formulas for their skincare benefits. They can be plant or animal derived and some are used for exfoliation, some for hydration.

Despite the name ‘acid’, they are not as scary as they sound and are perfectly safe for use on the skin, although they do come in varying concentrations, and some can have a more intense effect than others.

What are the different types of skincare acids?

Alpha-Hydroxy Acids (AHAs) are water soluble acids that naturally occur in fruits, sugar cane and sour milk. AHAs have an exfoliating effect, as they work to loosen the top layer of skin cells by breaking down the bonds that keep the cells joined together. This encourages the skin to grow more cells, increasing cell turnover and revealing a renewed complexion. They also increase collagen synthesis and help to protect the skin from damage, making them great ingredients for anti-ageing formulas.

Beta-Hydroxy Acids (BHAs) are oil soluble acids, meaning they can go deeper into pores to remove dead skin cells and excess sebum. BHAs work well for oily skin and are often used to improve acne and signs of sun damage because they’re able to penetrate the skin deeper.

Which are the major skincare acids?

Glycolic Acid

This AHA is well known for its ability to help shed dead skin, while also increasing skin hydration. It’s the smallest type of acid so is very effective at getting into the skin and targeting signs of ageing like fine lines. It can also help with mild hyperpigmentation and enlarged pores.

Tartaric Acid 

Due to its antioxidant and exfoliation properties, the AHA tartaric acid is most often used for reducing fine lines and wrinkles, hyperpigmentation, acne, large pores, and dull/uneven skin tone.

Salicylic Acid 

Treats acne by reducing swelling and redness and unplugging blocked skin pores to allow pimples to shrink. It treats other skin conditions by softening and loosening dry, scaly, or thickened skin so that it falls off or can be removed easily.

Lactic Acid 

Helpful for smoothing and softening rough or scaly skin while also being gentle and hydrating.

Citric Acid 

Citric acid works by exfoliating the upper layer of dead skin cells to help clean pores, even skin tone and soften and smooth the skin.

Which skincare acids should not be used together?

You do need to be careful as you can easily dry out the skin. It’s best to use either AHAs or BHAs separately rather than combining them, to avoid irritation. For example, glycolic acid (AHA) and salicylic acid (BHA) are best used separately but you can use glycolic acid with mandelic acid which is also an AHA.

It’s also best not to layer retinol or vitamin C with AHAs and BHAs as this could seriously affect the moisture barrier. The best way to use acids alongside retinol would be to do ‘Skin Cycling’ – alternating them each evening, so that you’re not overloading the skin.

Does potency make a difference in skincare acids?

The concentration will help determine how strong the product is–if you have sensitive skin or are just starting out with acids, you may want to start with a lower concentration like 5-7 per cent, which you can gradually build up to 8-10 per cent. Depending on your skin type, you may find that a higher concentration irritates your skin or you may find it works wonders for exfoliation.

In-clinic we use 20-30 per cent concentrations for chemical peels, but these should only be used by professional clinicians as they are powerful exfoliants. The pH of the product will also determine its potency–a pH of 3-4 is best. The individual strength of the acid along with the product formula will alter its effectiveness.

Which skincare acids are suitable for each skin type?

AHAs are recommended for dry or sun damaged skin as they are able to exfoliate while helping the skin’s surface to retain moisture. They’re good for addressing hyperpigmentation, whereas BHAs are better for oily and acne prone skin. If you suffer from acne but also experience dry skin, you might wish to use both AHAs and BHAs, cyclically.

Is there anyone that should not use skincare acids?

Different acids are suitable for different skin types, concerns and conditions, so it’s important to research before using, to avoid irritating the skin. For sensitive skin especially, you need to be careful with how harsh the acid is and the concentration. You’ll also need to be religious with your SPF application when using acids as they can make your skin more susceptible to sun damage.

What are the side effects of overusing skincare acids?

Overusing acids, layering the wrong active ingredients or using the wrong acid for your skin type can result in dryness, flaking skin, irritation, redness or inflammation. This is why it’s super important to start with gentle products, lower concentrations, cycle your skincare and research active ingredients.