Everything you need to know about glycolic acid (including how often you should be using it)

As well as brightening dull skin overnight, Dr Bowe also points out that “because it's resurfacing the skin it's going to let your other skincare products penetrate better, so they're going to work better for you.”

In a nutshell, glycolic acid is used in the treatment of:

• Acne
• Acne scars
• Pigmentation and sun damage
• Skin dryness
• Bumpy skin texture
• Dull skin

“Clinical trials have shown the effectiveness of this ingredient in reversing the effects of photo-ageing and improving wrinkles, skin elasticity, tone and hydration,” reveals Dr Zamani.

How should you use glycolic acid in your skincare routine?

When it comes to choosing your preferred glycolic product, you’re actually spoilt for choice. “There are so many delivery options of this versatile acid," says cosmetic doctor Dr Jonquille Chantrey. "It's most commonly used in facial cleansers, toners, exfoliating creams and peels. I personally like it in either a wash-off cleanser or an exfoliating cream.”

But there is also a correct way of using glycolic acid to avoid irritation. "I have seen many cases over the years of inappropriate application leading to uneven skin tone areas and even superficial surface scarring,” she adds.

1. Start with a low dose and introduce it gradually. “It's essential to start with a lower concentration and then gradually increase usage frequency as your skin learns to tolerate it,” explains consultant dermatologist, Dr Angela Tewari. “I find a daily wash or serum 2-3 times a week at a 5-10 per cent concentration very helpful.”
2. Avoid using glycolic at the same time of day as retinol. Using them together can disrupt the skin barrier and cause irritation. “This is due to the retinol accelerating cell turnover and the glycolic acid contributing to exfoliation,” says Dr Zamani.
3. Use vitamin C at a separate time of day to glycolic acid. Mohini Patel, Dermatica's lead physical product manager, recommends “introducing glycolic acid and vitamin C one at a time into a skincare routine to allow the skin to adjust before combining them.” If you still want to incorporate those ingredients into your routine, use vitamin C in the morning and glycolic acid in the evening one to three times a week. Better still, consult with a dermatologist or skincare professional before combining different active ingredients in your skincare routine. They can always help you create a personalised routine that is safe and effective for your specific skin type and concerns.
4. Don't use peptides at the same time as glycolic acid. "Peptides should not be used with glycolic acid as this will alter the pH of the skin and reduce the efficacy of the peptides,” says Dr Zamani.
5. Be diligent about daily SPF application. Glycolic acid can make your skin more sensitive to the sun, so make sure to always wear sunscreen – even on grey days as UV rays can penetrate through clouds and windows. “A sunscreen should always be used concurrently,” says Dr Chantrey, who adds that those who aren't prepared to slather on an SPF30+ daily, would be advised not to use a high strength glycolic acid.

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Is glycolic acid good for all skin types?

Glycolic acid is generally considered safe for most skin types, but in the right doses for specific skin types and skin concerns. If you have sensitive skin, it is recommended to use it in lower concentrations and less frequently, or to “perform a patch test on a small area of skin before use,” to see how your skin reacts, says Mohini.

By dissolving the bonds that hold dead skin cells together, glycolic acid is also particularly useful in the treatment of acne-prone skin. “This process helps to unclog pores, preventing the formation of comedones (black/white heads) that can contribute to acne.”

Dull, sagging skin can also benefit. “As the skin ages, cell turnover slows down, so as glycolic acid deeply exfoliates the top layer of the skin, it also reveals a more radiant complexion,” Mohini adds. “The exfoliation stimulates the production of new, healthier skin skin cells including fibroblasts, which are crucial for collagen synthesis.”

Glycolic acid vs salicylic acid for acne

Glycolic acid can be beneficial for acne-prone skin as it helps to exfoliate dead skin cells and unclog pores, reducing the occurrence of blackheads, whiteheads, and pimples. But, according to Mohini, salicylic acid still has the edge for acne:

“While both glycolic acid and salicylic acid share common mechanisms in terms of exfoliation, salicylic acid is oil soluble. It therefore has the ability to penetrate deeply into the pores, effectively exfoliating the follicle lining and removing excess oil and dead skin cells. Furthermore, salicylic acid showcases antibacterial properties, specifically inhibiting the growth of acne-causing bacteria, such as P.acnes, and its anti-inflammatory effect plays an important role in reducing redness and inflammation associated with acne.”

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Does glycolic acid have any side effects?

As with all acids, glycolic comes with some baggage. And due to its low molecular weight, incorrect use can actually prove more problematic than it might with other AHAs. Dr Zamani says: “Overusing glycolic acid can leave the skin red, dry and more sensitive to the sun. This can cause premature ageing, thinning of the skin and heightened risk of pigmentation.”

Skin type must be taken into consideration before you reach for the glycolic. “If you have sensitive skin then it is best to be cautious with some products," Dr Zamani adds. "For example, skin that is sensitive to retinol may also have a similar effect when using glycolic acid."

However, those with eczema or psoriasis should not use glycolic acid, warns Dr Chantry, “as it can increase irritability causing further symptoms.”

Can glycolic acid cause purging?

Purging is a common side effect of using glycolic acid and other exfoliating agents, but it is not experienced by everyone. “Glycolic acid has the potential to cause purging because it promotes cellular turnover – as a result, pre-existing clogs within the pore come to surface more rapidly,” Mohini explains. One solution, she says, is to “introduce glycolic acid at lower concentrations and gradually increase frequency to allow the skin to adjust.”

Purging typically lasts for four to six weeks, after which time, the skin should look clearer and more even-toned. However, if the purging is severe or the skin is becoming excessively dry, irritated, or red, stop the use of the product immediately and speak to a skincare professional or a dermatologist.

Sound like something you might benefit from? Here’s our pick of the best glycolic products available…