Glycolic acid, one of the most common AHAs (alpha hydroxy acids) in beauty, has grown in popularity over the last decade. Known for its brightening and rejuvenating power, glycolic acid does everything from even out hyperpigmentation to helping reverse the signs of sun damage and ageing – giving the dullest skin that sought-after glow. It can even reduce product buildup on the scalp.
Put simply, it works wonders, but with the plethora of glycolic acid concentrated beauty products out there, it is important to know what it is, how it works and how it could be of benefit to you.
To help us understand this gold standard ingredient best, we’ve enlisted the guidance of medical consultant and founder of Adonia Medical Clinic, Dr Ifeoma Ejikeme, founder of science-led skincare brand Dr Sam’s Skincare, Dr Sam Bunting and Jenny Maånsson, product developer and chemist at hair care brand Maria Nila.
Here, they give us the lowdown on one of the best ingredients proven to help transform your skin, body and hair for good.
What is glycolic acid?
“Glycolic acid is an alpha-hydroxy acid (AHA) derived primarily from sugar cane. It’s well-known in the skincare industry for its small molecular size, which allows it to penetrate the skin effectively,” shares Dr Ejikeme. Although they can be found in all sorts of products, Dr Bunting opts to use them in a particular way, “I prefer them, as I do most things, in the form of leave-on serums, creams and gels so you can get a more sustained, measurable and predictable result from them,” she shares.
What does glycolic acid do?
Acting primarily as an exfoliant, glycolic acid helps to remove the outermost layer of dead skin, known as the stratum corneum. “This can help to improve the skin’s appearance, making it look brighter and more even in tone,” says Dr Ejikeme, who adds that glycolic acid can also help stimulate collagen production, which is beneficial for reducing the appearance of fine lines.
The benefits of glycolic acid are endless, as Dr Bunting goes on to further explain that it can help to refine the texture of skin, leading to a brighter and smoother complexion. “They also function as humectants, attracting water into the skin, thus hydrating it,” she explains. “And on top of all of that, these hard-working acids can also increase the penetration of other active ingredients, which can increase their efficacy.” Dr Bunting states that when you use higher percentages of stronger acids (like glycolic acid), you can also see increased collagen production.
How do we use glycolic acid within our skincare routine?
Glycolic acid can be found in various skincare products, including cleansers, toners, serums, and creams, but what percentage should you go for? If you are new to glycolic acid, start with a low concentration (around five to 10 per cent) and use it once or twice a week.
“Apply glycolic acid after cleansing your skin,” Dr Ejikeme shares. “If it’s in a toner or serum form, apply it with a cotton pad or directly with your fingers, avoiding the eye area. Wait a few minutes before applying a moisturiser to help soothe the skin and restore hydration. Glycolic acid can make your skin more sensitive to the sun, so always apply a broad-spectrum SPF 30 or higher during the day.”
Can you use glycolic acid with retinol?
You can, but with caution. “I avoid layering AHAs and retinoids. Split them out to avoid irritation,” advises Dr Bunting. Dr Ejikeme also shares this sentiment, adding that both glycolic acid and retinol can cause mild skin irritation, particularly when you first begin using them. “If you want to use both, it’s best to alternate them (glycolic acid in the morning and retinol at night, for example) or use them on different days. Always listen to your skin and reduce usage if irritation occurs,” she explains.
What skin type can use glycolic acid?
“Glycolic acid is an easy booster for skin radiance and plays well with other ingredients,” shares Dr Bunting, who adds that it is safe to use provided you’re respectful of its potential for irritancy, due to its strength.
“Glycolic acid is suitable for most skin types, particularly oily skin due to its ability to exfoliate the skin,” says Dr Ejikeme. However, she warns that those with dry or sensitive skin should probably opt for lower concentrations and use products less frequently, while people with very sensitive skin may have to leave it out of their routine altogether.
Can people with darker skin use glycolic acid?
Definitely, but a lower percentage would be best. “Opt for less than 10 per cent and use one to two times a week,” says Dr Ejikeme. “Using a daily sunscreen is crucial to protect the skin and prevent hyperpigmentation.”
Is it safe to use glycolic acid on armpits and knees to help lighten discolouration/hyperpigmentation?
Dr Bunting prefers not to use glycolic acid on her body and instead recommends another ingredient that proves to be more effective. “My preference is for the more gentle AHA lactic acid, which is a bigger molecule and causes less irritation,” she shares.
Is it safe to use anywhere else on the body?
Hair benefits greatly from glycolic acid when used in tandem with other cleansing and protective ingredients. “Reports show that glycolic acid works in the same way on the scalp then it does on skin,” explains Maånsson. “Though, to avoid scalp sensitivity, we choose to use a lower percentage (five per cent) for a gentle exfoliation on the scalp. This avoids redness, dryness or irritation”.
She adds that glycolic acid helps remove buildup and dead skin cells, which leaves hair feeling cleansed and refreshed. Choosing to combine their glycolic acid with other exfoliating AHA’s like lactic, malic and salicylic acid to boost results, Maria Nila tends to add in ingredients like coconut oil, aloe vera and glycerin to scalp cleansing products to increase hydration and protection, which Maånsson says helps decrease the chances of scalp sensitivity, especially when exposed to the sun.
The best glycolic acid products:
Of course, we wouldn’t give you all that information without recommending some places to start. Here are some of our favourite picks for the best glycolic acid products.
Want more info on at home exfoliating treatments? Read our review of the best chemical peels
