When it comes to skincare, alpha hydroxy acids (AHAs) have gained a lot of popularity in recent years. These powerful, transformative substances are lauded for their exfoliating abilities and the extensive range of skin benefits they offer. Let’s take a closer look at what AHAs are, how they work and separate myth from fact.
What Are Alpha Hydroxy Acids?
AHAs are a group of naturally occurring acids that are derived from various sources including fruits, milk and sugarcane. They work by breaking down the bonds between dead skin cells on the surface, which lets these cells slough away easily. This exfoliating action helps improve the skin’s texture and tone. The result looks smoother, more evenly toned and radiant. For a fuller picture of how AHAs sit alongside BHAs and PHAs, see our guide to the different exfoliating acids.
What Are the Benefits of AHAs?
Most of the appeal of AHAs comes down to a few well-studied effects. These are the main ones:
- Smoother texture and fewer fine lines: as we age, our skin sheds dead cells more slowly, which leaves a dull, rough build-up that can emphasise lines. By speeding up this turnover, AHAs smooth the surface and soften the look of fine lines and wrinkles.
- A more even tone: with regular use, AHAs help fade uneven tone and hyperpigmentation such as age spots and sun spots. They do this by promoting the growth of new, healthy skin cells.
- More collagen and firmness: research shows AHAs can stimulate collagen production and increase skin thickness. This improves elasticity and reduces the look of thin, sagging skin. A 2024 review found that glycolic and lactic acids boost both collagen and elastin.
Which Skin Conditions Do AHAs Treat?
AHAs are also effective at treating a range of skin conditions, including acne, rosacea and melasma. They are often used in acne because they smooth texture and even out skin tone. This helps with the post-inflammatory hyperpigmentation and scarring that acne leaves behind. AHAs are not oil-soluble, however. So clinicians turn to beta hydroxy acids (BHAs) instead, to clear pores and regulate oil in people with active acne. AHAs can also help reduce the redness and inflammation associated with rosacea. They can lighten the dark patches caused by hereditary hyperpigmentation or sun damage (melasma).
Where Do You Find AHAs in Skincare?
AHAs are available in a range of skincare products, including cleansers, toners, serums and moisturisers. They can be found in both over-the-counter and prescription-strength products. Given the amount of choice in terms of types, strengths and formulations, it’s a good idea to consult a skincare professional before using AHAs. This helps ensure you’re using the right strength and type for your specific concerns and aims.
What Are the Different Types of AHAs?
When it comes to AHAs, you’re spoilt for choice. There are many different types, each with unique characteristics and benefits:
- Glycolic acid: derived from sugarcane, this is probably the most famous and widely available AHA. It has the smallest molecule of the AHAs, so it penetrates deeply and quickly. This makes it a powerful tool for fine lines, texture and dullness. The same property also makes it more irritating, with a higher risk of damage if you use too strong a concentration. Our glycolic acid guide covers it in detail.
- Lactic acid: sourced from milk, lactic acid is milder and more suitable for sensitive skin. It helps improve skin texture and smoothness, as well as reduce hyperpigmentation.
- Mandelic acid: derived from bitter almonds, mandelic acid has a larger molecule, so it doesn’t penetrate as deeply and is less likely to cause irritation. This makes it a great option for sensitive skin, skin of colour or rosacea.
- Citric acid: made from citrus fruits, citric acid works as an antioxidant and helps neutralise damaging free radicals.
- Malic and tartaric acids: sourced from fruits like apples and grapes, malic and tartaric acids supplement more active AHAs like glycolic and lactic acid, boosting their efficacy.
The type of AHA that is best for you depends on your specific skin needs, skin type and sensitivity.
What Are the Side Effects of AHAs?
AHAs can cause some side effects, including dryness, redness and irritation. These are generally mild and can be managed by using a moisturiser and avoiding prolonged sun exposure. It’s also important to use sunscreen when using AHAs, as they can increase the skin’s sensitivity to the sun. People with sensitive skin and skin of colour need to be particularly careful (especially with smaller AHAs like glycolic acid, which penetrate deeper). This is because skin irritation can occur. As a result, you may end up with minor burns and post-inflammatory hyperpigmentation.
AHAs are a powerful tool in skincare, providing a range of benefits for the skin. They can improve the appearance of fine lines and wrinkles. They also improve the tone and texture of the skin and help treat a range of conditions. With proper use and careful consideration of potential side effects, they can be a valuable addition to any skincare routine.
At City Skin Clinic, we are passionate about personalised skincare. Our online clinic offers safe and effective treatments using ingredients like tretinoin and hydroquinone where appropriate. Our doctors treat skin conditions like acne, hyperpigmentation, melasma and skin ageing. To start your personalised plan, book a virtual video consultation or use our online consultation form. The journey towards great skin and hair starts here.
This article is intended for general informational purposes only and is not a substitute for medical advice, diagnosis or treatment. Always consult a qualified medical professional with any concerns about your skin or treatment options.
