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The Science Behind Skincare Acids
Words The Skin Scientist
Skincare acids aren’t as scary as they sound and in fact, will elevate your skincare routine. If you rewind back to chemistry class, you’ll remember that according to the pH scale acids have a low pH, bases have a high pH and anything in the middle (at pH 7) is neutral. Skincare acids are named with the pH scale in mind, as they’re all ingredients that have a low pH level. But there are quite a few different types of skincare acids, so how do you know which one is right for you? In this article, The Skin Scientist, a MSc Biochemist with experience in the skincare industry, is going to dive into the most popular types of acids, to help you understand which ones are for you and how to introduce them into your skincare routine.
Glycolic acid belongs to a family of exfoliating acids, known as Alpha Hydroxy Acids (AHAs). These acids are easily absorbed by your skin’s outermost layer and usually sourced from fruit, milk or sugar. They work by dissolving the bonds between your dead skin cells to reveal the new healthy layer underneath. This speed ups your natural skin cell renewal process, which can slow down as you age. Therefore, you should incorporate glycolic acid into your skincare routine to reduce the appearance of emerging fine lines and wrinkles, fade hyperpigmentation and achieve a smoother and brighter complexion. Compared to other AHAs, glycolic acid has the smallest sized molecules, meaning that it’s absorbed deeper into your skin and has the highest risk of irritation. So, introduce glycolic acid into your skincare routine slowly, using it twice a week to begin with. You should apply it after cleansing and before other serums/oils and moisturiser, in the morning or at night. If you have sensitive skin or find glycolic acid too irritating, try lactic acid instead. This is a gentler member of the AHA family, so may take a little longer to see results.
Another type of exfoliating acid that may already belong on your bathroom shelf is salicylic acid. Originally derived from willow bark, it belongs to a whole different acid family – the Beta Hydroxy Acids (BHAs). This type of acid dissolves easily in oil, meaning that it can exfoliate deep within your pores. Here, it works by dissolving trapped sebum (oil), dead skin cells and debris, helping to reduce non-inflammatory breakouts, such as whiteheads and blackheads. In addition to these incredible properties, salicylic acid also helps to regulate your skin’s natural sebum production, therefore making it best suited for oily and acne-prone skin, or for those of you who experience mild to moderate breakouts. It’s recommended to start introducing salicylic acid into your skincare routine a few times a week to begin with, in the morning or at night, but not both. You can introduce this ingredient into your routine in many ways; using a salicylic cleanser as your first step, a BHA exfoliant/toner as your second step or as a spot treatment, before moisturising. If your skin begins to feel dry, irritated or tight after application, don’t be alarmed. This is a common side effect of salicylic acid, so just make sure you don’t overdo it and never skip the moisturiser.
AHAs and BHAs aren’t the only types of acids in skincare. There’s also a family of skincare acids that don’t exfoliate your skin, called dicarboxylic acids. One of the most popular types is azelaic acid. It’s anti-inflammatory, antibacterial and an antioxidant, meaning that it neutralises free radicals, unstable molecules that damage your skin’s cellular DNA, so protects against premature skin ageing. This acid also benefits your skin by smoothing your skin’s surface and unclogging pores to reduce breakouts. Azelaic acid has the ability to fade hyperpigmentation, by inhibiting the enzyme - tyrosinase, which produces melanin pigment in your skin. These properties make azelaic acid especially beneficial for those who are acne-prone and experience post-inflammatory hyperpigmentation (PIH) following a breakout. The best thing about this acid is that it doesn’t have any side effects, so is compatible with sensitive skin and skin conditions, such as rosacea. Introduce it into your morning or evening skincare routine, before moisturising and feel free to layer it with other skincare acids and actives, due to the minimal risk of irritation.
You’re probably wondering where hyaluronic acid fits into all of this? So, technically it is an acid because it has a lower pH level, however in skincare it’s actually considered a humectant ingredient. This is because it possesses incredible hydrating properties. Hyaluronic acid works by holding onto water molecules close to your skin’s surface, helping to plump your skin, minimise the visibility of fine lines and reduce moisture loss, through a process known as transepidermal water loss (TEWL). Incorporate it into your morning and evening skincare routine, by applying it before or with moisturiser for the best results.
So now that you know the science behind the skincare acids on your bathroom shelf, you can begin to incorporate them into your skincare routine with confidence. The key thing to remember is that patience is key. Whilst acids will help you to achieve your individual skin goals, there’s no rush or need to apply them to your face all at once.