A Simple Guide To Skincare Acids (AHAs & BHAs) And How To Integrate Them Into Your Regime

Introducing an ingredient with the word ‘acid’ in the name can feel overwhelming, scary and a bit baffling. Acids are increasingly hailed as skin ‘heroes’ that have the potential to change the appearance of your complexion (in a positive way!) but if used incorrectly they could leave your skin feeling irritated and inflamed; they’re not ingredients to be used lightly, but they can deliver exceptional results no matter your skin type, age or concern – if you know what you’re doing. But how can an acid benefit your skincare regime, I hear you ask? Here’s my guide on how to use skincare acids and a breakdown of each in turn…

How To Use Skincare Acids & Integrate Them Into Your Regime

Acids (commonly known as AHAs & BHAs) can help loosen or dissolve the ‘cement’ between dead cells to brighten dull skin, unblock pores, reduce the appearance of fine lines, smooth and refresh the overall appearance of your complexion; they’re essentially providing a cumulative non-manual exfoliating action, providing a much healthier looking result in the long term. The key is patience, as you may not start to see the results for a number of weeks!

The main difference between AHAS (Alpha Hydroxy Acids) and BHAs (Beta Hydroxy Acids) is simply that the former is water soluble and the latter is oil soluble; they’re both great at what they do, but they have slightly different uses (which we’ll come on to later.) Within those categories there are acids known as lactic, salicylic, glycolic, azealic, mandelic and malic, all of which can be used for different purposes depending upon your skin need.


Out of all the acids, lactic acid is the most gentle and more suited to those with sensitive skin. Its molecule is big enough for slow and gentle absorption into the skin, minimising irritation or sensitivity that’s often found with other AHAs. It also offers added ageing benefits (including stimulating collagen synthesis, improve skin texture and reducing hyperpigmentation,) as well as being a humectant (it absorbs and holds in moisture.) It’s great if you’re looking to target dullness, ageing skin or general pigmentation issues and I’ve personally seen great results from it.


What’s special about this ingredient is that it’s oil soluble, meaning it can penetrate the skin at a deeper level and help to unclog pores. This means it can help to prevent both blackheads and whiteheads when it gets super deep into those hard to reach follicles, great for those with congestion or anyone prone to breakouts. (Although don’t use on broken skin – ouch!) This is often found in products developed for spot-prone skin, and recommended by professionals for that reason.


Derived from sugar cane, glycolic acid’s molecules are small and able to penetrate the skin easily for great results; it’s often the most commonly used acid, and remains a favourite within professional skin peeling treatments. It’s also the main ingredient in the cult Pixi Glow Tonic that has millions of fans around the globe, thanks to its ability to brighten the complexion and reduce the appearance of pigmentation. (Read my first ever feature on it here!) Due to its size it can deliver great results pretty quickly, but it’s not necessarily suited to more sensitive skin types.


Definitely an under-the-radar acid, azelaic acid has been found to significantly diminish the appearance of skin blemishes, help fade pigmentation and scarring, refine the skin’s surface, and even reduce skin sensitivity. It’s said to work by ‘inhibiting misbehaving elements’ within the top layers of the skin, allowing cells to respond more favourably in order to provide a much more radiant looking complexion. Although it does also gently exfoliate the skin, it doesn’t do so as effectively as ingredients such as glycolic or lactic acid so it can be used in tandem with them for maximum results. This seems to be an acid suited to all complexions, ages and issues, although it’s not as commonly known as the others.


These two acids have far bigger molecules than that of lactic and glycolic acid, but they work in a very similar way; they’re often used as supplementary AHAs as they penetrate the skin at different speeds and therefore work at different levels. They’re far better for those with sensitive skin, but their results will be seen far slower as a result. If you’re wondering how to use skincare acids, then this is probably the one ingredient you shouldn’t need to worry about.


Although known as an acid, this acts in a completely different way to the rest – but it’s still an essential part of any ‘anti ageing’ skincare regime. Young skin is smooth and elastic as it contains large amounts of Hyaluronic Acid, which helps keep the skin looking and feeling healthy. It provides continuous moisture by binding up to 1000 times its weight in water, but with age the ability of the skin to produce this vital substance decreases. Hyaluronic Acid acts as a ‘space filler’ by binding to water, therefore keeping the skin plump and healthy looking.

How To Use Skincare Acids & Integrate Them Into Your Regime

Now you know the differences between the acids, you can pick the one/s that are most well suited to your needs and integrate them into your existing regime; there really is an acid for everyone, no matter your age, skin type or overall concern.

It’s worth noting that acids can come in different formats (liquid toners, masks, serums, treatments) and concentrations (often between 1% and 10%) and that not one fits all; it’s also worth starting out small (i.e. once a week) and building up to more regular use as your skin starts to respond and gets used to the ingredient – that’s where the majority of issues develop, when we pile on the acid due to impatience and our skin goes into meltdown!

Acids don’t need to be scary if you arm yourself with the knowledge to choose and use wisely; I hope this breakdown has helped you understand how to use skincare acids within your regime and encouraged you to give them a go.

How To Use Skincare Acids & Integrate Them Into Your Regime

How to use skincare acids in your skincare regime.


  1. Lesle
    July 15, 2019 / 2:46 pm

    Wondering if you’d do a post on roseacea?

    • hayleyhalluk
      July 16, 2019 / 4:41 pm

      I’ve written about it before but it’s not really my area of specialism to be honest.
      My very good friend Lex has rosacea and blogs a lot about her tips / products if you want to check her site out here though: https://talontedlex.co.uk/ She’s much better placed than I!

  2. Danish Pastry
    July 15, 2019 / 6:35 pm

    I’ve become a bit of an acid adict, and use the ones you’ve mentioned reugularly (except for mandelic and malic acid). Salicylic has been on my radar for years, but the others are fairly new to me and I must admit to loving The Ordinary products as they’re so affordable. Hyaluronic stoped my skin being dry and flaky in the winter, and generally my skin seems brighter – I think I can see a difference if I’m not consistent in my routine!
    It’s great to see a guide on these, as it can be confusing, especially when it comes to combining them! I tend to use a glycolic toner first, then no more than three of the more serum like acids. Glycolic and lactic I use in the evening as they’re supposed to make your skin more sensitive to the sun. And I finish with a moisturiser, to lock in the hyaluronic, especially in dryer weather.
    As I said, I’m an adict…

    • hayleyhalluk
      July 16, 2019 / 4:42 pm

      Ahhh yes, that’s so important – either only use at night or make sure you use SPF religiously in the day (you should be using it anyway, but be extra careful if using acids!) It can be so confusing and I know I’ve been asked to break down acids by readers a few times; especially as The Ordinary offers lots but isn’t great at explaining what they do or how you use them.

      • Danish Pastry
        July 20, 2019 / 12:02 pm

        I’ve found some great advice on you tube, helped get my head around it!

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