From Glycolic To Salicylic: Acids In Skincare Explained

Let's break down the ABCs of facial acids.

Admittedly, all throughout my teens and early twenties, I took my almost perfect skin for granted. I was interested in skincare, and as the years went on, I became even more interested. I’d skim through the labels of many, many products, scour the internet for the ‘need to know facts’ about skincare routines, and create myself a little oasis of pampering by smothering my face in oils, creams and lotions.

But it wasn’t until I had my first ever reaction to a skincare product, which threw my skin in to disarray, that I really delved deep into what kind of skincare I was using, and the ingredients I was putting on my face daily. The state of your skin can affect your confidence in more ways than one, so apparent that it can feel like a punch to the gut. But if you’re not a skincare professional, how do you know where to start?

Skincare can be bewildering at the best of times, whether you’re on a quest to find the perfect cleanser, or trying to decide if you really should invest in an eye cream. But then throw acids into the mix and it gets even more baffling. What do they do? Do you need them? How do you figure out which ones to use, if any at all?

Basically, skincare acids refer to treatments and products that have active ingredients, to physically change the looks and feel of your skin. Two of the most popular type of acids in skincare are alpha hydroxy acids and beta hydroxy acids, or as you may have heard of them, AHAs and BHAs. Luckily for us, Jennifer Rock, AKA The Skin Nerd, broke this down for us to explain what the actual difference is.


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AHAs, or alpha hydroxy acids, are water-soluble exfoliating acids. Their water-solubility means that they do some stellar work on the surface of the skin, meaning they may be the preferred exfoliating acid for pigment, scarring and very superficial skin texture. BHA, or beta hydroxy acid, is an oil-soluble exfoliating acid known as salicylic acid, or Sally for short. The benefits of this oil-solubility is that the acid can penetrate into pores and give them a good clear out by dissolving plugs of sebum, dead skin cells and debris. AHAs are usually recommended for the normal-to-dry humans, whereas BHA is the go-to for oily, normal-to-oily and blemish-prone folks.”

We all know the importance of exfoliating your skin at this stage – it’s like giving your face a new lease of life. But a lot of people know that you’re best off exfoliating with an acid, rather than a gritty scrub. Exfoliating acids remove the very top layer of your skin. This can sound like a bit of a no-go area, but this removes the top layer of dead skin, that can be as stubborn as those pub regulars who stay seated comfortably when it’s time for last calls.

Jennifer explains when to introduce these exfoliating acids into your regime, something that may differ for everyone. “For some, exfoliating acids outside of PHA (polyhydroxy acid) may never be an option due to sensitive, reactive skin. For others, it may be perfectly suitable and advisable to start using salicylic acid from 12 years of age or 13 years of age under the advice of a skincare professional! If you are in your 20s and wondering if you should or could introduce exfoliating acids into your routine, the answer is a resounding yes, especially in the mid-20s when everything has (sadly, so very sadly) begun to slow down.”

But what if your skin is crying out for different treatments, we hear you say? Well, don’t fret, you can switch between acids easily. When asked if acids can be used simultaneously, Jennifer had a pretty simple answer, “Absofrickinglutely“.

Explaining further, she says, “some products blend acids like lactic and salicylic acid, for example, for a slightly different effect. However, again, it’s about avoiding over-exfoliation and only using acids as frequently as your skin can actually handle. If you’re a dry-skinned human who gets the odd spot around your period, you may opt for a lactic acid or glycolic acid cleanser 70% of the time and then crack out salicylic acid around your time of the month. Maybe you’re someone still struggling with oiliness but have pigmentation – in this case, salicylic acid may be your go-to but every once in a while, you can do a glycolic acid mask for a bit of an extra brightening boost,” Jennifer says.


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When it comes to how acids change how your skin looks, it all boils down to what condition your skin is in, and what you want to achieve. According to Jennifer, “short term, an exfoliating acid will make your skin feel softer and it will look instantly brighter, it can look smooth, fresh and make skin look more youthful temporarily. Salicylic acid when used regularly will help to reduce breakouts and assist with oiliness. Glycolic acid and lactic acid will help to generally brighten and can reduce the appearance of lines, wrinkles, pigment and any roughness the skin is experiencing.”

It’s very important to be aware it is possible to overuse acids, and you can be left with over-exfoliated skin – not ideal. But how can you spot over-exfoliated skin? Jennifer says, “Over-exfoliated skin can look tight and shiny like a marble countertop, it will have patches of redness or flaking and it may look dehydrated (fine lines and wrinkles may be more noticeable). So, the opposite effects of what we want.“

As well as acids being able to revive your skin, they also pack a punch when it comes to hydration. Everyone needs to add some hydration to their skin. Yep, even if you’re sick of trying to combat oily skin, it still needs to be hydrated. And when it comes to hydrating acids, think the ever so popular hyaluronic and the lesser-known polyglutamic (it’s a pity we don’t have Eva Longoria to sound this one out for us). 


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Hyaluronic acid is naturally produced by your body, and its main function is to retain water so everything is hydrated and well, plump. Your skin’s own produced hyaluronic doesn’t last very long, so adding to it when going about your skincare routine will plump out fine lines, leaving you with silky smooth skin, give your face an all-over glowy look and keep those hydration levels high. Which is always a good thing. Hydration is KEY. Long story short, hyaluronic acid is definitely worth the hype.

Polyglutamic acid, on the other hand, hasn’t had the same levels of fame that our good friend hyaluronic has had. But chances are, you’re going to start hearing a lot more about it. It’s quite similar to hyaluronic, in that it adds hydration, evens out the skin and leaves it silky smooth. The main difference being that polyglutamic acid (or PGA) forms a film on the skin that stops water from evaporating, so it packs an even bigger punch than hyaluronic does. When you’re applying hydrating acids to your skin, always remember to apply them when your skin is damp, this will help to really lock in those uber-important ingredients. Pop it on while your face is still slightly damp from cleansing, or give it a little spritz beforehand and you’ll be laughing your little hydrated face off.

Now that you know everything there is to know about acids, get ready for the best skin of your life.


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