Alpha-Hydroxy Acids (AHAs)

Stimulates collagen for skin cell renewal and sloughs away dead skin cells.

Written by
Tori Crowther
Medically reviewed by
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min read
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Alpha hydroxy acid, often shortened to AHAs, is as powerful a skincare ingredient as it sounds. In fact, it’s one of the best for busting blemishes, vacuuming pores and exfoliating dead skin cells to reveal brighter, more radiant skin. 

Sounds pretty great, right? Well, it is. But (and that’s quite a big but so pay attention) there are a couple of things you should know about AHAs before diving right in. It’s fairly easy to overdo it on the AHAs and that’s something you or your skin doesn’t want. 

To make your journey with AHAs as seamless as possible, we’ve put together a guide on everything you could ever want to know about AHAs in skincare. 

What is an AHA?

Alpha hydroxy acid is a chemical exfoliating, water-soluble ingredient, meaning it dissolves in water and can’t penetrate the skin’s oils. There are various types of these acids that fall under the AHA umbrella, which are often made from animal or plant products like sugars, fruit or milk. 

AHAs can be used in a variety of skincare products, including face wash, toners, masks, moisturisers, serums, and even pimple patches.

What's the difference between AHAs and BHAs?

The main difference between alpha hydroxy acids and beta hydroxy acids is that AHAs are water-soluble making them unable to get through the skin’s natural oils.

Beta-hydroxy acids, on the other hand, are oil-soluble, which means they dissolve in oil and can penetrate the sebaceous (oil) glands, below the surface of the skin.  

In addition to this, the 2 types of acids differ due to their molecule size, which essentially means how far deep they can go to get to work into your skin. AHAs have a much smaller molecule size than BHAs. Essentially, the smaller the molecule, the deeper it can penetrate the skin and exfoliate deeper within. 

Now, you’d be forgiven for thinking the deeper the better, but that’s not always the case. Sensitive skin types do better with acids that don’t penetrate too deeply into the skin but still give excellent exfoliating benefits. 

There are various types of AHAs but there’s only one common BHA used in skincare and that’s salicylic acid

BHAs are incredibly effective when used in a cleansing formula — like Software's Salicylic Acid Foaming Wash — to help dissolve those stubborn dead skin cells, control excess oil production, and promote anti-inflammatory properties. 

The 2 can also be combined together to make an extra powerful product. This can make an excellent skincare product if you’re struggling with adult acne as it can combat signs of ageing whilst also unclogging pores to clear breakouts. 

What does alpha-hydroxy acid do?

The main purpose of using AHAs is to exfoliate the skin and slough off dead skin cells.

In doing this, you’ll find that it can reduce hyperpigmentation, smooth fine lines and wrinkles, improve skin texture, unclog pores and minimise breakouts [1].

Is alpha-hydroxy acid the same as hyaluronic acid?

Although both contain the words “acid”, the purpose of AHAs and hyaluronic acid couldn’t be more different. As we mentioned previously, AHAs are used to exfoliate the skin and combat stubborn breakouts and clogged pores. 

Whereas, hyaluronic acid is used as a super hydrator. Able to hold 1,000 times its weight in water, when applied on damp skin before your moisturiser, it gives a boost of hydration. 

These are only similar in that they can help to fight signs of ageing, but they do so in very different ways. 

The good news is that you can use both ingredients together but are not necessary every day. AHAs can be used a maximum of 2-3 times per week (preferably at night), while a hyaluronic acid serum can be used daily.

The different types of AHAs

As we mentioned earlier, there are a bunch of various types of AHAs (just to keep things a little confusing for us all), but here are some of the most popular ones that you’ll likely see included in the ingredient list of your products.

Glycolic acid

This is without a doubt the most popular AHA. Glycolic acid is derived from sugar cane and has one of the smallest molecule sizes of all the AHAs, which means that it penetrates the deepest into the skin.

It’s a strong exfoliator, which gives great results when it comes to fine lines, fading dark spots, improving collagen production and giving an overall radiance. This isn’t an acid for those with sensitive skin types or a compromised skin barrier (think red, inflamed, sore or rashy).

Lactic acid

Lactic acid is derived from, you guessed it, milk. With a slightly bigger molecule size than glycolic acid, lactic acid works as a great exfoliator if you can’t handle glycolic acid on your skin.

It works to retain moisture whilst exfoliating and increasing skin cell turnover. It can also help with the treatment of a skin condition called keratosis pilaris.

Malic acid

Derived from unripe apples and naturally occurring in the body, malic acid is known for smoothing skin texture and fading dark marks on the skin. It’s often used in conjunction with other AHAs, making it an excellent addition to a skincare acid.

Citric acid

It’s a surprise to no one that citric acid is derived from citrus fruits. It does a great job at sloughing off dead skin cells, unclogging pores and revealing brighter skin thanks to its antioxidant properties.

Tartaric acid

Tartaric acid is the antioxidant among the group, and believe it or not, it’s an antioxidant found in wine. Often used for reducing fine lines and wrinkles, promoting a radiant complexion, and regulating pH levels.

What is the strongest AHA?

Due to its molecule size, glycolic acid is considered the strongest acid. This means that it’s got great potential to help you reach skin goals, but due to its strength, it is easy to overdo it.

What are the benefits of AHAs for your skin?

There are dozens of benefits of AHAs for your skin. Removing dead skin cells, gently exfoliating, reducing uneven skin tone, ridding dull skin, promoting new skin cells, and minimising age spots, to name a few.

Helps with gentle exfoliation

AHAs help to chemically exfoliate your skin without the need for harsh physical scrubs. Typically this yields better results for a lot of people.

Improves skin texture

The regular use of AHAs can most certainly improve skin texture as it unsticks the “glue” holding dead skin cells together. This results in a more even skin texture as the cell turnover is improved and dead cells are shed to make way for a radiant complexion.

Promotes collagen production

AHAs can even help promote collagen production through collagen synthesis [1]. Essentially, it helps accelerate the ridding of old collagen and makes way for new. 

Can I use AHA products if I have acne?

Yes, you can! In fact, it’s one of the best ingredients to help reduce your acne; even better if it's combined with salicylic acid (which is a BHA). But, of course, there are rules. 

The first is to not use too many acids at once, or too frequently. Start by using an exfoliating wash 2-3 times per week, like Software's Salicylic Acid Foaming Wash, which works to unclog pores without stripping the skin.

From there, you can try incorporating a toner into your routine once a week and see how your skin responds. Exfoliating acid toners don’t need to be used more than 3 times a week for most people. 

For those pesky pimples that pop up regularly in isolated areas, using a face wash or toner across your entire face might not be necessary, especially if you have combination skin. In that case, you may want to try Software’s AHA/BHA Pimple Patches, which work to target the spots directly. 

Are there any side effects of using AHAs?

As with a lot of skincare products, there is an element of trial and error because there can be some side effects. You may find that AHAs make your skin feel stingy, tight, red, or even develop blisters if continually used whilst irritation occurs. 

It’s important to never use AHAs on broken, inflamed skin, or sore, uncomfortable acne as this can exacerbate the problem. 

How to incorporate AHAs into your skincare routine

So, you want to start seeing the benefits of an AHA, how do you go about incorporating it into your existing routine? 

First things first, you need to start slowly — and we mean really slowly. Begin using it just once a week and monitor how your skin feels after using it.

If don't experience irritation (no, burning doesn’t mean the product “is working”), you can start using it twice a week and then 3 times a week if you feel like you could benefit from it. 

It’s not recommended to use an AHA more than 3 times a week, simply because you don’t need to. Don’t be tempted to start using a bunch of new products all at once. Incorporate your chosen AHA whilst using other products that you know your skin reacts well to.

Mistakes to avoid when using acids in your skincare

There are plenty of mistakes you can make when it comes to AHAs, but that doesn't mean they aren't worth using. You just need to understand the golden rule: avoid irritation at all costs.

Here are a few common mistakes: 

Overusing the product

The biggest mistake people make when it comes to using acids in their skincare is overdoing it and ruining their skin barrier.

The skin barrier is responsible for keeping the good stuff (moisture) in and the bad stuff (pollution) out. If that’s compromised by overzealous exfoliation, it can make your skin feel irritated, inflamed and even break out. 

Overdoing the application amount

You also want to make sure you’re not using too much of the product. You typically need a lot less than you think. Start small and gradually work your way up. And, remember to read the instructions on the packaging and stick to it! 

Not following up with yes, SPF

We’re going to keep telling you until you get sick of us! You need to be wearing sunscreen every day (yes, even when it’s winter or cloudy out), particularly so if you’re using an AHA. 

When you're putting in the effort to fade dark spots with AHAs, sunscreen is an important part of the routine as it helps prevent the further development of pigmentation.

Cocktailing it with active ingredients

Skin experts will often tell us that the best skin comes from the simplest of routines. That means often not cocktailing a bunch of different ingredients together

Products are formulated to incorporate many ingredients at once that work together in synergy and won’t counteract each other. Don’t be tempted to try 12 different products at a time with strong ingredients. 

Choose your fighter and give it at least 3 months to see a difference. 

Using the wrong acid for your skin type

Leaving perhaps the hardest for last, making sure you’re using the right acid for your skin type is imperative. After all, you don’t want to go in with the most potent acid if you have super sensitive skin. It’s a recipe for disaster (and a whole lot of skin irritation). 

Here’s our simple guide: 

AHAs are used for acne-prone skin and those who feel their skin can withstand potent ingredients. 

BHAs are primarily used for those with oily skin. 

PHAs (we didn’t get on to these but they’re worth reading up on) are another category of acids that are wonderful for sensitive skin types. 

Trust us, when done correctly, AHAs will change your skincare game for the better so it's worth noting these key points.

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