Mandelic Acid Vs Lactic Acid


These kinds of posts have become so popular over my years running this site that I’ve actually dedicated a whole category to acids on my homepage. The reason (I think) for this rise in queries is because, this particular trend requires you to know more about your skin before you decide which one is right for you. Although these ingredient have been used for years in skincare, brands like The Ordinary isolated them as the ‘useful’ components of the product. This means that the previous deciding factors of your skins fate; dry, oily and sensitive, no longer suffice to determine which product you should buy because technically anyone can use anything at the right concentration and with the correct other products to support it. You, as a savvy consumer, just have to know more about the basic science of what these ingredients do in order to buy the best thing for you. Hence, these posts are essential to getting better skin.

With this in mind I have brought you another one, this time featuring a newer acid. Well, technically it’s not new but it hasn’t been talked about very much before: mandelic acid.

What is mandelic acid?

First and foremost it is an Alpha Hydroxy Acid, which if you remember from this post, means it is water soluble. So, it only works on the surface of skin. Other AHA’s include lactic and glycolic acid.

All the AHAs have slightly different potency/side effect profiles, Glycolic acid is the most potent and can give the most dramatic results. This is due to the fact that it’s the smallest AHA hence, it gets through skin most easily. It also means that in a 5% glycolic acid product, you’ll have more AHA molecules than in any other 5% product of any other AHA.

Lactic acid is larger than glycolic and generally causes less side effects, the less molecules penetrating the skin the less damage it will do. Lastly, mandelic acid – it’s actually the largest of the three and it’s the AHA most often recommended for PIH-prone skin. The basic theory with acids is therefore, the bigger the particle size the more gentle it is on your skin. Therefore, mandelic acid is even more gentle than lactic acid.

What benefits does mandelic acid have on the skin?

Wrinkles and fine lines
As with all exfoliating acids mandelic acid works to accelerate cell turnover by dissolving the tiny bonds that hold skin cells together, helping to remove dead skin on the surface that can lead to dull complexions, as well as fine lines. It also strengthens collagen, one of the building blocks of the skin’s support network that gives it youthful firmness.

Hyperpigmentation and discolouration
Malesma is a common skin condition in which light to dark brown or greyish pigmentation develops on the face. Mandelic acid has been shown to reduce melasma by as much as 50% in four weeks, resulting in a more evenly coloured complexion.

Mandelic acid’s antibacterial properties are extremely helpful in treating acne. It also helps to regulate sebum production and in turn decrease the occurrence of breakouts. Mandelic acid has even been shown to benefit those who suffer from cystic acne. 

Why is it different to lactic acid?

I didn’t go in too deeply about the function of lactic acid this time because I am sure you’re well acquainted with it by now. But the real question still remains, how do I choose between lactic acid and mandelic acid if they have basically the same function in skin?

Simply put, the reason you would buy mandelic acid over lactic is if you have very sensitive skin. That’s really its biggest benefit in this comparison, it really is more gentle than lactic acid. So, if you have always confused as to why skincare ‘experts’ suggest using lactic acid for sensitive skin because you’ve always been irritated by it, then give mandelic acid a go.

Similarly to lactic acid, the best way to deliver it to the skin is in small amounts, using light patting motions that press the product into your skin. After which you can add your hydrating factors.

Product recommendations

Medik8 Pore Cleanse Gel Intense, £21

DCL Multi-Action Penta Peel, £40.50

Dr Dennis Gross Alpha Beta Pore Perfecting Cleansing Gel, £17

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