All about acids – AHA’s & BHA’s

The Ordinary do a good range of acids for at home use.

Peel season is fast approaching as the winter months start to draw in, less sunlight exposure to our skin makes it the perfect time for the more invasive skin treatments that can cause photo sensitivity. Time to get out the retinols, hydroxy acids and book in for skin peels with your aesthetician.  If you are planning on getting married in the summer months then now is also the perfect time to start using these products whether at home or with a course of professional treatments.

If you are looking at acids for the first time then it can be quite confusing with all the different types of products on the market and not only are there different types of acids but also various strengths and formulations. Here is a brief rundown without going into too much detail to help you navigate your way through and choose the best acid for you.

Why use an acid? Acids exfoliate the skin and are actually much more gentle on the skin than they sound, in fact they are less damaging than gritty exfoliators because you are less likely to press too hard or scratch your skin. Acids exfoliate the dead skin cells by gently unglueing them from the skin which reveals the newer fresh skin cells underneath, this gives dull dry skin a healthy brighter glow and can help fade discoloration. Some acids work by cleaning out the sebaceous glands which can help minimize blackheads and breakouts. Regular use of acids helps to improve the skins overall texture achieving flawless skin and a more smoother finish when applying your make-up. As we age our skin cells don’t turn over as frequently as they use to so by stimulating this process with acids you can help to soften fine lines and wrinkles. Another advantage to using acids is that your skin care products (particularly retinols, antioxidants and peptides) can penetrate deeper because they are not being absorbed by the top dead layer of skin. By reaching further down into the skin they become more potent as they are able to work in the more active layers giving you better results.

What are the different types of acids?

Alpha hydroxy acids (AHA) and beta hydroxy acids (BHA) are the main two different types, the difference between them is that AHA’s are water soluble and work more on the surface of the skin loosening up the dead skin cells and BHA’s are oil soluble and work much deeper within the pore to help unplug them. The different acids are also different molecule sizes, larger molecules such an mandelic acid will penetrate the skin more slowly and work more on the surface which means they don’t penetrate as deep therefore less likely to cause any irritation and more gentle for sensitive skin. Smaller molecules such as glycolic acid can penetrate the skin much deeper and quicker making them more likely to be irritating.

Which acids are AHA’s? 

Glycolic Acid is an AHA and is derived from sugar cane. it’s the smallest molecule which penetrates the skin much deeper than the other AHA’s. It’s considered the holy grail of exfoliants, great for skin discoloration, dry patches and signs of ageing such as fine lines and wrinkles due to its ability to stimulate collagen and elastin production. Acne prone skin can also benefit due to the lifting off of dead skin cells, by keeping the pores unclogged you can help reduce acne.

Lactic Acid is an AHA derived from sour milk (the byproduct of bacteria consuming the lactose in the milk) it’s a larger molecule than glycolic acid making it less irritating to the skin, it works mainly by exfoliating the surface layers of the skin making it good for skin texture and fine lines. Lactic acid can also have a moisturising effect and might be a better option for more frequent use or first time users of acids because it’s benefits are similar to glycolic but due to its larger molecule size it’s less likely to irritate.

Mandelic Acid is an AHA derived from bitter almonds, it’s the largest molecule penetrating the skin at a much slower rate therefore it’s the most gentle on the skin, good for all skin types especially sensitive as it works more on the surface. Mandelic acid is a good skin brightener and recommended for hyperpigmentation especially with darker skin tones.

Malic Acid is an AHA found in foods and is also produced naturally in the body, although malic acid is not as widely used as the other acids it’s effects on the skin are the same as the other AHA’s but it has the added advantage of being considered an antioxidant and humectant and is less irritating to the skin.

PHA Acids (Polyhydroxy acids) are the next generations of AHA’s, their large molecular size means they work more on the surface of the skin making them a gentle exfoliant suitable for all skin types, they are also humectants so if you are sensitive to other acids then PHA’s might be a better option.

Which acids are BHA’s?

Salicylic acid is a BHA and is derived from willow bark, beneficial for oily acne prone skin because it’s oil soluble which allows it to work much deeper within the pore dissolving the keratin plugs which leads to blackheads and spots.

What are the different formulas?

The different acids can be found in nearly all types of skin care such as cleanser, toners, serums, face masks and for more stronger treatments you can have professional salon peels and medical grade treatments performed by dermatologists (some of these tend to have down time though with redness and skin peeling). Popular affordable high street brands The Ordinary and Pixi both have a good range of different acids but most high street brands these days have acids within their range.

Most acids are best used at night time, start off using them in rotation such as three or four nights on and three or four nights off till your skin gets used to them. Start off with the lowest percentage and then increase as your skin feel less sensitive.

When using acids it’s important to use sunblock as part of your morning skin care routine, by removing the surface layer of dead skin cells you increase your skins sensitivity to the suns UV damaging rays. Click here if you want to read more about mineral and chemical sunscreens. You can also view the professional glycolic peels that I do by clicking here.


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