Podcast: Episode 36, which exfoliating acid for my skin?

Listen to the audio episode to find out which exfoliating acid to use for your skin!

• Available on: Episode 35, AHAs, exfoliating acids?
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Which acids for your skin?

Here is a guide to recommended acids based on skin types .

glycolic acid

It is the smallest of the AHAs, and therefore the most effective, but on the other hand, it is the most potentially irritating. As always when I describe the ingredients, keep in mind that its effectiveness and irritant potential depend above all on its concentration and the rest of the formula. It is probably the most studied of the AHAs too, it is very well known, it is obtained from sugar cane.

If your skin tolerates it and your skin barrier is not damaged, it is recommended for you.

Oily, combination and normal skin types will be more likely to like it than dry skin types.
It is effective in improving the texture of the skin (less micro-reliefs, age spots and faded acne scars).

lactic acid

It is also a very well known AHA, it is obtained from lactose, which is the sugar in milk.
It is a little larger than glycolic acid so it penetrates very slightly less than the latter. It is naturally present in the skin and has moisturizing properties.
This is why it is generally recommended for normal to dry skin.

It is effective in improving the appearance of skin texture and in moisturizing.

malic acid

It is a larger than glycolic and lactic acids because it contains two carboxyl groups of carboxylic acids. As a result, it is less active.

If you count the position of the hydroxyl group relative to one carboxyl group or the other, malic acid is an AHA and a BHA. It is obtained from certain fruits, in particular apples. It is generally recommended for sensitive skin, as it is less irritating than other AHAs.

It is effective in improving the appearance of skin texture.

mandelic acid

It is a big AHA, obtained from almond. Its large size greatly reduces its risk of irritation, but also its effectiveness.

It is also known to have antibacterial and anti-inflammatory properties, making it a prime candidate for acne-prone skin .

Its association with other acids can be a good idea to support its exfoliating activity.

citric acid

It is the largest of the AHAs, which makes it less effective for exfoliation. It is also a BHA.

It is very often used in the cosmetics industry to adjust the pH of cosmetics. At the percentages used, it is not very effective in exfoliating.

salicylic acid

It is an alpha-hydroxy acid obtained from willow bark, it has an antibacterial action and is able to decrease the production of sebum . It is therefore perfect for acne-prone skin.

Some studies have also shown that it is photo-protective and anti-inflammatory, thus helping the skin to protect itself from UV rays . Be careful though, its protection does not equal sun protection, and it therefore does not replace it in your routine.

Salicylic acid is often incorrectly referred to as a BHA in the cosmetics industry. If you're looking for a product that contains it, look for BHA on the skincare product, and there's a good chance it's in the product. I quickly go into detail on why it's not a BHA when its hydroxyl group is on the beta carbon, 2 carbons away from the carboxyl group. This is because the hydroxyl group is on an aromatic ring, which makes the whole thing become a phenol group (aromatic ring + OH) and it no longer has the behavior of a classic BHA, for a question of behavior acid.

The rest of the formula

Although this ingredient information is important for your understanding of how they work. The rest of the formula is essential to support their effect and avoid the risk of irritation.

It is not absolutely essential to memorize the effects of each AHA by heart because the recommendations of the cosmetics will be your best allies to guide you, because they take into account the percentages and the whole of the formula.

In conclusion, exfoliants help the skin to eliminate dead cells on its surface, leaving the skin more homogeneous (reduced micro-reliefs, faded spots, more luminous skin).

Alpha-hydroxy acids, also called AHAs or fruit acids, are active ingredients that reduce the adhesion of dead cells to the surface of the skin to facilitate their elimination. Glycolic acid is the most powerful of them. Lactic acid is recommended for dry skin because it improves hydration. Malic acid is recommended for sensitive skin because it is less irritating, but less active. Mandelic acid and salicylic acid (note that the latter is not an AHA) are recommended for acne-prone skin thanks to their anti-bacterial properties. Consider trying the product on a small area of ​​your skin before applying it all over your face or body, and put on sunscreen the next few days.