Understanding acids

Understanding acids

Acids are fundamental to modern skincare, providing exfoliation, acne treatment, hydration, and anti-aging benefits. In chemical peels, they range from gentle, superficial exfoliation to deep, professional resurfacing.

Here is an A-Z guide to the most common acids used in skincare and chemical peels.

A

• Alpha Hydroxy Acids (AHAs): A group of water-soluble acids derived from sugary fruits. They exfoliate the surface of the skin to improve texture, boost collagen, and reduce fine lines. Common examples include Glycolic and Lactic Acid.

• Alpha Lipoic Acid: A powerful antioxidant that helps improve skin smoothness and reduces inflammation.

• Amino Acids: The building blocks of proteins like collagen and elastin, used in skincare to strengthen and repair the skin barrier.

• Ascorbic Acid (L-Ascorbic Acid): A potent form of Vitamin C used to brighten skin, fade dark spots, and protect against free radical damage.

• Azelaic Acid: A dicarboxylic acid that reduces inflammation, kills bacteria, and treats rosacea and acne. It is also effective at inhibiting melanin, making it great for pigmentation.

B

• Beta Hydroxy Acid (BHA/Salicylic Acid): Oil-soluble acids that penetrate deep into the pores to remove sebum and dead skin cells, making them ideal for acne-prone skin.

• Benzoic Acid: Used primarily as a preservative in skincare, but can have exfoliating properties in certain formulations.

C

• Citric Acid: An AHA derived from citrus fruits. It is used to exfoliate the surface of the skin, balance pH levels, and neutralise free radicals.

F

• Ferulic Acid: A plant-based antioxidant that boosts the stability and efficacy of Vitamins C and E, protecting the skin against sun damage.

G

• Glycolic Acid: A popular AHA derived from sugar cane. Because of its small molecular size, it penetrates deeply, making it a very effective ingredient for anti-aging and resurfacing peels.

H

• Hyaluronic Acid: Unlike others, this is a humectant, not an exfoliator. It holds up to 1,000 times its weight in water, providing intense hydration and plumping the skin.

K

• Kojic Acid: Derived from fungi, this acid is mainly used to brighten the skin, treat melasma, and fade acne scars by inhibiting melanin production.

L

• Lactic Acid: An AHA derived from milk or fermented sugar. It is gentler than glycolic acid, offering exfoliation while simultaneously hydrating the skin.

• Linoleic Acid: A fatty acid that helps maintain the skin's barrier and is beneficial for calming acne-prone skin.

M

• Mandelic Acid: An AHA derived from bitter almonds. It has a larger molecule size, making it gentle and ideal for sensitive or dark skin tones.

• Malic Acid: An AHA derived from apples. It is often used in combination with other acids to improve skin texture and tone.

P

• Phenol (Carbolic Acid): A deep peeling agent used by professionals for extreme resurfacing to treat deep wrinkles and severe sun damage.

• Pyruvic Acid: An alpha-keto acid that converts to lactic acid on the skin. It acts as a powerful exfoliating agent with a lower risk of scarring, often used in concentrations of 40-70%.

• Polyhydroxy Acids (PHAs): Next-generation AHAs (like Gluconolactone) that offer exfoliation for sensitive skin without causing irritation.

R

• Retinoic Acid (Tretinoin): A powerful derivative of Vitamin A (retinoid) that increases cell turnover, boosts collagen, and treats acne/aging.

S

• Salicylic Acid (BHA): The most common BHA, renowned for its ability to clean out pores, reduce blackheads, and calm acne breakouts.

T

• Tartaric Acid: An AHA found in grapes and wine, often used to stabilise the pH of other products and provide mild exfoliation.

• Trichloroacetic Acid (TCA): A, medium-depth peel acid used for reducing skin pigmentation, wrinkles, and acne scars.

Summary of Use

• For Acne: Salicylic, Azelaic, Mandelic, Glycolic

• For Aging/Wrinkles: Glycolic, Lactic, Ascorbic, Ferulic

• For Pigmentation: Kojic, Azelaic, Glycolic, Lactic

• For Hydration: Hyaluronic, Lactic