AHA vs BHA; How To Choose The Right Type Of Exfoliation For You

All the cool kids are doing acid. From reducing the occurrence of breakouts by clearing gunk out of your pores to reducing dark spots and discolouration by promoting skin cell turnover, skincare acids are the solution to many common skincare woes. The most popular skincare acids—alpha-hydroxy acids (AHAs) and beta-hydroxy acid (BHA)—work to loosen and dissolve the bonds between dead skin cells, allowing them to be sloughed off and revealing the healthy skin underneath. 

You’ll also enjoy:
Feeling Sensitive? Mandelic Acid Is The Soft Girl Exfoliant That’s Gentle On All Skin Types
Regular Body Exfoliation Is The Crucial Step Your Skincare Routine Is Missing
Reveal Softer, Radiant Skin With These Exfoliating Toners For Every Skin Type

If the thought of putting acids on your face evokes imagery of Sex and the City’s Samantha Jones’ raw blistering face post-chemical peel, fear not. When used correctly, acids like AHAs and BHAs are perfectly safe. Here’s everything you need to know about using acids in skincare. 

What are the main types of skincare acids used in exfoliation?

The main types of skincare acids used are AHAs and BHA, however polyhydroxy acids (PHAs) are also growing in popularity. 

AHAs like lactic and glycolic acid are water-soluble and primarily work to exfoliate the surface layer of the skin, making them useful for treating fine lines, uneven skin texture, and dullness. Meanwhile, BHA — the main one being salicylic acid — is oil-soluble, allowing it to penetrate beneath the skin’s surface and clear out excess sebum (oil) from pores. BHA is particularly useful for treating oily and acne-prone skin.

Like AHAs, PHAs are water-soluble and work to slough off dead cells on the surface of the skin in a similar fashion. However, they have a higher molecular size, making PHAs well-suited to use on sensitive skin. PHAs include gluconolactone and galactose. 

The best acids for your skin

Whether you’re looking to brighten dull skin, improve hyperpigmentation, reduce wrinkles and fine lines, prevent breakouts, or simply look a little more ‘fresh’, there’s a skincare acid for you. 

1. For breakouts and clogged pores…try salicylic acid

One of the most popular ingredients for treating acne and excess sebum production, salicylic acid penetrates deep into the pores, dissolving the oil that clogs pores and loosening dead skin cells to exfoliate the skin. Plus, its anti-inflammatory properties make it ideal for use on preexisting acne, working to soothe and eliminate pimples. 

Acid family: beta-hydroxy acid (BHA)

2. For dullness, fine lines, and texture… try glycolic acid

Derived from sugar, glycolic acid is one of the most commonly used acids in skincare. Boasting the smallest molecule size of all AHAs, glycolic acid penetrates the skin the deepest, making it one of the fastest working, most effective acids on the market when it comes to exfoliation and thereby brightening the skin, evening out texture, reducing fine lines, and promoting skin cell turnover. However, its intense exfoliation also means it is liable to causing irritation in sensitive and reactive skin types.

Acid family: alpha-hydroxy acid (AHA)

3. For dullness and fine lines in dry skin… try lactic acid

Gentler than glycolic acid, lactic acid has the second smallest molecule size of all the AHAs. derived from fermented milk or sugar, lactic acid is a rare breed in that it both exfoliates and draws moisture to the skin, promoting increased hydration. Recommended for those with sensitive skin who can’t tolerate glycolic acid, lactic acid promotes hydration while evening out skin texture and reducing the appearance of fine lines. 

Acid family: alpha-hydroxy acid (AHA)

4. For sensitive skin… try gluconolactone 

For those unable to tolerate both lactic and glycolic acid, gluconolactone — a PHA — provides an ideal alternative. Like other PHAs, gluconolactone has a higher molecular size than AHAs, meaning it penetrates the skin less deeply and has a gentler effect, working to exfoliate the skin over time. It’s also a humectant, meaning it attracts water to the skin in a similar way to ingredients like hyaluronic acid and glycerin. While polyhydroxy acids like gluconolactone are typically teamed with AHAs and BHA, it’s possible to find products where PHAs are the star of the show, like the Medik8 Press & Glow daily exfoliating toner.

Acid family: polyhydroxy acid (AHA)

5. For hyperpigmentation and discolouration… try tranexamic acid

Something of a wildcard, tranexamic acid differs from the rest of the acids listed here. Neither an AHA nor a BHA or even a PHA, tranexamic acid is derived from the amino acid lysine and does not possess an exfoliating effect. Traditionally used orally in medicine for its blood-clotting properties to treat excessive blood loss from major trauma, surgery, postpartum bleeding, and heavy menstruation, tranexamic acid has also made its way into the skincare world. While its exact mechanism is unknown, tranexamic acid has shown to be beneficial in reducing existing pigmentation. Plus, it also works to prevent melanin synthesis caused by UV exposure by blocking the interaction between keratinocytes (skin cells) and melanocytes (melanin-producing cells). Tranexamic acid plays well with other skin brightening ingredients like retinol, vitamin C, and kojic acid.

Acid family: amino acid


Words by Esmé Duggan