AHA, BHA, PHA or Enzymes? Choosing the Right Exfoliant (and When to Use It)

09 October 2026 · MakeYourSkin Team

Illustration of four exfoliant bottles labelled AHA, BHA, PHA and enzymes with a pineapple and papaya slice — MakeYourSkin Journal

Exfoliating is like tidying a room. Do it gently and regularly and everything looks fresher. Do it with a leaf blower every day and, well, things get knocked over. Chemical exfoliants let you choose your "cleaning tool", and there are four main families. Let's meet them.

AHAs: the surface polishers

Alpha hydroxy acids are water-soluble and work on the skin's surface, loosening the "glue" between dead cells so they shed more evenly.

  • Glycolic Acid: the smallest AHA and the most intense. Best for resilient, sun-tired skin.
  • Lactic Acid: a little gentler, and it hydrates as well. A great all-rounder.
  • Mandelic Acid: a larger molecule that penetrates slowly. Popular for sensitive or darker skin tones.

The rules: the US FDA notes AHAs can increase sun sensitivity, and the CIR safety panel considers them safe at 10% or less with a final pH of 3.5 or higher. They also recommend sunscreen during use and for a week afterwards (FDA).

BHA: the pore diver

Salicylic Acid is the star here. Unlike AHAs, it's oil-soluble, so it can travel into oily pores and help clear them. That's why it's the classic choice for blackheads and blemish-prone skin (Arif, Clinical, Cosmetic and Investigational Dermatology). The FDA advises sun protection with BHAs too (FDA).

The rules: in the EU, salicylic acid is allowed up to 3% in rinse-off hair products and 2% in other products, with a lower 0.5% cap in some product types such as body lotions (UK SAG-CS opinion). Check the dictionary entry and your market's rules before you finalise a formula.

PHAs: the gentle giants

Polyhydroxy acids like Gluconolactone and Lactobionic Acid are bigger molecules, so they penetrate slowly. A 2023 study linked gluconolactone's large size to less redness and flaking (note: the authors had ties to the product's maker) (Pharmaceuticals, 2023). PHAs are also humectants, so skin tends to feel comfortable afterwards.

Enzymes: the fruit-powered option

Papain (from papaya) and Bromelain (from pineapple) are proteolytic enzymes. They break down the proteins holding dead cells together rather than relying on acidity. A 2025 study describes them as a gentler alternative to scrubs and acids (Applied Sciences, 2025). They're lovely in powder cleansers and wash-off masks. Enzymes are sensitive to heat and storage, so follow the supplier's handling notes.

Which one, when?

  • Dull, uneven, sun-tired skin: glycolic or lactic acid.
  • Blackheads and oily skin: salicylic acid.
  • Sensitive, reactive or dry skin: PHAs, mandelic acid or enzymes.
  • Exfoliation beginner: start with a PHA or a lactic acid toner two or three times a week.
  • Body (rough elbows, bumpy arms): lactic acid. More on body care in Monday's post.

When to skip

  • On broken, sunburned or freshly waxed skin.
  • On the same night you introduce a retinoid. Alternate nights instead.
  • If you're already using a prescription exfoliating treatment, unless your dermatologist says otherwise.

Formulator's checklist

  • pH is everything with acids. Revisit our pH guide and measure every batch.
  • Patch test, and add a "use sunscreen" note to your label.
  • Pair with soothers like Allantoin or Panthenol.

Browse the full range in Acids & Chemical Exfoliants, and gentle partners in Soothing & Anti-Irritant Agents.