Sulfonic Acid (HEPES)
What is Sulfonic Acid (HEPES)?
Sulfonic acid (or HEPES) is a synthetically derived buffering agent. It's widely used in biological research to maintain the correct pH range in culture media used for growing cells during experiments. Its full chemical name is a bit of a mouthful—HydroxyEthylPiperazine Ethane Sulfonic acid—so everyone just abbreviates it to HEPES or plain old sulfonic acid!
HEPES also has a useful if less well-known role in skincare. Sulfonic acid is a mild chemical exfoliant − it activates natural enzymes in the skin to help break the bonds holding dead skin cells to the surface. By clearing these away and exposing fresh, newer skin cells at the surface, HEPES also aids the efficient absorption of other active ingredients. And its pH buffering capability also plays a role in skincare - it helps maintain a constant pH for the product to keep it at optimum activity over a longer period of time.