Ingredient dictionary

Hydroxyethylpiperazine Ethane Sulfonic Acid

Also listed as: HEPES

A synthetic buffer that helps keep a product's pH steady, so the formula stays stable and consistent over time. It is on the label of 10 products in our library. Checked against our library November 6, 2026.

What Hydroxyethylpiperazine Ethane Sulfonic Acid does

Keeps product pH steady over time
Helps resist sudden shifts in acidity
Helps other ingredients stay stable

HEPES is a lab-made compound. It belongs to a group of synthetic buffers that chemists developed for laboratory work, where keeping a solution at a steady pH matters. It is not taken from plants or animals. Its structure carries both positive and negative charges, which helps it hold pH steady near neutral.

Formulators add it because pH affects how a product feels, how long it lasts and how well its other ingredients work. A buffer like this resists small shifts in acidity, so a formula stays closer to its intended balance. It usually has little scent and dissolves easily in water-based products. In creams and lotions, you rarely notice it at all.

Good for

Suits everyday moisturizers, body lotions, sunscreens and exfoliants, where a steady pH keeps the formula consistent for daily use.

Frequently asked questions

Is Hydroxyethylpiperazine Ethane Sulfonic Acid the same as HEPES?

Yes. HEPES is the short common name for this same compound. You may see either name on an ingredient list. Both describe a synthetic buffer that helps keep a formula's pH steady, so its job stays the same whichever name appears.

Is HEPES good for sensitive skin?

It is generally well tolerated, and it is used in many gentle formulas. Like any ingredient, it can still bother a few people. If your skin is easily irritated, patch test a new product first and ask a dermatologist if you have concerns.