Hydroxyethylpiperazine Ethane Sulfonic Acid (HEPES, also known under the trade name PromaCare-HEPES) is an organosulfur acid with an AHA-like structure and action. Although it is not a classic hydroxy acid, thanks to structural similarities and faintly acidic properties, it also acts as an exfoliating agent like AHAs and BHAs, breaking bonds between keratinocytes, softening keratin, and eliminating old, dull, and dead cells from the skin surface.
Gently removing pigmented cells (keratinocytes containing melanin) from the epidermal layer, Hydroxyethylpiperazine Ethane Sulfonic Acid leaves a significant skin-whitening effect, while smoothing the surface, softening texture, and unifying the tone. In addition, it boosts the adsorption of other active ingredients and acts as a buffering agent keeping constant the pH state of the entire formula for a long time.
Thanks to stabilizing properties, Hydroxyethylpiperazine Ethane Sulfonic Acid protects active ingredients and skin from UV and visible light exposure, adsorbing and partially reflecting harmful radiation. It has good membrane impermeability and practically doesn't penetrate through the epidermis and has a very narrow action on biochemical processes in the deeper layers of the skin.
HEPES has good solubility in water, heat resistance, membrane impermeability, and higher stability against oxidation-reduction reactions and UV, which makes it a good candidate for exfoliating, sun-care, and skin-lightening formulations.