N-Hydroxysuccinimide Best Humectant Hydration N-Hydroxysuccinimide at a glance Used to soften and condition skin Is a reagent, meaning it triggers a reaction that creates a new substance Can trigger the production of peptides and polymers Is a white solid in its raw form N-Hydroxysuccinimide description N-hydroxysuccinimide is a synthetic ingredient used in cosmetics as an ester to soften and condition skin. It’s also a reagent, a substance used to trigger a reaction that leads to a new substance, such as peptides and polymers. Not surprisingly, it is most often found in glycerin-based blends that contain peptides. The recommended range for these blends is typically 2–5%. In its raw form, it is a white solid. N-hydroxysuccinimide has no known safety concerns.