Glyceryl undecylenate is an ester created by joining glycerin – a naturally occurring humectant – with undecylenic acid, a fatty acid traditionally sourced from castor oil. The resulting molecule carries a dual nature: the glycerin portion attracts and binds water, helping to support skin hydration, while the undecylenic acid side confers broad-spectrum antimicrobial activity. Because both building blocks are plant-derived, formulators often favor this ingredient when they want to keep a “naturally inspired” label while still achieving reliable preservation.

In skin-care and personal-care products, glyceryl undecylenate is typically used at low levels – about 0.3 to 1 percent of a formula – where it helps suppress the growth of bacteria, yeast, and mold. It is frequently paired with other mild preservative boosters, such as caprylyl glycol or glyceryl caprylate, to create a complete hurdle system that meets modern safety standards without resorting to older, more controversial preservatives. Beyond its protective role, the ester’s small molecular size allows it to soften the skin’s surface, improving glide and after-feel in emulsions, gels, and wipes. Regulatory bodies in Europe, the United States, and Japan list glyceryl undecylenate as safe for use in rinse-off and leave-on products when formulated within recommended limits, and it is well-tolerated even by sensitive skin because it is non-ionic and free of parabens, formaldehyde donors, and isothiazolinones. For brands seeking a gentle, multifunctional ingredient that aligns with clean-beauty expectations, glyceryl undecylenate offers an elegant way to boost preservation while adding a touch of emolliency in one easy step.