Undecylenic Acid ●
TL;DR. This ingredient is used mainly as an antimicrobial and deodorizing agent, with particular value in formulas where control of yeast or odor-associated microbes matters. It can also support preservation systems and contribute mild fatty-acid conditioning.
What does Undecylenic Acid do in a cosmetic formula?
This ingredient is used mainly as an antimicrobial and deodorizing agent, with particular value in formulas where control of yeast or odor-associated microbes matters. It can also support preservation systems and contribute mild fatty-acid conditioning.
Is Undecylenic Acid clean?
From a clean-beauty perspective, it is generally well accepted and is not a common restricted-list concern. At higher active levels it can be irritating, so comfort depends on dose, formula pH, and whether it is used in leave-on or rinse-off products.
Is Undecylenic Acid sustainable?
This material is commonly made from castor oil, a renewable plant feedstock, through fatty-acid processing. It is expected to biodegrade more readily than many synthetic antimicrobial materials and has limited persistence concerns.
Is Undecylenic Acid COSMOS-approved?
It is generally compatible with COSMOS-natural and COSMOS-organic frameworks when sourced and processed according to the standard’s allowed chemistry. Its renewable origin, simple fatty-acid structure, and biodegradability fit Green Chemistry expectations well.
How does Undecylenic Acid work chemically?
The molecule is an 11-carbon unsaturated fatty acid with a terminal double bond and a carboxylic acid group, which gives it both lipid affinity and pH-dependent antimicrobial activity. It is most active in its protonated acid form, so performance is better in mildly acidic systems, while salts are more water-dispersible but can behave differently in preservation and skin-feel.
Last updated 2026-05-15