Quinoa Oil- Derived from quinoa grain, it may have disinfectant properties .
Quaternium-15- Formaldehyde-releasing preservative used in cosmetics. It can be a skin sensitizer.
Quaternium-18 Hectorite- Used as a suspending agent and also has emulsifying properties.
Quenching- A process that occurs when the action of one compound in an essential oil is suppressed by another compound, thereby making the oil safer for use.
Quercetin- A bioflavonoid ingredient from plants. Quercetin occurs naturally in red wine, tea, onions, kale, tomatoes, berries, and many other fruits and vegetables.
Quillaja Extract- Extract of the Chilean soap bark tree. It contains a good amount of saponins.
Quince Seed- Used as a thickening agent in cosmetics, but also has skin-constricting properties.