Ingredient Dictionary


quaternium ammonium compounds

A wide range of ingredients, called “quats” for short, that share a unique molecular structure that... Read More »

Categories: Miscellaneous



Formaldehyde-releasing preservative used in cosmetics. It can be a skin sensitizer, as can all... Read More »

Categories: Irritants, Preservatives


quaternium-18 hectorite

Used as a suspending agent and also has emulsifying properties. Read More »

Categories: Thickeners/Emulsifiers



A bioflavonoid ingredient from plants. Quercetin occurs naturally in red wine, tea, onions, kale, tomatoes, berries, and many other fruits and vegetables... Read More »

Categories: Plant Extracts, Antioxidants



See oak root extract

Categories: Antibacterial/Anti-Acne, Irritants, Plant Extracts


Quercus infectoria extract

See oak root extract

Categories: Irritants, Plant Extracts, Antibacterial/Anti-Acne


quillaja extract

Extract of the Chilean soap bark tree. It contains a good amount of saponins, which have cleansing,... Read More »

Categories: Antibacterial/Anti-Acne, Plant Extracts


quince seed

Used as a thickening agent in cosmetics, but also has skin-constricting properties (Source:... Read More »

Categories: Plant Extracts, Thickeners/Emulsifiers, Irritants


quinoa oil

Derived from quinoa grain, it may have antifungal properties (Source: Journal of Agricultural Food... Read More »

Categories: Emollients, Plant Extracts

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Paula Begoun is the best-selling author of 20 books on skin care and makeup. She is known worldwide as the Cosmetics Cop and creator of Paula's Choice. Paula's expertise has led to hundreds of appearances on national and international television including:

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