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

Results Per Page:
Page 1 of 1

About the Experts

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:

View Media Highlights

The Paula's Choice Research Team is dedicated to busting beauty myths and helping you solve your skincare frustrations with research-supported expert advice—so you'll have the facts you need to take the best possible care of your skin.

Skip to Top of Page

Free Email Sign-Up

- (Less Frequent)
- Expert Advice Newsletter (twice a month)
- New reviews on Beautypedia (twice a month)

Birthday (Fill out to receive a birthday surprise)



Paula’s Choice Auto Delivery is a quick and convenient way to make sure you never run out of your favorite products again. Just select the products you can’t live without, choose how often you’d like them delivered and we’ll take care of the rest.

Get 10% off your first order when you sign up today.