Super common ingredient in all kinds of cleansing products: face and body washes, shampoos and foam baths.
Number one reason for its popularity has to do with bubbles. Everyone loves bubbles. And cocamidopropyl betaine is great at stabilizing them.
The other reason is that it’s mild and works very well combined with other cleansing agents and surfactants. The art of cleansing is usually to balance between properly cleansing but not over-cleansing and cocamidopropyl betaine is helpful in pulling off this balance right.
Oh, and one more nice thing: even though it’s synthetic it’s highly biodegradable.
More info on CAPB on Collins Beaty Pages.