The largest group, accounting for around 65%, they have negatively charged heads. Considered the high-foaming powerhouse surfactants, these include the soaps, the sulfates (e.g. sodium lauryl sulfate), as well as gentler alternatives like sodium lauroyl sarcosinate. If you see a surfactant beginning with ‘sodium’ and ending with the ‘-ate’ suffix, it’s safe to say it’s anionic.
Making up only around 3.5% of the surfactant market, these chemicals aren’t typically used for cleansing, but instead are known for their antimicrobial properties. Common cationic surfactants include cetrimonium bromide and benzalkonium chloride.
At around 28% of the market, non-ionic surfactants make up the second largest group. They don’t generally make good cleansers, being very low-foaming and mild, but find their way into many products as emulsifiers, ingredients that hold the oil and water parts together in a cream, the same way an egg helps hold together the ingredients in a cake. Some common non-ionic surfactants include glyceryl monostearate, PEG-100 stearate, and the ceteths, laureths, and ceteareths.
Another relatively small group (3.5%), these surfactants have large heads with both a positive and negative charge. They are very mild on the skin and eyes, and are often used as secondary surfactants, paired with a more powerful anionic surfactant. An amphoteric surfactant used in a lot of soap-free cleansers is cocamidopropyl betaine.