Surfactants

The surfactants possess a hydrophilic part that attracts water and a lipophilic part that attracts oil, allowing them to capture fats and eliminate them during rinsing with water.

There are four main types of surfactants : anionic, cationic, non-ionic, and amphoteric.

This depends on the surfactants. It's true that some anionic surfactants, such as the sodium lauryl sulfate (SLS) and the ammonium lauryl sulfate (ALS), are often criticised for their irritating effects.

Yes, some products, particularly shampoos, are formulated without surfactants. These clean using alternative agents such as absorbent powders (clay, corn starch) that capture impurities and excess sebum, or emollients like vegetable oils and butters that dissolve dirt through lipid affinity.

This depends on the surfactants. Some, such as alkylpolyglucosides, are indeed biodegradable.