Does a shampoo clean better if it foams or lathers more?

Lots more lather doesn’t make much difference to a shampoo’s effectiveness. The lather is mostly soapy air bubbles, which have little to do with how well the shampoo traps dirt and oil. However, chemicals are sometimes added to shampoo so that they produce more lather – people tend to associate more lather with a more effective clean, so companies use this trick to encourage customers to buy their brand.