The result is millions of tiny bubbles. Obviously, the air bubbles are using the surfactants that should be removing dirt and oil. We have all seen shampoo advertisements showing happy, beautiful people taking showers with their heads heaped high with mounds of lather. These images have taught the public to associate lather with cleansing ability. The truth is, lots of foamy lather only means too much shampoo was used.
Excess foam equals waste.
Sebum and other oils quickly destroy foam. Ideally, the head should have just enough lather to lubricate the scalp and hair. This will help your fingers massage the shampoo more effectively into the hair. Fragrances and foaming qualities are not good ways to evaluate shampoos. Examine the hair's condition after several uses.