There are good reasons for a double shampoo – if you can avoid waste

An Italian town has banned the practice during a heatwave, but if done right it benefits hair and scalp

Global consumption of water is growing twice as fast as the world's population and droughts are affecting swathes of the planet. So it was no surprise that this week the mayor of an Italian town in Emilia-Romagna, which is experiencing a severe heatwave, banned hairdressers from shampooing their customers' hair twice, saying it would save thousands of litres of water a day.

As we all attempt to reduce waste, that additional shampoo at home or in the salon can seem like overkill. So is what is known in the trade as double cleansing" really necessary? No, but every hairdresser and trichologist is seemingly in agreement that the second shampoo has distinct benefits to scalp and hair, regardless of skin and hair type.