Rachel Jordan remembers why, if not exactly when, she decided to stop using shampoo. ‘It was around 10 years ago, I think. But I’m sure of one thing, I haven’t looked back since,’ she says. ‘I wasn’t a frequent hair-washer – only using shampoo once a week. But I did begin to notice how dry and dull my hair looked afterwards, and that it only became healthy and shiny again after a few days.’