For decades, hair washing has followed one unspoken rule: shampoo first, conditioner second. The order is so ingrained in the family line that most people rarely question if this is the only way to wash hair.
Now, a growing number of beauty enthusiasts are doing the opposite.
The latest haircare trend, known as the "shampoo sandwich", flips the traditional routine on its head by asking people to condition their hair before reaching for the shampoo.
