If you aren't used to using vitamin C , which experts tout for brightening skin and fending off pollution, you might experience a slight tingle or even itchiness. Like acids, start small and slowly build up to regular daily use. Try Distillery Vitamin C-Shot Powder, £22 . Just add two dashes of the pure vitamin C to your daily moisturiser or SPF and apply as normal. "We like to use ingredients that are more concentrated," said Gina Ghura, Avon's executive director of future innovation, when we asked her about the trend for skincare microdosing. "It doesn’t have to be in a little capsule or serum. In fact, because this is so potent, you don’t have to use as much. Not only is a concentrated product typically more beneficial but it lasts longer, and it’s ecological, too."