In shampoo ads, hair always looks like a shiny, smooth surface. But for physicists peering into microscopes, the hair surface looks much more rugged, as it is made of saw-tooth, ratchet-like scales. In a new theoretical study published in EPJ E, Matthias Radtke and Roland Netz have demonstrated that massaging hair can help to apply drug treatment – encapsulated in nanoparticles trapped in the channels formed around individual hairs – to the hair roots. This is because the oscillatory movement of the massaging directs the way these particles are transported.