Roy Teeluck Concentré de Collagène Serum
Roy Teeluck Concentré de Collagène Serum is like the hair equivalent of a facial filler: It infuses strands with collagen for youthful plumpness, which makes hair look fuller. To get an instant boost, massage a few drops of the serum into freshly washed and towel-dried roots, then blow-dry for the big reveal. And we do mean big.
To buy: $55, royteeluck.com.