This gray root-touch-up can double as a way to camouflage hair loss or thinning. It seamlessly conceals patches, with 95 percent of users agreeing it blended well with their hair color. “This works great at covering my thinning spots of hair. Just dab a little on the scalp and blend with the applicator sponge. Very easy to use and a perfect solution to visible scalp,” writes one reviewer.