Review (3/5): Yes it lightens, but your overall outcome may vary
Bought the volume 40 bottle to use on my beard, which naturally has a mix of white and dark brown hair. I wanted this product to whiten the dark brown hair to match the other already white hair. Easy enough to mix & apply a thick coating to the beard. I left it on a bit longer than the recommended time. The hair became a mix of white and a patchy, gross yellow color. Oddly enough, there was more yellow areas than I had dark brown hair, so I'm not sure what the lightener was doing to the already white hair.
Does it lighten, yes.
Does it lighten consistently across the hair? No.
Will it lighten to white? Doesn't seem so.
Would I buy this again? Probably not.