Unfortunately, it's only the Canadian version of PrepH that works. The US version lacks the active ingredient, bio-dyne, which is an oxyen-bearing yeast derivative.

Apparently Conan O'Brien and other stars discovered that it reduced the bags and puffiness under their eyes before show time. Word got around, and soon the FDA came after the PrepH company demanding they cough up the studies to prove these claims of skin tightening. Well, the PrepH company never made those claims, it was just word of mouth from people using it. So ... the PrepH company removed bio-dyne from the US product to avoid being charged by the FDA. However, bio-dyne is still in the Canadian version.

You can read more about it here .. Only In Canada.

Doreen

p.s. - I keep a small tube in the medicine chest and yes, it does temporarily reduce puffy bags under the eyes, and also reduces redness of the occasional zit, as a spot treatment.