Enzymes for gray hair?

Over the past year, reports have surfaced indicating that gray hair may be caused by an accumulation of hydrogen peroxide in hair shafts.  This appears to be a result caused by deficiencies in certain metabolic enzymes such as catalase, methionine sulfoxide reductase, and tyrosinase.

It didn't take long for some dietary supplement companies to take this information and provide a so-called "solution" to the problem. 

Some products have popped up espousing the use of catalase, an enzyme involved in the breakdown of hydrogen peroxide and other free radicals, in an oral supplement to reverse the graying of hair.  Playing on the vanity of those who can't accept that they are getting older (and showing it) is a sure-fire way to make a buck these days.

Unfortunately, these products don't work because catalase is an unstable enzyme easily degraded by stomach conditions.  Even if it did survive the gut, there is no way to direct the catalase specifically to hair follicles - it would simply be distributed throughout the circulation and then removed by the body's defenses.

I am a guy in his fifties whose hair is full of gray.  I actually get a lot of compliments on my salt-and-pepper look, and I know I wouldn't be fooling anyone if my hair suddenly became dark again.