Consumers of sushi know wasabi, or at least think they do...  Truth is, most so called wasabi isn't, and the majority of products claiming to contain wasabi don't. 

What typically passes for "wasabi"  is a mixture of horseradish, food coloring, mustard, cornstarch and sadly, is a mere shadow of the real deal. 

REAL WASABI is one of the rarest and most expensive crops in the world and is extremely difficult to grow.

Maybe you are interested in learning about where organic wasabi grows and how it serves up such unique thrills to our taste buds, or perhaps you've heard of wasabi's health benefits and promising hair growth properties, that have the scientific world buzzing..., you've come to the right place.

Experience the  memorable Fiery Taste, Smooth Finish™ of authentic wasabi, but be forewarned ;-) like exposure to fine wines, one taste of Real Wasabi™ products may leave you forever dissatisfied with "faux wasabi" imitations.

Typically the rhizome will reach a size of six to eight inches long and an inch or so in diameter in approximately twenty four months.

After this initial establishment phase the rhizome begins to build and store reproductive nutrients. It is this concentration of energy which produces the best flavors so the rhizomes are generally the most valued for culinary purposes.  

Wikipedia

6-(Methylsulfinyl) hexyl isothiocyanate (6-MITC or 6-MSITC) is a compound within the isothiocyanate group of organosulfur compounds. 6-MITC is obtained from cruciferous vegetables, chiefly wasabi. Like other isothiocyanates, it is produced when the enzyme myrosinase transforms the associated glucosinolate into 6-MITC upon cell injury.

It is a trend in Japan to apply freshly grated wasabi stem to the hair.  the world's largest wasabi producer, claims that 6-MITC promotes hair regrowth.