Depending on who you believe, Enzyte and the dozens of other male enchancement products are worthless overpriced capsules meant to enrichen the manufacturers at the expense of the naiive customer. Here in Southern California, another boiler room operation was recently shut down selling penis pills that promised to "add three inches of manhood." It was no different than many other lawsuits brought by the FDA against manufacturers such as "Longitude" who's fatal downfall was a money back guarentee which it failed to deliver on. The more cunning and shrewd enhancement manufacturers (such as Enzyte) have extensive CYA wording in the website ads mixed in with the pseudo- pharmachology and promises.
The ads borrow heavily from the mystic herbal Far East for inspiration where Tantra and Kung- Fu were born, and Shaolin priests could supposedly keep hard-ons for days. It's also the same culture known for being stereotypically hung like cocktail sausages.
In the end there may be some medical science beyond the placebo effect. L-Arginine and Zic, both listed as ingredients in Enzyte (along with Yohimbe Extract, Ginko Biloba, and secret sauce) have been shown to increase blood flow to the penis.