Does Human Scent on Lures or Flies Really Matter?

While bonefishing last weekend in Bimini, legendary guide Ansil Saunders commented that a true bonefish pro touches his fly as little as possible and never uses his mouth to clip off the tag ends of the leader. He was not the first guide I've ever fished with that mentioned human scent.

A Florida Keys guide once told me that Berkley Gulp! lures lose a lot of their effectiveness once touched by human hands. A Northeast smallmouth guide once asked me to wait to apply sun block until after tying on my spinnerbait. But to tell you the truth, I can't think of one scenario where I was confident a fish refused my lure or fly because it was laced with human odor, or sun block traces, or mustard from my turkey sandwich.

There are companies out there, such a ZorbX, that make liquids in little spray bottles that are supposed to remove any unnatural odor from lures, flies, and line. It's even endorsed by the North American Fishing Club. I've never tried it, but I wonder if any of you have used similar products, or rely on them frequently. How much stock do you put in tainting your artificials with human scent?