Ruggera memo, April 1991
FDA Special Product Engineer Paul Ruggera was assigned to evaluate the GHR electric tweezer in the course of their 510(k) review.
After verifying the device’s output was within stated parameters, Mr. Ruggera performed a test of the amount of energy being delivered to a hair. He tested hairs on his right forearm according to manufacturer instructions. Each hair tested when grasped according to instructions presented a resistance of 0.5 M to 1 M ohm. When the tweezers touched his skin that had been wetted with the manufacturer’s electrolytic solution, the resistance jumped to about 30 k ohm, or about two orders of magnitude greater. Ruggera concludes with the obvious question any electrical engineer would ask:
"Does this energy get to the hair follicle, or is it merely dispersed when it meets the lower resistance of the wetted skin surface area?"
This sums up the basic flaw in the theory and practice of electric tweezing: any energy traveling down a hair will disperse across the skin rather than continue down the hair. This is called "the path of least resistance," and it’s one of the most basic laws of electricity. Electricity travels on the most conductive path available, and since skin is much more conductive than hair, electricity from an electric tweezer will simply disperse across the skin. This is even more true when skin is coated in conductive gel, as shown in Schuster, 1992.
FDA stated in 1998 that there is no body of significant information establishing the effectiveness of electric tweezers to permanently remove hair. FDA’s decision has left some unanswered questions about the status of what GHR can and cannot claim. I have analyzed this faulty submission and reported my findings to FDA in a petition for administrative reconsideration.
Download my full GHR petition from FDA’s website (warning: very large Adobe Acrobat file)
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