LeMaster, 1990 As part of the GHR 510(k) submission to FDA ( Stephens 1990), the manufacturer
paid Edwin LeMaster to perform tests on human hair conductivity.
LeMaster compiled an unpublished report that echoes observations
made by similar reports:
Hair is a poor conductor of electricity.
Wet hairs conduct better than dry,
but they're still a poor conductor.
The tiny amount of electricity is conducted
along the outer hair, not through it.
LeMaster's study is flawed. Where the Feughelman study he cites
measured water content in hair to ensure a controlled experiment,
LeMaster does not measure moisture content of hairs. He acknowledges
this flaw, stating, "Further studies of these electrical
properties will be carried out using samples for which the moisture
content can be documented."
Despite some methodological issues, LeMaster concludes that using
a conductive solution similar to those sold as part of GHR treatment
"only affects the outer surface resistance because when the
sample is exposed to the atmosphere the surface dries out and
the resistance promptly increases."
For similar conclusions, see:
van Orden, 1998
van Orden states: "Soaking or coating the hair shaft with
an electrolyte can, of course, provide a conductive path along
the outside surface of the hair, but studies indicate
that such applied current would likely dissipate through the
skin at the follicle opening and not penetrate fully to the
papilla. Any test of hair conductivity must eliminate the effects
of possible current flow along the hair surface through a conductive
coating."
Feughelman, 1982
Commenting on the van Orden study above, Feughelman states,
"The only way to obtain any significant current flow would
be to apply to the hair fibre some kind of conducting electrolyte
in the form of possibly a gel to obtain sufficient conduction
on each hair fibre."
Schuster, 1992
Schuster notes that "a very small current can be conducted
over the hair surface through the electrolyte coating, not the
hair fiber itself. In addition, such current would readily diffuse
upon contact with the follicle walls past the infundibulum and
little, if any, would reach the papilla."
Schuster also conclusively demonstrated that energy stops traveling
down a hair upon contact with a more conductive surface like
skin, as hypothesized in Ruggera (1991).
|
hair removal
facts
for consumers
