Title: Physical properties of alpha-keratin fibers
Author: Feughelman, M
Journal: J Soc Cosmetic Chemists, 33:385-406, Dec 1982
Alpha-keratin fibers are produced by mammals as nails and hair.
This article was submitted to FDA as part of the 510(k) submission of Guaranty Hair Removal (GHR) ( Stephens, 1990). Stephens Manufacturing continues to claim the article proves that the GHR electric tweezer can cause enough electricity to travel through a hair to kill a hair follicle.
In reality, Feughelman’s findings refute GHR’s claims.
Summary of Feughelman’s findings
Hair is a poor conductor of electricity
Feughelman notes that fibers with 7% water content have a resistivity 3 x 1012 ohm-cm at room temperature (p. 392)
Even hair with high moisture is a poor conductor of electricity
He states: “The electrical conductivity of an alpha-keratin fiber is very dependent on the water content of the fiber” (p. 392). Feughelman also notes that even fibers with high water content (25%) have a resistivity 6 x 106 ohm-cm at room temperature (p. 392)
Hair internal structures absorb water poorly
He states: “Ample evidence exists for the presence of a highly ordered structure of low water penetrability within the keratin fibers” (p. 393). And: “X-ray evidence suggests that water sorbtion in an alpha-keratin fiber is mainly confined to the non-crystalline regions” (p. 391). He concludes: “Again the evidence points strongly to the lack of interaction of water with the organized alpha-helical structure within the keratin fibers” (392).
Feughelman reviews other conductivity tests
Because electric tweezer makers have cited him as an authority, Dr. Feughelman was asked to review the unpublished clinical data of Mark van Orden of R.A. Fisher Co.
The van Orden tests again show that hair is a poor conductor of electricity, and that hair itself cannot conduct enough electricity through the shaft to kill the root, a common claim by electric tweezers. Dr. Feughelman describes keratin found in hairs as a form of protonic semiconductor (as opposed to an electronic semiconductor) and that the indicated water content of a hair fiber is not liquid water, but at best a hydrogen bonded network of H2O molecules. Feughelman states that “hair is an excellent insulator” and such water content in the hair would not conduct measurable current.
“All the calculations made by R.A. Fischer Co. Inc. have been checked by me and I find them correct. I have read through the Human Hair Conductivity Tests by the laboratories R.A. Fischer Co. Inc. and commend their thoroughness. As expected the tests show no measurable current at the microamp level. 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.”
Feughelman on conductive gels applied to hair
Because electric tweezers like GHR use a conductive gel, Feughelman further confirmed that the application of a gel or conductive solution would form a coating on the hair surface through which current might flow, not through the hair fiber itself.
Dr. Feughelman’s comments echo concerns of other specialists, who question GHR’s effectiveness. The specialists below both discuss how electricity traveling down the outer hair shaft would dissipate when it reached the skin.
FDA Special Product Engineer Paul Ruggera, ( Ruggera, 1991), who reviewed the GHR 510(k) submission ( Stephens, 1990)
Dermatologist James Schuster, M.D. ( Schuster, 1992).
Acknowledgement: Thanks to Max Feughelman for his insights and to Mark van Orden for sharing personal correspondence.
Credentials: Dr. Max Feughelman, BSc, DSc, ASTC, FAIP, is Professor Emeritus of the School of Fiber Science and Technology at University of New South Wales, Sydney. He is an expert in the physical properties of human hair. He contributed the chapters on hair characteristics in Hair and Hair Care (ed. by Dale H. Johnson New York, NY, Marcel Dekker Inc, 1997) and serves as director of Fibrous Keratin Consultants in NSW, Australia. He is also author of Mechanical Properties and Structure of Alpha-Keratin Fibres: Wool, Human Hair, and Related Fibres, (University of New South Wales Press, Sydney, Australia. 1st Edition, 1997).