Topically applied glycyrrhizic acid causes hair removal in rats.
BACKGROUND
Anecdotic reports from Turkmenistan suggest an epilatory effect of sweet licorice extract after topical application.


OBJECTIVE
This study examines hair removal after topical application of glycyrrhizic acid, the main compound of sweet licorice.


METHODS
An aqueous solution containing 15% of the ammonium salt of glycyrrhizic acid, 10% urea, and 20% ethanol was topically applied two times per day on the neck areas of Wistar rats using a toothbrush.


RESULTS
After 3 d, 20-30% of the treated areas were free of hair. After treatment for 6-12 d, 90-95% of the hair was gone. Clinical as well as immunohistological examinations showed no signs of inflammation even after long-term treatment for more than 9 months. Interestingly, long-term treatment reduced the regrowth of hair of about 20%. Examination by scanning electron microscopy showed a smoothed hair cuticle that might facilitate detachment of the hair shaft from the follicular wall.


CONCLUSIONS
Our findings suggest glycyrrhizic acid as an interesting molecule for treating hypertrichosis in humans.
Department of Dermatology, Venereology and Allergology, Johann Wolfgang Goethe University, Frankfurt/Main, Germany and.
Julijana
J
Ivosevic-Zaper
Matthias
M
Hofmann
Ayna
A
Kakadjanova
Eva
E
Valesky
Markus
M
Meissner
Jürgen
J
Bereiter-Hahn
Roland
R
Kaufmann
August
A
Bernd
Stefan
S
Kippenberger
D000287:Administration, Topical; D000818:Animals; D005260:Female; D019695:Glycyrrhizic Acid / Q000008:administration & dosage*; D018859:Hair Follicle / Q000187:drug effects* / Q000254:growth & development*; D006204:Hair Removal / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar
D019695:Glycyrrhizic Acid
Epilation; hirsutism; licorice