Licorice reduces testosterone
Italian researchers conclude that licorice even
in the small amounts eaten by many people can cause a significant
drop in testosterone levels in men and this in turn can result in
a loss of libido and other sexual dysfunctions. Licorice is widely used as a flavouring agent in
candies, breath mints, and throat lozenges. The active ingredient
in licorice, glycyrrhizic acid, has strong hormonal effects and
can block the conversion of androstenedione to testosterone.
Researchers at the Universities of Padua and Sassari report
that men who eat licorice may lower their testosterone levels
enough to decrease their libido (sex drive). The experiment
involved seven normal young men who consumed seven grams of a
commercial licorice preparation daily for seven days. The
glycyrrhizic acid content of the licorice tablets was 0.5 gram.
The men had blood samples drawn at the start of the experiment,
four days and seven days into the experiment, and four days after
its conclusion. The average serum level of testosterone before
licorice ingestion was 740 ng/dL; after four days it had dropped
to 414 ng/dL, and after seven days it was 484 ng/dL. The value
four days after cessation of licorice intake reverted back to
normal (704 ng/dL). Licorice consumption has also been linked to the development of
hypertension.
Armanini, Decio, et al. Reduction of serum testosterone in men by
licorice. New England Journal of Medicine, October 7, 1999, p.
1158 (letter to the editor)
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