If you thought licorice was just a treat, think again. Licorice root displays a number of actions within the body and features in the treatment plans of many herbalists. Although it is primarily used as a remedy for the adrenal glands, licorice does have other uses. Because it affects steroid hormones, its effect on sex hormones has drawn attention from individuals who wish to lower libido.
Over the course of the past few centuries, licorice has featured in a variety of treatment protocols in traditional Chinese medicine as well as a number of recipes for sweets. Beyond it's distinctive flavor, alternative practitioners now make use of its effects on the body to balance the adrenal glands, which can have significant effects on the sex hormones.
Libido and sex drive fall under the control of the sex hormones, in particular testosterone and estrogen. Both of these hormones are stimulated through the hypothalamic-pituitary-gonad axis, which works on reduced feedback. When levels of these hormones drop, the hypothalamus senses this, prompting the pituitary gland to send a signal to the testes or ovaries to increase production. Receptors in the brain responsible for sex drive require sufficient levels of the hormones to bind to them, which explains why low testosterone counts correlate to low libido. Although many people consider testosterone, an androgenic hormone, to only affect males, it also confers notable effects on females, too. Michael Colgan, a nutritionist and author of 18 books on natural health, notes how the lowered testosterone found in women after menopause often results in low libido.
Glycerrhizinic acid is considered to be the active ingredient in licorice root and is responsible for the majority of the herb's effects in the human body. The most important effect surrounds licorice root's ability to modulate cortisol levels. Researchers from the University of Maryland Medical Center note that glycerrhizinic acid inhibits the liver's ability to deactivate cortisol in circulation. As a result, serum levels of this steroid hormone rise. Cortisol helps boost blood sugar levels, provides anti-inflammatory properties and also inhibits the action of other steroid hormones by competitively binding at receptors. Higher levels of cortisol reduce the action of testosterone in this way and also by reducing stimuli for testosterone at the pituitary gland, according to Dr. Robert Kapolsky in his book on stress, "Why Zebras Don't Get Ulcers."
A study that looked into the effect on licorice supplementation in men, published in the New England Journal of Medicine in 1999, showed that testosterone levels were reduced in those who took the licorice supplements. Further research found that 240 to 525mg of licorice root reduced testosterone by 1/3, relative to the control group, an effect they believed was related to an inhibition of the 17beta-hydroxysteroid dehydrogenase enzyme, which helps manufacture testosterone from precursor hormones.
You may find licorice root in many health food shops as a food supplement. Although it can be cultivated in the wild, most consumption of the herb occurs through capsules or teas. To use licorice root medicinally, a standardized extract provides a reliable dose of the active ingredient, glycerrhizinic acid.
- University of Maryland Medical Center: Licorice Root
- PubMed: Reduction of Serum Testosterone in Men by Licorice
- PubMed: Glycyrrhizin and Serum Testosterone Concentrations in Male Patients With Type 2 Diabetes
- "Hormonal Health"; Dr. Michael Colgan; 2002
- "Why Zebras Don't Get Ulcers"; Dr. Robert Kapolsky; 2002