Licorice Root: Latest Research & Evidence Update
Licorice root (Glycyrrhiza glabra, Glycyrrhiza uralensis) is one of the most ancient medicinal plants in recorded history, used in traditional medicine across Central Asia, Europe, and China. Modern research has largely focused on its primary active compound, glycyrrhizin (and its metabolite glycyrrhetinic acid), as well as flavonoids like glabridin and liquiritigenin. This update covers what current evidence shows, where the picture has sharpened, and what remains unresolved.
What Recent Trials Show
Gastrointestinal health remains the best-supported application for licorice root in clinical research. A randomised double-blind trial found that a standardised licorice root extract significantly improved dyspepsia symptoms β including heartburn, bloating, and nausea β compared to placebo over a four-week period (Raveendra et al., 2012). The mechanism likely involves both the soothing effects of mucilaginous compounds on the gastric mucosa and modest anti-inflammatory activity.
For helicobacter pylori (H. pylori), glycyrrhizin and deglycyrrhizinated licorice (DGL) have been studied as adjuncts to standard eradication therapy. Evidence suggests DGL may support mucosal healing but does not eradicate H. pylori independently β it is an adjunct, not a standalone treatment.
On cortisol metabolism: glycyrrhizin inhibits the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), which normally converts active cortisol to inactive cortisone in the kidneys. This inhibition increases local cortisol activity, which can cause sodium retention, potassium loss, and elevated blood pressure at high doses or with prolonged use.
Shifts in Consensus
The evidence picture for licorice root has sharpened in two directions:
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DGL formulations (deglycyrrhizinated licorice, where most glycyrrhizin is removed) are now recognised as the appropriate form for gut health applications, specifically because they retain the beneficial mucosal effects while substantially reducing the cortisol-related safety concerns of whole-root glycyrrhizin.
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Caution around whole-root licorice in high doses has been reinforced by case reports and pharmacological data. Daily glycyrrhizin above approximately 100 mg per day consumed long-term has been associated with pseudohyperaldosteronism β fluid retention, hypertension, and hypokalemia. This is a real risk that is not always communicated in popular supplement content.
OstroVit Licorice VEGE 90caps is available at maxfit.ee for those interested in a standardised licorice supplement.
Still-Open Questions
Several clinically important questions remain unresolved:
- Optimal dose thresholds: defining safe chronic daily glycyrrhizin intake precisely is complicated by the variability between individuals in 11beta-HSD2 activity.
- Cancer-related research: preliminary in vitro and animal studies suggest licorice flavonoids may have anti-tumour properties, but no well-powered human clinical trials confirm this; it should not be cited as a clinical benefit.
- Hormonal effects in women: some research suggests glabridin may have weak estrogenic activity. The clinical significance for women at typical supplemental doses remains unclear.
- Interaction with antihypertensives and corticosteroids: the cortisol-sparing mechanism of glycyrrhizin means caution is warranted when combining with blood pressure medications or corticosteroid therapies.
What It Means Practically
For digestive discomfort and mild gastric irritation, DGL licorice has a reasonable evidence base and a good safety profile at typical doses. Whole-root licorice at high doses or for extended periods carries meaningful blood pressure and electrolyte risks. The practical guidance is:
- For gut health support: favour DGL formulations; read labels to understand glycyrrhizin content.
- Limit daily glycyrrhizin intake; if you are prone to hypertension or taking antihypertensives, whole-root licorice is not appropriate without medical guidance.
- Short-term use (four to eight weeks) is safer than open-ended supplementation.
FAQ
What is the difference between licorice and DGL?
DGL stands for deglycyrrhizinated licorice β it is licorice root extract from which most of the glycyrrhizin has been removed. DGL retains gut-soothing properties but has substantially reduced cortisol-related and blood pressure side effects compared to full-spectrum licorice root. For digestive applications, DGL is generally the preferred form.
Can licorice root raise blood pressure?
Yes. Whole-root licorice consumed in large amounts or over long periods can inhibit 11beta-HSD2, leading to sodium retention and elevated blood pressure. Case reports document significant hypertension from high licorice consumption. The effect is dose- and duration-dependent; occasional modest amounts in food or standard supplemental use of DGL are generally safe.
Is licorice root safe for everyone?
No. People with hypertension, heart conditions, kidney disease, low potassium levels, or those taking corticosteroids or antihypertensive medications should avoid significant whole-root licorice intake and consult a physician before supplementing. Pregnant women should also avoid high doses.
References
Raveendra, K. R., Jayachandra, Srinivasa, V., Srinidhi, K. S., Allen, J. J., Goudar, K. S., ... & Venkateshwarlu, K. (2012). An extract of Glycyrrhiza glabra (GutGard) alleviates symptoms of functional dyspepsia: a randomized, double-blind, placebo-controlled study. Evidence-Based Complementary and Alternative Medicine, 2012, 216970. https://pubmed.ncbi.nlm.nih.gov/21747893/
Asl, M. N., & Hosseinzadeh, H. (2008). Review of pharmacological effects of Glycyrrhiza sp. and its bioactive compounds. Phytotherapy Research, 22(6), 709-724. https://pubmed.ncbi.nlm.nih.gov/18446848/
Stormer, F. C., Reistad, R., & Alexander, J. (1993). Glycyrrhizic acid in liquorice β evaluation of health hazard. Food and Chemical Toxicology, 31(4), 303-312.
