Glycyrrhiza glabra L. and/or Glycyrrhiza inflata Bat. and/or Glycyrrhiza uralensis Fisch. · herb
Evidence tier: weak
Soothes digestive tract, supports adrenals, and has anti viral properties
Glycyrrhizin, once converted to glycyrrhetinic acid, blocks 11beta hydroxysteroid dehydrogenase type 2, the kidney enzyme that normally inactivates cortisol. Cortisol then accumulates and stimulates the mineralocorticoid receptor as though it were aldosterone, driving sodium retention, potassium loss and rising blood pressure. This mechanism is well established and is the direct cause of the toxicity, which is unusual: for most botanicals the mechanism explains a hoped for benefit, whereas for licorice the best characterised mechanism explains the harm. A separate demulcent action, in which mucilage coats and soothes mucous membranes, is the traditional rationale for the cough and throat use.
Weak on efficacy, and the safety profile is the headline. Start with the authority: NCCIH states that some studies of licorice in people have been completed, but there isn't enough high quality evidence to clearly support its use for any health condition. Europe's regulator, the EMA HMPC, registers liquorice root as a TRADITIONAL herbal medicinal product, resting on long standing use rather than trial evidence, for relief of coughs associated with colds and for symptoms of dyspepsia, and the assessment report carries a limit of 4 to 6 weeks of use without medical advice. The best positive finding in the literature is a route trap and must not be miscredited: MSK reports that systematic reviews have confirmed benefits of TOPICAL licorice, meaning a gargle, in preventing postoperative sore throat. That is a mouth rinse in surgical patients and it says nothing about swallowing a licorice supplement. For the oral product the honest evidence is a small and mixed set of trials in functional dyspepsia and gastric ulcer, several run on branded low glycyrrhizin extracts by parties with a commercial interest, and one randomised trial of 96 gastric ulcer patients found NO difference between deglycyrrhizinated licorice and placebo in healing or ulcer area at four weeks. Safety is where this ingredient actually earns attention. Glycyrrhizin inhibits the renal enzyme 11beta HSD2, producing pseudohyperaldosteronism: hypertension, hypokalaemia and oedema. NCCIH states glycyrrhizin can cause serious adverse effects such as irregular heartbeat and cardiac arrest, and that even small amounts have been linked to severe adverse effects in people who eat a lot of salt, people with hypertension, and people with heart or kidney conditions. Severe hypokalaemia can progress to QT prolongation, arrhythmia and death, and cardiac deaths from heavy liquorice consumption are documented in the case literature. The FDA warns that eating multiple 2 ounce bags of black liquorice a day for at least two weeks, if you are 40 or older, can land you in hospital with an arrhythmia. Note that NIH LiverTox assigns licorice likelihood score E, an unlikely cause of liver injury, which is a genuine clearance for the LIVER specifically and must not be read as a general safety clearance, because the danger here is cardiovascular and electrolytic, not hepatic.
As an EMA registered traditional herbal medicine for digestive symptoms, a tea of 1.5 to 2 g of comminuted root in 150 ml of boiling water, 2 to 4 times daily, for no longer than 4 to 6 weeks without medical advice. Glycyrrhizin intake is the number that actually matters and should be kept low. DGL, deglycyrrhizinated licorice, is a DIFFERENT PRODUCT with the glycyrrhizin removed and therefore without the pseudohyperaldosteronism risk; NCCIH indicates DGL might be safe for up to 4 months. Whole licorice and DGL must never be treated as interchangeable.
DGL: chew 20 minutes before meals. Whole root: limit to short term use only.
Onset: ~14 days
Avoid in pregnancy, glycyrrhizin is associated with increased risk of preterm birth and adverse neurodevelopmental outcomes. Long term use (>4 to 6 weeks) can cause pseudohyperaldosteronism: sodium retention, hypertension, hypokalaemia. Contraindicated in hypertension, kidney disease, and liver cirrhosis.
Pregnancy: avoid
Breastfeeding: caution
Used for over 4,000 years in ancient Assyrian, Egyptian, Chinese, and Indian medicine. One of the most frequently used harmonising herbs in Traditional Chinese Medicine formulas. The deglycyrrhizinated (DGL) form used for gut support removes the compound responsible for raising blood pressure, making it safer for longer term use.
Active compounds: glycyrrhizin (glycyrrhizic acid), glycyrrhetinic acid, liquiritin, isoliquiritigenin
Remedies using Licorice Root · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.