Genuinely effective for several things, and the herb most likely to raise your blood pressure. — Glycyrrhiza glabra
remedyLicorice Glycyrrhiza glabra — hand-drawn plate, stylised. Not for identification — use a field guide and verify with a second source before eating any wild plant.
Licorice (Glycyrrhiza glabra) is unusual in having real trial evidence for specific conditions while carrying one of the most important safety warnings in the pharmacopoeia.
What it does. Deglycyrrhizinated licorice (DGL) has evidence for dyspepsia and ulcer symptoms — the DGL form removes the glycyrrhizin that causes the blood-pressure problem. Licorice root also has evidence for sore throat (as a demulcent) and traditional use for cough.
The safety warning is not theoretical. Glycyrrhizin causes pseudohyperaldosteronism: sodium retention, potassium loss, raised blood pressure, oedema and, in serious cases, hypokalaemia with arrhythmia. Cases of licorice-induced hypertension and hospitalisation are documented, including from confectionery and from tea consumed in quantity. Anyone with hypertension, heart disease, kidney disease, or on diuretics or antihypertensives should use DGL or nothing.
Long-term use is the risk pattern — it is a dose-and-duration effect. A short course of DGL is fine; a daily licorice habit is not.
The real root, worth growing if you live somewhere it will grow (it wants deep, sandy soil and warmth); most licorice is wild-harvested.
What the studies found
Meta-Analysis2019Archives of toxicology
Identification of glycyrrhizin metabolites in humans and of a potential biomarker of liquorice-induced pseudoaldosteronism: a multi-centre cross-sectional study.
This is the first study to identify the association between a novel metabolite, compound 3, and the incidence of pseudoaldosteronism, highlighting it as a promising biomarker.
Randomized Controlled Trial2018Journal of cosmetic dermatology
Randomized investigator-blinded comparative study of moisturizer containing 4-t-butylcyclohexanol and licochalcone A versus 0.02% triamcinolone acetonide cream in facial dermatitis.
The test facial moisturizer was slower than 0.02% TA in improving facial dermatitis, but showed greater benefit in erythema control and skin hydration.
Randomized Controlled Trial2016Phytotherapy research : PTR
Hepatoprotective Effects of a Proprietary Glycyrrhizin Product during Alcohol Consumption: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study.
Glycyrrhizin, the primary active compound, has been shown to suppress elevations in liver enzymes that occur when the liver becomes diseased or damaged.
Randomized Controlled Trial2015Journal of pharmaceutical sciences
Pharmacokinetic Profiles of Active Components After Oral Administration of a Kampo Medicine, Shakuyakukanzoto, to Healthy Adult Japanese Volunteers.
The results of this pharmacokinetic trial in humans are also important and useful for understanding the mechanism of action of SKT, verifying the active components predicted in basic research, and conducting pharmacokinetics and safety studies in the future.
| | |
|---|---|
| Life | Herbaceous perennial |
| Propagation | Root cuttings, or division |
| Light | Full sun |
| Soil | Deep, sandy, well drained — the root is the crop |
| Harvest root | Autumn of year 3-4 |
| Dry | 45-55 C, sliced |
| Note | Wants a long warm season; marginal here |
Grow it mainly for curiosity — commercial licorice is mostly wild-harvested, and the DGL form people actually want is a processed product.
Preparation
DGL (deglycyrrhizinated licorice) — the form for gut symptoms; chewable tablets before meals, as directed. This is the safe form for regular use.
Whole licorice root tea — 1 teaspoon per cup. Short courses only, and not at all if hypertensive.
Sore throat — a licorice demulcent preparation, often with marshmallow and slippery elm.
Do not take whole licorice root alongside diuretics or blood-pressure medication.
Cautions and interactions
Glycyrrhizin raises blood pressure and lowers potassium. Avoid whole licorice with hypertension, heart disease, kidney disease, or on diuretics or antihypertensives.
Use DGL for anything regular — it removes the culprit compound.
Long duration is the risk. A daily licorice habit can cause hypertension and hypokalaemia.
Avoid in pregnancy — associated with preterm birth in epidemiological studies.
Licorice confectionery and tea both count towards the dose.
When this is not a self-care problem — get help
Headache, ankle swelling, muscle weakness or palpitations while using licorice — stop and get assessed; possible hypokalaemia and hypertension.
Severe headache with visual disturbance — urgent assessment.
Known interactions
Interacts with diuretics, antihypertensives, corticosteroids and digoxin; causes potassium loss.
Identification of glycyrrhizin metabolites in humans and of a potential biomarker of liquorice-induced pseudoaldosteronism: a multi-centre cross-sectional study. Archives of toxicology 2019; doi:10.1007/s00204-019-02588-2 PubMed 31605160
Effectiveness of licorice in preventing dental caries in children: A systematic review. Journal of the Indian Society of Pedodontics and Preventive Dentistry 2020; doi:10.4103/JISPPD.JISPPD_100_20 PubMed 33402612
Randomized investigator-blinded comparative study of moisturizer containing 4-t-butylcyclohexanol and licochalcone A versus 0.02% triamcinolone acetonide cream in facial dermatitis. Journal of cosmetic dermatology 2018; doi:10.1111/jocd.12499 PubMed 29411520
Combined Lifestyle and Herbal Medicine in Overweight Women with Polycystic Ovary Syndrome (PCOS): A Randomized Controlled Trial. Phytotherapy research : PTR 2017; doi:10.1002/14651858.CD007535.pub2 PubMed 28685911
Hepatoprotective Effects of a Proprietary Glycyrrhizin Product during Alcohol Consumption: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study. Phytotherapy research : PTR 2016; doi:10.1002/ptr.5699 PubMed 27539273
Pharmacokinetic Profiles of Active Components After Oral Administration of a Kampo Medicine, Shakuyakukanzoto, to Healthy Adult Japanese Volunteers. Journal of pharmaceutical sciences 2015; doi:10.1002/jps.24596 PubMed 26211516