Licorice: benefits, dosage, contraindications
Scientific name(s)
Glycyrrhiza glabra
Family or group:
Plants
Active ingredients:
Glycyrrhizin
Indications
Scoring methodology
EFSA approval.
Gastric ulcer ✪✪✪✪✪
The anti-inflammatory, muco-protective and anti-ulcer activities of licorice make it an interesting treatment for gastro-duodenal ulcer. Although these effects have been attributed to the constituents glycyrrhizin and glycyrrhetinic acid, deglycyrrhizinated licorice (DGL), which contains < 3% glycyrrhizin, has also been studied and appears to produce the most promising results when used long-term. Licorice helps transform unspecialized cells into mucus-producing cells and increases the production and release of mucus. A randomized, placebo-controlled study (n = 100) showed that a root extract of Glycyrrhiza glabra significantly reduced Helicobacter pylori burden compared with placebo, as assessed by the 13C-urea breath test and the H. pylori stool antigen test. In an uncontrolled trial of 32 patients with chronic duodenal ulcer, 3800 mg/day of deglycyrrhizinated licorice (divided into five doses) produced signs of healing in all cases and a complete restoration of the mucosa in a majority of subjects. Although treatment was continued for 24 weeks, substantial improvement was noted in 56% of patients at week 12 and in 78% at week 16. By contrast, a shorter 4-week trial of 96 patients with gastric ulcer did not yield the same positive results. Deglycyrrhizinated licorice combined with an antacid was as effective as cimetidine (200 mg three times daily plus 400 mg at night) after 6 weeks, according to a single-blind randomized trial of 100 volunteers with gastric ulcer. Both treatments continued to show similar results after 12 weeks, and recurrence rates after tapering off both medications were also similar. Commission E approves the use of licorice in the treatment of gastric and duodenal ulcers.
Posologie
By mouth: root
100 - 900 mg
powder, tisane/tea/infusion, mother tincture, dry extract
Effect of GutGard in the Management of Helicobacter pylori: A Randomized Double-Blind Placebo-Controlled Study
Fermented milk containing Lactobacillus paracasei and Glycyrrhiza glabra has a beneficial effect in patients with Helicobacter pylori infection: A randomized, double-blind, placebo-controlled study
Treatment of duodenal ulcer with glycyrrhizinic-acid-reduced licorice: A multicenter trial
To evaluate the effect of adding licorice to the standard treatment regimen for Helicobacter pylori.
Deglycyrrhizinated licorice (DGL) and the renewal of rat stomach epithelium
Clinical trial of deglycyrrhizinated licorice in gastric ulcer.
Comparison between cimetidine and Caved-S in the treatment of gastric ulceration, and subsequent maintenance therapy
A comparison of carbenoxolone sodium and deglycyrrhizinated licorice in the treatment of gastric ulcer in ambulatory patients
Deglycyrrhizinated licorice in duodenal ulcer
Eczema ✪✪✪✪✪
The application of gel formulations containing 1% or 2% licorice root extract three times a day for two weeks appears to reduce erythema, edema, and itching. The 2% gel is more effective than the 1% gel. The anti-inflammatory effect induced by glycyrrhetinic acid provides a theoretical basis for its use as a topical anti-inflammatory agent (similar to hydrocortisone) in the treatment of dermatitis. In practice, glycyrrhetinic acid has been used to potentiate the effects of weak steroids (such as hydrocortisone) to increase pharmacologic effects without the need for more powerful corticosteroids. It is assumed that increasing corticosteroid activity in this way will not lead to an increase in adverse effects; however, no study has yet confirmed this hypothesis. A study comparing the effects of ointments containing hydrocortisone and glycyrrhetinic acid in dermatitis found that hydrocortisone was generally superior in acute and childhood eczema, while glycyrrhetinic acid was superior in chronic and subacute conditions. It should be noted that glycyrrhetinic acid may have more pronounced anti-inflammatory effects than glycyrrhizin. Glycyrrhetinic acid is not present in licorice but is produced in the gastrointestinal tract from glycyrrhizin; therefore, it is not certain that topical preparations containing pure licorice could produce the same effects.
Posologie
Topical: root
gel, ointment, cream
Canker sores ✪✪✪✪✪
Clinical research shows that applying an oral patch containing licorice at 0.015-0.229 mg/kg for 16 hours each day for 8 days does not affect ulcer healing time, but reduces ulcer size and post-stimulus pain compared with placebo. nnA small clinical study also shows that applying bioadhesive hydrogel patches containing 1% licorice extract reduces pain, as well as the diameter of necrosis and the inflammatory halo of recurrent aphthous ulcers, compared with baseline. Mouthwashes containing licorice have also been used. nnA clinical trial shows that swishing a diphenhydramine and 5% licorice extract solution in the mouth for about 3 minutes, four times a day, until the aphthous ulcers heal, reduces mean healing time compared with a solution containing diphenhydramine alone. Pain was reduced by up to 69% more in people using the licorice extract.nnPreliminary clinical research shows that gargling warm water containing 200 mg of deglycyrrhizinated licorice powder four times a day for 7 days improves pain in 75% of patients on day one and results in complete healing in 75% of patients on day three.nn
Posologie
By mouth: root
gel, patch, mouthwash
The effects of licorice containing diphenhydramine solution on recurrent aphthous stomatitis: A double-blind, randomized clinical trial
The efficacy of the bioadhesive patches containing licorice extract in the management of recurrent aphthous stomatitis
Deglycyrrhizinated licorice in aphthous ulcers
Hepatitis ✪✪✪✪✪
In some preliminary clinical studies, a specific intravenous preparation containing glycyrrhizin appears to reduce mortality from viral hepatitis by about 50%. Other clinical research suggests that the same product reduces serum alanine aminotransferase (ALT) in patients with hepatitis C but does not improve hepatitis C virus RNA levels. When used long-term, this preparation appears to reduce the risk of hepatocellular carcinoma in patients with hepatitis C, compared with long-term use of other supplements such as vitamin K. The product has been used at different doses: 40 or 100 mL, containing 2 mg of glycyrrhizin, 1 mg of cysteine and 20 mg of glycine per mL of solution, administered daily for 4-8 weeks; other dosages have been used intravenously. Other research shows that this preparation reduces ALT, aspartate aminotransferase (AST) and gamma-glutamyl transpeptidase (GGT) in patients with hepatitis B virus. To date, oral licorice has not been evaluated for this purpose.
Posologie
Intravenous: root
600 - 900 mg
powder, mother tincture, dry extract
A preliminary open trial on interferon stimulator (SNMC) derived from Glycyrrhiza glabra in the treatment of subacute hepatic failure
The long-term efficacy of glycyrrhizin in chronic hepatitis C patients
Antiviral Effects of Glycyrrhiza species
[Effectiveness of interferon, glycyrrhizin combination therapy in patients with chronic hepatitis C]
The efficacy of licorice root extract in decreasing transaminase activities in non-alcoholic fatty liver disease: a randomized controlled clinical trial
Glycyrrhizin-induced reduction of ALT in European patients with chronic hepatitis C
Digestive disorders ✪✪✪✪✪
Licorice has been evaluated in combination with other plants for dyspepsia. The most studied product is Iberogast, which contains, in addition to licorice, an alcoholic extract of bitter Iberis as well as alcoholic extracts of angelica root, German chamomile flowers, cumin seeds, milk thistle fruits, lemon balm leaves, peppermint leaves, and greater celandine. A meta-analysis of studies using the Iberogast product shows that taking 1 mL orally three times a day for a period of 4 weeks reduces the severity of acid reflux, epigastric pain, cramps, nausea and vomiting compared with placebo. The EMA recommends licorice as a traditional herbal medicinal product for the relief of digestive symptoms, notably the burning sensation and dyspepsia.
Posologie
Orally: root
100 - 900 mg
powder, herbal tea/tea/infusion, mother tincture, dry extract
Synergies
Community herbal monograph on Glycyrrhiza glabra L. and/or Glycyrrhiza inflata Bat. and/or Glycyrrhiza uralensis Fisch., radix
Meta-analysis: phytotherapy of functional dyspepsia with the herbal drug preparation STW 5 (Iberogast)
Treatment of functional dyspepsia with a herbal preparation. A double-blind, randomized, placebo-controlled, multicenter trial
Gastritis ✪✪✪✪✪
In Germany, Commission E emphasizes that clinical trials have demonstrated the healing effect of glycyrrhizin and glycyrrhetic acid on gastric ulcers and chronic gastritis.
Posologie
Oral use: root
100 - 900 mg
powder, tisane/tea/infusion, mother tincture, dry extract
Bronchitis ✪✪✪✪✪
Commission E approves the use of licorice for catarrhs of the upper respiratory tract. The EMA recommends licorice as an expectorant for cough associated with the common cold.
Posologie
Oral use: root
600 - 900 mg
powder, mother tincture, dry extract
Community herbal monograph on Glycyrrhiza glabra L. and/or Glycyrrhiza inflata Bat. and/or Glycyrrhiza uralensis Fisch., radix
Effect of preoperative licorice lozenges on incidence of postextubation cough and sore throat in smokers undergoing general anesthesia and endotracheal intubation
Topical application of licorice for prevention of postoperative sore throat in adults: A systematic review and meta-analysis
Asthma ✪✪✪✪✪
In relation to the antiallergic effects of licorice, it is traditionally recommended for the treatment of allergic conditions such as asthma and dermatitis; however, clinical research is necessary.
Posologie
Oral: root
600 - 900 mg
powder, mother tincture, dry extract
Respiratory infections ✪✪✪✪✪
Animal studies demonstrate a reduction in viral activity for herpes simplex virus, encephalitis and pneumonia caused by influenza A virus; and in vitro studies reveal antiviral activity against HIV-1, the SARS-related coronavirus, respiratory syncytial virus, arboviruses, vaccinia virus and vesicular stomatitis virus. However, until controlled studies are available, the clinical efficacy of this treatment remains unknown. Licorice increases mucus production in the airways and has an expectorant and antitussive effect. Combined with its anti-inflammatory, antiviral and possibly immunostimulant effects, it is a popular treatment for upper and lower respiratory tract infections. In practice, it is often used to treat cough and bronchitis.
Posologie
Oral: root
600 - 900 mg
powder, mother tincture, dry extract
Antiviral Effects of Glycyrrhiza species
Pharmacokinetic and pharmacodynamic profiles of the antitussive principles of Glycyrrhizae radix (licorice), a main component of the Kampo preparation Bakumondo-to (Mai-men-dong-tang)
Community herbal monograph on Glycyrrhiza glabra L. and/or Glycyrrhiza inflata Bat. and/or Glycyrrhiza uralensis Fisch., radix
Stomatitis ✪✪✪✪✪
Licorice is traditionally indicated for inflammations of the ENT tract: laryngitis, sinusitis, stomatitis, thanks to its anti-infective and anti-inflammatory action.
Posologie
Oral use: root
600 - 900 mg
powder, mother tincture, dry extract
Cough ✪✪✪✪✪
The Commission E approves the use of licorice for catarrhal conditions of the upper respiratory tract. The EMA recommends licorice as an expectorant for cough associated with the common cold.
Posologie
Oral use: root
600 - 900 mg
powder, mother tincture, dry extract
Community herbal monograph on Glycyrrhiza glabra L. and/or Glycyrrhiza inflata Bat. and/or Glycyrrhiza uralensis Fisch., radix
Effect of preoperative licorice lozenges on incidence of postextubation cough and sore throat in smokers undergoing general anesthesia and endotracheal intubation
Topical application of licorice for prevention of postoperative sore throat in adults: A systematic review and meta-analysis
Improve adaptability ✪✪✪✪✪
Traditionally, licorice is considered an "adrenal tonic", most likely because of its ability to slow the breakdown of cortisol.nnIt may be useful for patients who are experiencing an allostatic load due to chronic stress and who are therefore unable to mount a healthy stress response. This phenomenon is also known as adrenocortical insufficiency.nnThere are no controlled trials to determine its effectiveness in this situation.nnOne may question whether this effect is desirable in patients who do not have adrenocortical insufficiency and for whom an increase in cortisol levels may be problematic. Chronically elevated cortisol levels have been associated with desensitization of the hypothalamic-pituitary-adrenal axis, insulin resistance, depression, and immunosuppression. nnIn the early stages of stress, increased cortisol levels trigger negative feedback mechanisms to keep stress under control and, consequently, short-term use may be justified, but it is unlikely to be beneficial unless some adrenocortical insufficiency exists.nn
Posologie
Orally: root
600 - 900 mg
powder, mother tincture, dry extract
Effect of the combination of ginseng, oriental bezoar and glycyrrhiza on autonomic nervous activity and immune system under mental arithmetic stress
Chronic pain, chronic stress and depression: coincidence or consequence?
Properties
Anti-inflammatory
Glycyrrhetinic acid, a compound of licorice, acts by increasing cortisol levels and other steroid hormones, thereby contributing to its anti-inflammatory effects. It inhibits certain hepatic enzymes, prolonging the activity of cortisol. nnLicorice is being studied for potentiating the effects of steroids. It also inhibits the production of eicosanoids and the activation of the transcription factor NF-κB. Furthermore, studies show its efficacy against inflammation in various experimental models, including asthma, colitis and edema.nn
Usages associés
Antiviral
Oral and injectable forms of licorice, including glycyrrhizin and glycyrrhizic acid, have demonstrated antiviral activity against various viruses. nnIn humans, these compounds reduce virus-related liver damage from hepatitis B and C viruses. nnAnimal studies show a reduction in viral activity for herpes simplex, encephalitis, and pneumonia caused by influenza A virus. In vitro research also indicates efficacy against HIV-1, the SARS coronavirus, respiratory syncytial virus, various arboviruses, enteroviruses, coxsackieviruses and vesicular stomatitis virus. nnProposed antiviral mechanisms include reduced transport to the cell membrane and inhibition of viral membrane fusion, as well as activation of immune responses such as interferon gamma.nn
Usages associés
Mucolytic
Initial research into the mucoprotective properties of licorice led to the development of drugs such as carbenoxolone and enoxolone to treat gastric and esophageal ulcers. These drugs appear to act by increasing blood flow in the mucosa and mucus production, and by altering the synthesis of gastric prostanoids. Animal studies show that licorice, particularly in deglycyrrhizinated form, promotes healing by stimulating mucus production. In addition to its gastrointestinal effects, licorice has shown expectorant and antitussive properties, possibly related to stimulation of tracheal mucus secretion and tracheal relaxation.
Usages associés
Gastroprotective
Glycyrrhetinic acid and licorice polysaccharides have shown the ability to inhibit strains of Helicobacter pylori in in vitro studies. These compounds also inhibit H. pylori adhesion to the human gastric mucosa. Licorice may also affect prostaglandin metabolism, suggesting a beneficial effect on gastroduodenal ulcers. In vivo studies indicate that aqueous licorice extract reduces ulcer size similarly to famotidine. Deglycyrrhizinated licorice (DGL) appears to accelerate ulcer healing without the side effects of carbenoxolone, a semi-synthetic derivative of glycyrrhetinic acid.
Usages associés
Antibacterial
Licorice is traditionally used as an antimicrobial; in vitro research has shown that it has antifungal activity, as well as activity against Gram-positive and Gram-negative bacteria. Licorice contains constituents such as glabridin, glabrol and 3-hydroxyglabrol that have in vitro antimicrobial activity. Glabridin has been identified as a potentially active agent against Mycobacterium tuberculosis, the cause of tuberculosis. Licorice extracts in water and ether have been found to have antibacterial activity against E. coli, B. subtilis, E. aerogenes, K. pneumoniae and S. aureus. In children at high risk of tooth decay, a pacifier containing licorice extract reduced the number of Streptococcus mutans, a bacterium involved in cavity formation.
Usages associés
Antiallergic
Components of licorice, glycyrrhetinic acid and liquiritigenin, show significant anti-allergic effects. They relieve IgE-induced allergic reactions, reduce anaphylactic reactions and scratching behavior in mouse models. In a mouse model of asthma, glycyrrhizin decreased lung inflammation and levels of interleukins and IgE. These results suggest therapeutic potential for treating allergic conditions such as asthma and dermatitis, although further research is needed to confirm these effects.
Usages associés
Hepatoprotective
Licorice extract, or glycyrrhizin, has a beneficial effect on the liver of rats, increasing the activity of certain important hepatic enzymes such as CYP3A, CYP2B1, and CYP1A2. In rats with liver injury, it decreases markers of liver damage and improves levels of certain essential proteins (albumin and globulin). It also stimulates antioxidant defenses and protects against lipid peroxidation. Preliminary studies in humans suggest that this extract may help reduce markers of liver damage in people with nonalcoholic fatty liver disease.
Usages associés
Antifungal
Licochalcone A and glabridin, components of licorice, have shown antifungal activity against Candida albicans. At high doses, they inhibit hyphal growth, with licochalcone A also reducing biofilm formation. However, it is important to note that these components can be toxic to oral epithelial cells at higher concentrations.
Estrogenic activity
Licorice can act as both an anti-estrogenic and estrogenic agent. Preliminary research shows it limits the growth of estrogen-sensitive breast cancer cells. However, its estrogenic effect may vary depending on concentration. Glabridin, an isoflavone from licorice, stimulates cell growth at low concentrations but has an antiproliferative effect at higher concentrations. Licorice also decreases testosterone production, likely by inhibiting certain key enzymes. It also reduces elevated prolactin levels in men.
Antidepressant
Flavonoids from licorice, such as glabridin, have been shown to inhibit serotonin reuptake (a neurotransmitter important for mood) in a dose-dependent manner in vitro. However, animal effects suggest that the impact may involve norepinephrine and dopamine to a greater extent. In rats, licorice demonstrated an antidepressant effect similar to some drugs, but via an increase in norepinephrine and dopamine levels rather than serotonin. Licorice may act by inhibiting monoamine oxidase (MAO inhibitors are used in the treatment of certain types of depression).
Safe dosage
Adults 18 years and older: 160 mg - 900 mg (dry extract)
- Herbal tea : 1.5 to 2 g of ground plant material in 150 mL of boiling water as an infusion 2 to 4 times a day, or 1.5 to 2 g of ground plant material in 150 mL of water as a decoction 2 to 4 times a day. Take one cup after meals. - Dry extract: 32 mg 2 to 3 times a day for oral use in dyspepsia and 200 to 300 mg three times per day for other indications. - Powder: 3.6 to 6 g corresponding to 100-240 mg of glycyrrhizin. Caution regarding the use of licorice-based products containing glycyrrhizin taken orally in large quantities for several weeks, or in smaller quantities for longer periods. In otherwise healthy people, daily consumption of glycyrrhizin for several weeks or longer can cause serious adverse effects, including pseudo-hyperaldosteronism, hypertensive crisis, hypokalemia, cardiac arrhythmias, and cardiac arrest. Doses of 20 grams or more of licorice, containing at least 400 mg of glycyrrhizin, are more likely to cause these effects. However, smaller amounts have also caused hypokalemia and associated symptoms when taken for months or years. In patients with hypertension, cardiovascular or renal problems, or with high salt intake, as little as 5 grams of licorice product or 100 mg of glycyrrhizin per day can cause serious adverse effects.
Interactions
Médicaments
Antihypertensive: moderate interaction
Taking licorice at high doses for a long period can lead to an increase in blood pressure, thereby reducing the effectiveness of the medication. Warning - monitor blood pressure when high-dose licorice preparations are taken for more than 2 weeks.
Antiplatelet agents/Anticoagulant: weak interaction
Licorice has been reported to have an anticoagulant effect, so large amounts should be avoided in patients taking any form of anticoagulant medication.
Corticosteroid: low interaction
Case reports suggest that concomitant use of licorice and oral corticosteroids, such as hydrocortisone, may prolong their activity and increase blood levels of corticosteroids.
Diuretics: low interaction
Excessive licorice use could worsen diuretic-induced potassium loss. Initiating potassium supplementation or increasing the potassium supplement dose may be necessary in some patients.
Midazolam: moderate interaction
In humans, glycyrrhizin appears to moderately induce midazolam metabolism.nnGlycyrrhizin should be used with caution in people taking midazolam.
Precautions
Breastfeeding: avoid
Insufficient data.
Hormone-sensitive disease: avoid
Licorice may have estrogenic effects. Women with hormone-sensitive conditions should avoid using licorice. Some of these conditions include breast cancer, uterine cancer, ovarian cancer, endometriosis, and uterine fibroids.
Child: avoid
Use in children and adolescents under 18 years of age has not been established due to a lack of adequate data.
Contraindications
Hypertension: contraindicated
The mineralocorticoid effects of licorice may increase blood pressure. Patients with hypertension should avoid consuming excessive amounts of licorice.
Renal impairment: contraindicated
The mineralocorticoid effects of licorice may worsen renal function.
Pregnant women: contraindicated
Licorice has abortifacient, estrogenic, and steroidal effects. It can also cause uterine stimulation. High consumption of licorice, equivalent to 500 mg of glycyrrhizin per week (about 250 grams of licorice per week) during pregnancy, appears to increase the risk of preterm delivery.
Hypertension: contraindicated
Licorice-induced hypokalemia can worsen hypertension. The mineralocorticoid effects of licorice can cause hypokalemia.
Hypokalemia: contraindicated
The mineralocorticoid effects of licorice can decrease serum potassium levels and exacerbate hypokalemia.
