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Moderate evidenceGut health

Licorice Root

Whole licorice root containing glycyrrhizin reliably raises blood pressure and lowers potassium — this is the most robustly proven effect of the herb, and it is a harm, not a benefit. If you want licorice for digestive use, take the deglycyrrhizinated (DGL) form instead.

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What the science says

  • Glycyrrhizin raises blood pressure and causes hypokalemia — established and dose-dependent Strong evidence

    A systematic review and meta-analysis of licorice ingestion studies confirmed consistent increases in systolic blood pressure and decreases in serum potassium across trials. A 2024 randomized crossover trial found that even a low daily dose — about 100 mg glycyrrhizin, roughly 3 g of licorice confectionery — significantly suppressed renin and aldosterone and raised home-measured blood pressure in healthy young adults. The mechanism is well characterized: glycyrrhetinic acid inhibits 11-beta-hydroxysteroid dehydrogenase type 2, letting cortisol act on mineralocorticoid receptors.

  • DGL for dyspepsia and mouth ulcers is the plausible use, and it is the form without the risk Limited evidence

    Deglycyrrhizinated licorice removes over 95% of glycyrrhizin and therefore the blood-pressure effect. Small trials support DGL at 75-150 mg twice daily for functional dyspepsia symptoms and topical DGL patches for aphthous ulcers, but trials are few and small. See our separate DGL licorice entry — for gut use, DGL is the sensible choice.

  • Cough, sore throat and "adrenal support" claims are weakly supported Limited evidence

    Licorice is a traditional demulcent and there is modest trial evidence that licorice gargle reduces postoperative sore throat after intubation. The "adrenal fatigue" positioning — that licorice extends cortisol half-life and therefore supports tired adrenals — is a real pharmacological effect being sold as a benefit; sustained cortisol potentiation is exactly the mechanism that causes the hypertension and potassium loss.

Dosage & safety

Studied doseRegulatory guidance is the useful number here: the EU Scientific Committee on Food and WHO suggest keeping glycyrrhizin intake at or below roughly 100 mg/day, and the 2024 trial showed measurable cardiovascular effects even at that ceiling. Whole-root supplements often supply 400-500 mg of root per capsule with glycyrrhizin content unstated. Trials of licorice root as a medicine generally run 2-6 weeks and are not designed for chronic use. DGL is dosed at 380-760 mg chewed before meals in dyspepsia protocols.
SafetyPseudohyperaldosteronism is the defining risk: hypertension, hypokalemia, sodium and fluid retention, edema, muscle weakness, and — in published case reports — hypokalemic rhabdomyolysis, QT prolongation, arrhythmia, and hypertensive emergency. Cases have followed daily licorice candy consumption, not just supplements. The FDA has issued Halloween-season warnings about black licorice, noting that as little as roughly 2 ounces a day for two weeks has landed adults over 40 in hospital with arrhythmias. Contraindicated in hypertension, heart failure, kidney disease, liver disease, and hypokalemia. Dangerous interactions: additive potassium loss with thiazide and loop diuretics (raising digoxin toxicity risk), and it opposes antihypertensives. Avoid in pregnancy — higher glycyrrhizin intake in pregnancy has been associated with shorter gestation and adverse neurocognitive outcomes in offspring in Finnish cohort studies. Effects can persist for weeks after stopping.

How to take it

TimingTiming does not matter; total daily glycyrrhizin is what counts.
With food?Either way; DGL is chewed before meals in dyspepsia protocols.
Worth knowingCount licorice sweets and teas as well as capsules — the hospitalised cases in the literature came from confectionery, and effects can persist for weeks after stopping.

Interactions

With medications

  • thiazide and loop diuretics

    Both deplete potassium, and together they have caused severe hypokalaemia. do not combine

  • digoxin

    Licorice-induced low potassium sharply increases the risk of digoxin toxicity. avoid licorice entirely on digoxin

  • blood-pressure medication

    Licorice raises blood pressure and retains sodium, directly opposing treatment. avoid if you are treated for hypertension or heart failure

  • corticosteroids (prednisolone, hydrocortisone)

    Glycyrrhizin blocks the enzyme that inactivates cortisol, prolonging and amplifying steroid effects. avoid combining

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does licorice root raise blood pressure?

Yes: licorice root containing glycyrrhizin reliably raises blood pressure and lowers potassium (strong evidence). A 2024 trial found that even about 100 mg glycyrrhizin a day, roughly 3 g of licorice confectionery, raised blood pressure in healthy young adults.

How much licorice is safe per day?

The EU Scientific Committee on Food and WHO suggest keeping glycyrrhizin at or below roughly 100 mg/day, and measurable cardiovascular effects appeared even at that level. Count licorice sweets and teas as well as capsules, since hospitalised cases have followed daily licorice candy.

Is DGL licorice better for heartburn and indigestion?

For digestive use, deglycyrrhizinated licorice (DGL) is the sensible choice: it removes over 95% of glycyrrhizin and therefore the blood-pressure effect. Small trials support DGL for functional dyspepsia, but the evidence is limited.

Who should not take licorice root?

Whole licorice root is contraindicated in hypertension, heart failure, kidney disease, liver disease, low potassium and pregnancy. Do not combine it with thiazide or loop diuretics, digoxin, blood-pressure medication or corticosteroids, and note that effects can persist for weeks after stopping.

Scientific references

Where to buy

Nature's Answer, Licorice Root Fluid Extract, Alcohol-Free, 2,000 mg, 1 fl oz (30 ml)

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