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Limited evidenceGut health

DGL Licorice

Deglycyrrhizinated licorice removes the compound that raises blood pressure, which makes it far safer than whole licorice — but the efficacy evidence is mostly small trials from the 1970s-80s, largely superseded by acid suppression, plus a handful of modern trials of a different, flavonoid-standardised extract.

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What the science says

  • Relieves functional dyspepsia Moderate evidence

    The strongest modern data is a randomised, double-blind, placebo-controlled trial of a standardised Glycyrrhiza glabra extract (GutGard, 75 mg twice daily, n=50) reporting significant improvement in dyspepsia symptom scores at 30 days versus placebo. Note this is a flavonoid-standardised extract, not classic DGL chewables — the products are not interchangeable, and it is a single small trial.

  • Protects gastric mucosa against aspirin damage Limited evidence

    A 1979 crossover study found DGL significantly reduced aspirin-induced gastric mucosal damage measured by faecal blood loss in healthy volunteers. It is a mechanistically plausible mucosal protectant, but the study was small, is nearly 50 years old, and no modern trial has tested DGL against NSAID gastropathy alongside a PPI.

  • Heals peptic ulcers Limited evidence

    Trials from the 1970s-80s reported DGL comparable to then-standard therapies such as cimetidine for ulcer healing, but these are small, methodologically dated, pre-date the discovery of H. pylori, and have never been repeated. Peptic ulcer is now a diagnosable, curable condition — DGL should never substitute for H. pylori testing and eradication.

  • Treats reflux or heals 'leaky gut' Limited evidence

    These are marketing claims with no supporting RCTs. There are no controlled trials of DGL for GERD, and none for intestinal permeability outcomes in humans.

Dosage & safety

Studied doseClassic DGL: 380-760 mg of chewable tablets, chewed 20 minutes before meals, 2-3 times daily. Chewing is part of the traditional protocol because saliva is thought to contribute to the mechanism. Standardised flavonoid extract (GutGard): 75 mg twice daily, as used in the dyspepsia trial. Products should state glycyrrhizin content below 2% (ideally under 0.5%) to count as genuinely deglycyrrhizinated.
SafetyDGL's whole point is removing glycyrrhizin, which in whole licorice inhibits 11-beta-hydroxysteroid dehydrogenase type 2 and causes pseudoaldosteronism: hypertension, hypokalaemia, oedema, muscle weakness, arrhythmias and, in reported cases, rhabdomyolysis and cardiac arrest — with effects documented at intakes as low as ~100 mg glycyrrhizin/day over weeks. Properly deglycyrrhizinated products avoid this, but glycyrrhizin content is inconsistently verified across brands, so read the label and avoid products that only say 'licorice root'. Do not combine whole licorice with diuretics, digoxin, corticosteroids or antihypertensives, or use it if you have hypertension, heart failure, kidney disease, hypokalaemia or are pregnant (licorice intake in pregnancy is associated with shorter gestation and adverse neurocognitive outcomes in offspring). Even DGL should not be used to self-treat suspected ulcer or persistent dyspepsia without ruling out H. pylori and malignancy — alarm symptoms (weight loss, dysphagia, bleeding, anaemia, new symptoms over age 55) require endoscopy.

How to take it

TimingChewed about 20 minutes before meals, two or three times a day.
With food?Before food rather than with it.
Worth knowingIf the label says only 'licorice root' with no glycyrrhizin figure, it is not DGL and it carries the full blood-pressure and potassium risk.

Interactions

With medications

  • digoxin

    If the product still contains glycyrrhizin, the resulting potassium loss increases digoxin toxicity risk. only use a product with declared glycyrrhizin below 0.5%, or avoid entirely

  • thiazide and loop diuretics, and corticosteroids

    Residual glycyrrhizin adds to potassium loss and fluid retention. do not combine unless the label documents glycyrrhizin content

  • antihypertensives

    Glycyrrhizin raises blood pressure through pseudoaldosteronism and can work against blood-pressure medication. avoid whole licorice; check the glycyrrhizin figure on any DGL product

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

Frequently asked questions

Does DGL licorice help with acid reflux?

There are no controlled trials of DGL licorice for GERD, so the reflux claim is unsupported. The best modern DGL-related evidence is a single small trial of a flavonoid-standardised licorice extract for functional dyspepsia.

Is DGL licorice safe for blood pressure?

Properly deglycyrrhizinated DGL licorice removes glycyrrhizin, the compound that raises blood pressure and lowers potassium. Check the label: glycyrrhizin should be below 2%, ideally under 0.5% — a product saying only 'licorice root' carries the full risk.

Does DGL licorice heal stomach ulcers?

The evidence is limited to small 1970s-80s trials that predate the discovery of H. pylori. DGL licorice should never replace H. pylori testing and treatment, and persistent symptoms need medical assessment.

How do you take DGL licorice?

Chew 380-760 mg of DGL licorice tablets about 20 minutes before meals, two or three times daily. The flavonoid-standardised extract used in the dyspepsia trial was 75 mg twice daily.

Scientific references

Where to buy

Nature's Life, DGL Licorice Chewable, 380 mg, 100 Chewables

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