DGL Licorice — Research Profile

Regular licorice contains glycyrrhizin, which inhibits cortisol metabolism and causes pseudo-aldosteronism (hypertension, fluid retention, low potassium). DGL has glycyrrhizin removed, eliminating these risks while retaining the gastroprotective compounds. Always use DGL for medicinal purposes, especially long-term.

Traditional teaching holds that chewing DGL tablets mixes them with saliva, which contains epidermal growth factor (EGF) that synergizes with DGL for mucosal repair. While this mechanism is debated, clinical studies typically used chewable forms. Swallowing DGL capsules may still provide benefit but chewable is the traditional recommendation.

Yes. DGL works by a completely different mechanism than PPIs. PPIs reduce acid production; DGL enhances mucosal defense. They are complementary, not conflicting. DGL may provide additional symptom relief and mucosal support while taking a PPI, and may support PPI tapering when appropriate under medical guidance.

Trials used different forms: a standardized flavonoid-rich extract (GutGard, 75 mg twice-daily capsules) for functional dyspepsia and chewable DGL tablets (Caved-S, six daily) for gastric ulcer. No head-to-head study identifies one best form. Chewable tablets are the traditional choice for direct upper-GI contact, while a standardized capsule delivers a defined, reproducible dose.

The best-supported benefit is relief of functional dyspepsia: GutGard 75 mg twice daily significantly reduced total symptom scores and improved the Nepean Dyspepsia Index versus placebo over 30 days. An older endoscopically controlled trial found the DGL preparation Caved-S healed benign gastric ulcers about as well as cimetidine (roughly 91% at 12 weeks), although cimetidine relieved night pain faster in the first two weeks. Evidence for other uses is limited.

There is no official recommended dose. In the functional dyspepsia RCT, standardized GutGard was taken as 75 mg twice daily (150 mg/day) for 30 days. The Caved-S ulcer regimen used six tablets daily during active treatment, reduced to two tablets twice daily for maintenance. Because amounts vary by product and goal, follow the specific label rather than a single fixed number.

The best time of day has not been directly compared in trials. The functional dyspepsia study simply dosed GutGard twice daily, and chewable DGL is traditionally taken around meals for upper-GI symptoms, but no study shows one schedule outperforms another. Choose a schedule you can keep to and that fits when your symptoms occur.

In the functional dyspepsia trial, GutGard was reported safe and well tolerated with no notable adverse effects over 30 days. Because DGL has most glycyrrhizin removed, it largely avoids the raised blood pressure, potassium loss, and irregular heartbeat that whole licorice can cause. However, a product still containing residual glycyrrhizin can produce those same effects, so the deglycyrrhizination quality matters.

The only medication interaction NCCIH names for licorice is with corticosteroids. Broader interactions trace to glycyrrhizin, which inhibits the renal enzyme 11-beta-hydroxysteroid dehydrogenase and thereby raises blood pressure and lowers potassium; on that basis Memorial Sloan Kettering's herb monograph flags that licorice may potentiate digoxin (cardiac glycoside) toxicity, worsen the hypokalemia caused by diuretics, and blunt antihypertensive drugs. Because DGL is processed to remove most glycyrrhizin, these risks are greatly reduced, but residual amounts vary by product, so anyone on those medications should check the glycyrrhizin content before use.

DGL is most relevant for adults with functional dyspepsia or a history of gastric ulcer who want a non-prescription option, based on the GutGard and Caved-S trials. People who want licorice's gut effects while avoiding its blood-pressure and potassium risks choose DGL specifically because the glycyrrhizin is removed. Safety in pregnancy is not established for DGL, so it is not a routine choice there.

Onset depends on the goal. In the functional dyspepsia trial of standardized GutGard (75 mg twice daily), total symptom scores were already significantly lower than placebo by day 15 and improved further by day 30. Structural ulcer healing is slower: the Caved-S DGL trial measured gastric-ulcer healing at 6 and 12 weeks (roughly 63% and 91%), so expect weeks rather than days.

NCCIH states that licorice with glycyrrhizin removed (DGL) might be safe when taken orally for up to about 4 months; safety beyond that is not established. Removing glycyrrhizin avoids the raised blood pressure, potassium loss, and irregular heartbeat linked to whole licorice, but residual glycyrrhizin varies by product. Clinical trials generally ran only 4 to 12 weeks, so daily use beyond a few months lacks direct trial support.

No upper limit has been established for DGL specifically. The main toxicity from licorice comes from glycyrrhizin, which even in modest amounts can raise blood pressure, lower potassium, and trigger irregular heartbeat; DGL is processed to strip out most of that compound, sharply reducing the risk. Because products differ in residual glycyrrhizin, large or prolonged doses of a poorly deglycyrrhizinated product could still produce those effects.

No trials have tested DGL stacked with other supplements, so added benefit or harm from combinations is unproven. DGL was studied on its own for functional dyspepsia (GutGard 150 mg/day) and for gastric-ulcer healing (Caved-S), not alongside other gut agents. The clearest caution is a product retaining meaningful glycyrrhizin, which could compound the potassium-lowering effects of other substances.

Confirm the product is genuinely deglycyrrhizinated, with glycyrrhizin reduced to a low residual, since that is what separates DGL from whole licorice and its blood-pressure and potassium risks. A standardized extract such as GutGard, used at 75 mg twice daily in the functional dyspepsia trial, lets you match a dose that was actually studied. Verify the label states the extract and per-serving amount rather than just 'licorice.'