DGL is licorice with most of the blood-pressure-raising compound removed, leaving plant compounds that soothe the mouth, stomach, and gut lining. The best evidence supports healing recurrent mouth ulcers, with more limited support for indigestion and stomach-ulcer healing. It works by strengthening the gut's own defenses rather than blocking stomach acid. The main safety concern is product quality. (Full Review)

Protocol

Standard Chewable

1–2 tablets before meals

~380–400 mg each, chewed ~20 min before meals, up to 3×/day

Ulcer-Healing

760 mg 3×/day

Before meals for several weeks

Standardized Extract

75 mg 2×/day

~150 mg/day for H. pylori suppression

Time to effect

Canker Sores

4–8 days

Healing of recurrent mouth ulcers

Indigestion

1–2 weeks

Symptom relief for functional dyspepsia

Ulcer Healing

Several weeks

Gastric and duodenal ulcers

Benefits

High: Recurrent canker sore relief

Medium: Functional indigestion symptom relief; gastric and duodenal ulcer healing

Low: Acid reflux symptom relief; Helicobacter pylori suppression; protection against NSAID-related stomach damage

Speculative: Reduced reliance on long-term acid-suppressing drugs; systemic antioxidant and anti-inflammatory effects

Contraindications

Uncontrolled hypertension (>140/90 mmHg)

Heart failure (NYHA class III–IV)

Chronic kidney disease (eGFR <60)

Documented hypokalemia (<3.5 mmol/L)

Primary aldosteronism

Pregnancy

Hormone-sensitive cancers

Key Interactions

Antihypertensive drugs (ACE inhibitors, angiotensin-receptor blockers, calcium-channel blockers)

Diuretics (thiazides, loop diuretics: hydrochlorothiazide, furosemide)

Digoxin

Corticosteroids (prednisone)

Warfarin and other narrow-safety-margin drugs

Stimulant laxatives, non-prescription diuretics

Other licorice- or glycyrrhizin-containing supplements

Risk & Side Effects

High: Pseudohyperaldosteronism from residual glycyrrhizin

Medium: Estrogen-like hormonal activity

Low: Mild gastrointestinal upset; additive potassium loss with certain medications

Speculative: Pregnancy and preterm-birth concerns; unknown very-long-term safety of concentrated flavonoid extracts

Monitoring

Marker	Target	Why
Blood pressure	<120/80 mmHg	Detect glycyrrhizin-related rise in pressure
Serum potassium	4.0–4.5 mmol/L	Detect glycyrrhizin-related potassium loss
Renin activity & aldosterone	Within lab reference	Confirm pseudohyperaldosteronism if pressure rises or potassium falls
H. pylori stool antigen / breath test	Negative	Confirm eradication when used for H. pylori

Cadence: Baseline, then recheck blood pressure and potassium after 2–4 weeks of regular use; every few weeks for those on interacting drugs or higher doses

Qualitative Assessment

Frequency and intensity of heartburn or regurgitation
Post-meal fullness, bloating, and upper-abdominal pain
Canker-sore frequency, size, and healing time
Overall digestive comfort and, indirectly, sleep quality when nighttime reflux improves

DGL for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment