DGL Licorice: Deglycyrrhizinated Extract & Gastric Mucosal Healing
Deglycyrrhizinated licorice (DGL) is a modified extract of licorice root with the glycyrrhizin compound removed—the extraction that caused sodium retention and hypertension in traditional licorice preparations. This processing innovation has created a remarkably safe mucosal-protective agent with genuine clinical evidence for ulcer support. Among herbal gastric protectants, DGL stands out for having actual randomized controlled trial data demonstrating benefit.
Source & Chemical Processing
Licorice root (Glycyrrhiza glabra) is processed to remove glycyrrhizin (~5-7% of whole root), the compound responsible for mineralocorticoid effects and hypertension risk. The remaining deglycyrrhizinated extract retains other active constituents—particularly flavonoids (glabrol, licoricidin), chalcones, and polyphenolic compounds—that possess anti-inflammatory and mucosal-protective properties.
This selective removal makes DGL distinct from traditional licorice—it provides potential GI benefits while eliminating systemic side effects. This distinction is critical for understanding why DGL has different clinical applications than whole licorice root.
Mechanisms of Mucosal Protection
DGL operates through mechanisms distinct from simple mechanical coating:
- Gastric mucus enhancement: Increases gastric mucus viscosity and thickness, improving the protective mucus layer over gastric epithelium.
- Prostaglandin simulation: Stimulates prostaglandin-like effects in gastric tissue, enhancing mucosal blood flow and supporting epithelial cell integrity without systemic hormonal effects.
- Growth factor upregulation: May enhance growth factor (particularly EGF and HGF) expression in gastric mucosa, supporting epithelial repair processes.
- Anti-inflammatory modulation: Reduces TNF-α, IL-6, and other inflammatory cytokines in gastric tissue, addressing underlying inflammatory pathology.
- Ulcer-associated bacteria suppression: In vitro evidence suggests DGL may inhibit Helicobacter pylori growth, though clinical relevance remains debated.
- Antispasmodic effects: May reduce gastric smooth muscle contraction, reducing ulcer-related discomfort.
The combination of protective (mucus/prostaglandin) and regenerative (growth factor) mechanisms positions DGL more as a healing agent than as a simple coating supplement.
Clinical Evidence: Strongest Among Herbal Gastric Protectants
Gastric ulcer healing: This is DGL's strongest indication. Multiple RCTs (primarily European studies from the 1970s-1990s) demonstrate DGL accelerates gastric ulcer healing compared to placebo, with efficacy comparable to H2-receptor antagonists (cimetidine) in some trials. Typical dosing in studies was 750 mg 2-3 times daily for 4-8 weeks, with ulcer healing rates of 60-80% versus 45-60% in placebo groups.
Duodenal ulcer healing: Similar evidence base to gastric ulcers. DGL demonstrates benefit for healing and symptom relief, though evidence is somewhat more limited than for gastric ulcers.
Ulcer prevention (NSAID-related): Preliminary evidence suggests DGL may reduce NSAID-induced ulcer incidence when taken prophylactically with NSAIDs, though high-quality prevention trials are limited.
Gastroesophageal reflux disease (GERD): Anecdotal use is common, but controlled trials specifically testing DGL in GERD are sparse. The herb is often combined with other agents in reflux formulations, making efficacy attribution difficult.
Inflammatory bowel disease: Minimal research. A few small trials examined DGL in UC; modest benefit was reported, but evidence is too limited to recommend.
Dosing & Clinical Protocols
Standard clinical dosing is 750-1500 mg 2-3 times daily, typically taken 15-30 minutes before meals to allow contact with gastric mucosa before food. Most efficacy trials used 2250-4500 mg daily (typically 750 mg 3x daily) for 4-8 weeks before assessing healing.
Critical: DGL must be allowed to dissolve slowly in the mouth or taken with minimal water; this allows prolonged contact with esophageal and gastric mucosa. Some formulations are chewable specifically for this reason.
Duration matters: Most trials required 4+ weeks of consistent DGL use to achieve significant ulcer healing. Symptomatic relief may occur within 1-2 weeks, but mucosal healing requires sustained treatment.
Forms & Bioavailability
DGL is available as chewable tablets, capsules, and powder. Chewable forms are preferred as they allow prolonged mucosal contact. Capsule forms offer convenience but reduced local mucosal exposure.
Bioavailability of DGL flavonoids is modest (~10-20% systemic absorption); however, most therapeutic effects are local to the gastric mucosa, not systemic. The low bioavailability is actually favorable—reduced systemic absorption means fewer drug-drug interactions.
Safety Profile: Exceptional
DGL is among the safest herbal supplements, with essentially no significant adverse events reported even at high doses. Reported side effects are minimal and mild:
- Rare GI effects (bloating, constipation) at very high doses
- Minimal allergic reactions in sensitive individuals
Critical safety advantage over whole licorice: Because glycyrrhizin is removed, DGL does NOT cause sodium retention, potassium depletion, or hypertension—eliminating the primary safety concerns of traditional licorice. This is a major distinction.
Specific contraindications & cautions:
- None absolute. DGL has no documented contraindications even in special populations.
- Drug interactions: Minimal. DGL has virtually no systemic absorption, so medication interactions are exceedingly rare.
- Pregnancy & lactation: Generally considered safe; long traditional and modern use without adverse effects.
- Licorice allergy: Those with known licorice allergies should still exercise caution, though cross-reactivity with DGL (flavonoid-based) versus whole licorice (glycyrrhizin-based) has not been established.
DGL's safety profile is genuinely exceptional—it is one of the safest herbal supplements for chronic use.
DGL vs. Standard Acid Suppression (PPI/H2 Blockers)
A critical distinction: DGL does not suppress stomach acid like proton pump inhibitors (PPIs) or H2 blockers. Instead, it enhances mucosal protective mechanisms. In some trials, DGL demonstrated healing rates similar to cimetidine (an H2 blocker), suggesting different mechanisms can achieve similar ulcer healing outcomes.
For most modern ulcer management, particularly H. pylori-infected ulcers, acid suppression plus eradication therapy is standard. However, DGL may have a role in:
- NSAID-related ulcer prevention
- Adjunctive support during ulcer healing
- Prevention of ulcer recurrence after acid suppression therapy
- Functional dyspepsia with ulcer-like symptoms (nonulcer dyspepsia)
Who Should Consider DGL
Ideal candidates are those with documented gastric or duodenal ulcer disease seeking adjunctive or primary herbal support, individuals with NSAID-related ulcer history seeking prevention, and those with reflux-related gastritis. Because DGL is exceptionally safe, it is reasonable to add to standard medical therapy without risk of interaction.
Who May Benefit Most
DGL shows strongest evidence in gastric ulcer disease. Those with duodenal ulcers, functional dyspepsia, or GERD-related discomfort may see modest benefit but with weaker evidence. Individuals preferring herbal approaches or seeking to reduce PPI dependency have reasonable evidence for trial use.
The Bottom Line
Deglycyrrhizinated licorice represents one of the most evidence-supported herbal interventions for gastric ulcer healing, with RCT data demonstrating efficacy comparable to some pharmaceutical agents. Its mechanisms address mucosal protective and regenerative pathways distinct from acid suppression. Unlike whole licorice, DGL is exceptionally safe, with no documented contraindications or significant drug interactions. Standard dosing is 750 mg 3x daily for 4-8 weeks; chewable formulations are preferred for optimal mucosal contact. While most modern ulcer management relies on acid suppression, DGL may serve as adjunctive therapy or primary support in selected cases. Its safety profile supports chronic use without concern.
See also: Peptic Ulcer Healing: Pharmaceutical & Herbal Options Compared | NSAID-Induced Ulcer Prevention Strategies | Gastric Mucosal Protection: Evidence-Based Approaches
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This profile is for educational purposes only and does not constitute medical advice. Individuals with documented peptic ulcer disease should work with a healthcare provider to establish appropriate treatment, which may include DGL as adjunctive support but should not substitute for proven acid-suppression therapy or H. pylori eradication when indicated.
DrBayer.com Medical Review Team