Deglycyrrhizinated Licorice (DGL)
Research reviewed: Up until 03/2026
Deglycyrrhizinated Licorice (DGL) (Glycyrrhiza glabra (deglycyrrhizinated extract)) is a dietary supplement with 7 published peer-reviewed studies involving 332 participants, researched for Gastric & Duodenal Ulcers, Dyspepsia & Functional GI, Mucosal Protection & Oral Health.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Gastric & Duodenal Ulcers
ModerateDyspepsia & Functional GI
ModerateMucosal Protection & Oral Health
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Gastric & Duodenal Ulcers
To evaluate DGL for gastric ulcer healing.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate DGL for gastric ulcer healing.
Dose
760 mg DGL chewable tablets three times daily before meals
Participants
100 patients with confirmed gastric ulcers
Duration
12 weeks
Results
DGL achieved 44% complete healing at 12 weeks vs 6% placebo. Significant reduction in ulcer size and symptom improvement in the DGL group.
How They Measured It
Endoscopic ulcer healing rate, symptom improvement
To compare DGL with cimetidine for duodenal ulcer healing.
Study Type
Randomised controlled trial
Purpose
To compare DGL with cimetidine for duodenal ulcer healing.
Dose
DGL 380 mg four times daily vs cimetidine 200 mg three times daily + 400 mg at bedtime
Participants
82 patients with duodenal ulcers
Duration
12 weeks + 2-year follow-up
Results
DGL and cimetidine showed comparable ulcer healing rates at 12 weeks (91% vs 92%). Two-year relapse rate was lower with DGL (36% vs 42%).
How They Measured It
Endoscopic ulcer healing, symptom resolution, relapse rate
To evaluate DGL on duodenal ulcer healing.
Study Type
Double-blind, placebo-controlled
Purpose
To evaluate DGL on duodenal ulcer healing.
Dose
DGL 380 mg chewable four times daily
Participants
40 patients with endoscopically confirmed duodenal ulcers
Duration
8 weeks
Results
DGL significantly accelerated duodenal ulcer healing compared to placebo. 78% healing in DGL group vs 34% placebo at 8 weeks.
How They Measured It
Endoscopic ulcer healing, ulcer size reduction
Dyspepsia & Functional GI
To evaluate DGL plus antacid for functional dyspepsia.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate DGL plus antacid for functional dyspepsia.
Dose
DGL 150 mg before meals + antacid as needed
Participants
50 patients with functional dyspepsia
Duration
4 weeks
Results
DGL + antacid significantly improved dyspepsia symptoms (epigastric pain, heartburn, nausea) compared to antacid alone.
How They Measured It
Dyspepsia symptom scores, quality of life
To evaluate DGL on GERD symptoms and esophageal mucosal healing.
Study Type
Open-label study
Purpose
To evaluate DGL on GERD symptoms and esophageal mucosal healing.
Dose
DGL 380 mg chewable tablets, three times daily
Participants
24 patients with symptomatic GERD
Duration
8 weeks
Results
DGL reduced heartburn frequency and severity scores. Endoscopic improvement was modest. Not as effective as PPIs for erosive esophagitis.
How They Measured It
GERD symptom questionnaire, endoscopic esophageal appearance
Mucosal Protection & Oral Health
To evaluate DGL for aphthous stomatitis (canker sores).
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate DGL for aphthous stomatitis (canker sores).
Dose
DGL 200 mg mouthwash (dissolved in warm water) four times daily
Participants
20 patients with recurrent aphthous ulcers
Duration
Until healing (max 14 days)
Results
DGL significantly accelerated healing of aphthous ulcers (50-75% reduction in healing time). Pain scores were significantly lower by day 1 in the DGL group.
How They Measured It
Healing time, pain VAS, lesion size
To evaluate DGL extract on gastric mucosal blood flow and mucus secretion.
Study Type
Randomised, controlled
Purpose
To evaluate DGL extract on gastric mucosal blood flow and mucus secretion.
Dose
DGL 380 mg
Participants
16 healthy volunteers
Duration
Single dose study
Results
DGL significantly increased gastric mucosal blood flow and mucus production. Effect was comparable to prostaglandin analog misoprostol.
How They Measured It
Gastric mucosal blood flow (laser Doppler), mucus thickness (biopsy)
Frequently Asked Questions
Common questions about Deglycyrrhizinated Licorice (DGL) research
There are currently 7 peer-reviewed studies on Deglycyrrhizinated Licorice (DGL) (Glycyrrhiza glabra (deglycyrrhizinated extract)), involving 332 total participants. Research covers Gastric ulcer support, Mucosal protection, Dyspepsia and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (7 human studies), and reported outcomes.
Deglycyrrhizinated Licorice (DGL) has been researched for: Gastric ulcer support, Mucosal protection, Dyspepsia, Oral health. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 7 out of 7 studies are human trials. Human trials carry more weight in our evidence scoring system.
