DGL Licorice: The Demulcent Backed by Old-School Heartburn Trials

DGL is one of those quiet workhorses of traditional herbalism — not flashy, not trending, but stubbornly useful for the kind of upper-GI complaints that bring people to a pharmacy at 11pm. It’s licorice root, but with the compound responsible for licorice’s blood-pressure problem (glycyrrhizin) deliberately stripped out. What’s left is the demulcent fraction: the mucilage-supporting, mucin-encouraging part that old-school clinicians and a handful of mid-century European trials kept circling back to for heartburn, functional dyspepsia, and ulcer recovery. The evidence is modest. The mechanism is plausible. And used realistically, alongside — not in place of — whatever your doctor has prescribed, it earns a quiet spot in a sensible gut-comfort routine.

The short answer

DGL — deglycyrrhizinated licorice — is licorice root (Glycyrrhiza glabra) that has been processed to remove most of the glycyrrhizin, the compound responsible for licorice’s well-known blood-pressure and potassium side effects. What’s left is a chewable, mucilage-rich extract used traditionally to soothe the lining of the stomach and esophagus. The strongest evidence sits with functional dyspepsia (chronic upper-abdominal discomfort without a clear structural cause) and as an adjunct in older ulcer-healing protocols. The weakest evidence sits with claims you’ll see online about “leaky gut” reversal — that’s a mechanistic hope, not a clinical conclusion.

If you’ve been prescribed a proton-pump inhibitor (PPI) or H2 blocker, DGL is not a replacement. It’s a complementary tool that some people use to take the edge off post-meal burning, to support a stepped-down acid-suppression plan under medical supervision, or simply to round out a broader gut-comfort routine.

Why “deglycyrrhizinated” matters

Regular licorice root contains glycyrrhizin (also called glycyrrhizic acid), a saponin that — once it’s metabolized in the body to glycyrrhetinic acid — inhibits an enzyme called 11β-hydroxysteroid dehydrogenase type 2. The cascade that follows is well documented in clinical literature: cortisol overstimulates mineralocorticoid receptors, the kidneys retain sodium, potassium gets dumped, and blood pressure climbs. In some people this happens at surprisingly modest intakes. People taking diuretics, people with hypertension, and people sensitive to electrolyte shifts are particularly vulnerable.

Deglycyrrhizination strips out the bulk of that glycyrrhizin — standardized DGL extracts typically contain less than 2% residual — while preserving the polysaccharides, flavonoids (liquiritin, liquiritigenin, isoliquiritin), and other phytochemicals that drive the demulcent action. The trade-off is real: you lose the systemic effects (the cortisol-modulating actions sometimes pursued for adrenal-fatigue protocols) but you also lose the side-effect profile that makes regular licorice a poor candidate for daily, long-term GI use. For a stomach-comfort tool, that’s the right trade.

If you’re reading a label and it just says “licorice root extract” without the “DGL” or “deglycyrrhizinated” designation, assume it contains glycyrrhizin until proven otherwise — and don’t take it daily without checking with your provider.

How DGL works

The proposed mechanisms for DGL’s upper-GI effects are physiologically reasonable rather than miraculous:

• Mucin production: animal and tissue studies suggest DGL may encourage the goblet cells lining the stomach to secrete more protective mucin, increasing the thickness of the gel barrier that separates stomach acid from the underlying epithelium.
• Prostaglandin support: licorice flavonoids appear to support local prostaglandin synthesis in the gastric mucosa — the same prostaglandins that maintain blood flow to the lining and stimulate bicarbonate secretion. This is the same pathway that NSAIDs inhibit, which is part of why NSAID-related ulcers are a clinical concern.
• Direct demulcent action: the polysaccharide fraction forms a soothing film on irritated mucosal tissue, similar to slippery elm or marshmallow root, though chemically distinct.
• Modulation of H. pylori adherence: in vitro work has suggested certain licorice flavonoids may interfere with Helicobacter pylori binding to gastric tissue. This is preliminary and not a substitute for triple-therapy eradication where indicated.

None of these mechanisms involve suppressing acid production the way a PPI does. DGL doesn’t turn off your acid pump; it supports the lining that has to deal with acid every day. That’s a meaningful distinction when you’re thinking about how to fit it into a larger plan.

The evidence by condition

Honest framing matters here. Licorice and its derivatives have been studied since the 1960s, but the trials are mostly small, mostly older, and mostly conducted before modern endoscopic methods became standard. Limited but encouraging research is the fairest summary.

Functional dyspepsia (the strongest signal). A 2012 randomized, double-blind, placebo-controlled trial by Raveendra and colleagues studied a standardized licorice root extract in 50 adults with functional dyspepsia over 30 days. The treatment group reported meaningful reductions in symptom severity (post-meal fullness, early satiety, epigastric burning) compared to placebo. The product studied was an extract somewhat different from a classic chewable DGL tablet, but the active fraction is closely related, and it’s one of the more methodologically clean modern licorice trials available.

Peptic ulcer healing (the older literature). Several mid-century European trials — particularly through the 1970s and early 1980s — compared chewable DGL preparations against cimetidine (a then-standard H2 blocker) for ulcer healing. Results were mixed; some trials reported comparable healing rates over 8–12 weeks, others found cimetidine modestly superior. The trials predate H. pylori’s discovery as the primary ulcer cause, so the population studied likely included many cases that today would be treated with antibiotic eradication. The conservative read is that DGL may support ulcer healing in some contexts but should not be the primary intervention.

GERD and reflux (limited evidence). Direct trial data for DGL in classical GERD is thin. Some integrative-medicine references cite open-label use for symptom relief, but well-controlled RCTs specifically in GERD are scarce. What exists is mostly extrapolation from the dyspepsia and ulcer literature plus mechanistic plausibility. If you have GERD and you’re weighing options, our overview on probiotics for acid reflux covers the microbial angle, and heartburn and probiotics goes deeper on practical layering.

H. pylori adjunct. A 2017 study by Asha and colleagues examined licorice extract as an adjunct to standard triple therapy for H. pylori eradication and reported modestly improved outcomes. Like other adjunct studies, this is supporting evidence rather than standalone evidence — the standard antibiotic regimen remains the basis of treatment.

“Leaky gut.” You’ll see DGL marketed for intestinal permeability, but the direct clinical evidence is essentially absent. The mechanism (mucin support, mucosal defense) is consistent with what people mean when they discuss the gut lining, but extrapolating from upper-GI demulcent action to systemic intestinal-barrier repair is a leap. Our leaky gut overview covers what the evidence actually says about the broader concept.

Dosing and how to take it

The form matters more than people expect. Most of the trial-supported DGL data uses chewable tablets, not capsules or powders — and there’s a reason for that. The saliva-activation step appears to be functionally important: chewing the tablet mixes the demulcent components with saliva, forming the soothing slurry that then coats the esophagus and stomach on the way down. Swallowing an intact capsule bypasses that mixing step and may reduce the upper-GI effect, even if the same dose lands in the stomach.

Typical dose: 380–760 mg chewed thoroughly about 20 minutes before meals, two to three times daily. Many people start at the low end (one 380 mg tablet before the two heaviest meals of the day) and adjust upward if tolerated and helpful. Some integrative practitioners use higher doses for short-term ulcer-recovery protocols; that’s a conversation to have with a clinician, not something to escalate to on your own.

Timing: the 20-minute window before meals is traditional and lines up with the mechanistic logic — you want the demulcent layer in place before stomach activity ramps up. Taking DGL after a meal is sometimes done for breakthrough symptoms but isn’t the canonical schedule.

Duration: for functional dyspepsia or general comfort, a 4–8 week trial is reasonable. If you haven’t noticed a useful change by 8 weeks of consistent use, it probably isn’t going to be the right tool for you. For ulcer-recovery protocols under clinical supervision, courses of 8–16 weeks have historical precedent.

Safety and who should skip it

DGL has a generally favorable safety profile precisely because the troublesome compound has been removed. The cautions are still worth understanding.

• Residual glycyrrhizin. Standardized DGL contains less than 2% glycyrrhizin, but if you stack multiple licorice-containing products (some cough drops, some bedtime teas, some “adrenal support” blends contain whole licorice) the residuals can add up. Read labels.
• Drug interactions. Even the small residual glycyrrhizin warrants caution with diuretics, corticosteroids, digoxin, and certain blood-pressure medications. Talk with your pharmacist if you take any of these daily.
• Pregnancy caution. Whole licorice has been associated with adverse pregnancy outcomes in observational studies (preterm birth, neurodevelopmental signals at higher exposures). DGL has a much lower glycyrrhizin load and a different risk profile, but the conservative default is to avoid DGL during pregnancy unless cleared by a knowledgeable provider. The demulcent benefit is rarely essential during pregnancy and safer alternatives exist.
• Breastfeeding. Data are limited; the same conservative default applies.
• Existing hypertension or kidney disease. Reasonable for most people on standardized DGL but worth a check-in with your provider before regular daily use.
• Children. Not typically used in pediatric protocols outside qualified herbalist supervision.

An explicit note: DGL is not a replacement for a PPI or H2 blocker if your doctor has prescribed one. If you’re hoping to step down from acid-suppression therapy, that’s a conversation with your prescriber, not a unilateral decision based on a supplement bottle.

DGL vs. other demulcents

DGL sits in a small but useful family of plant-based demulcents that all share the same general logic — soothing coatings, mucosal support — while differing in chemistry, traditional indications, and best-fit use cases.

• Slippery elm: a powerful mucilage from the inner bark of Ulmus rubra, often used as a powder stirred into water. Strongest traditional association with the throat, esophagus, and IBS. Important medication-spacing rule (1 hour away from prescriptions). Sustainability concern with wild-harvested bark.
• Marshmallow root (Althaea officinalis): another mucilaginous demulcent with a long traditional history. Very similar in mechanism to slippery elm. Often used interchangeably or in combination, sometimes preferred for urinary-tract applications.
• Aloe vera (inner-leaf gel): contains polysaccharides with demulcent properties. Some small trials in GERD show promise. Distinct from aloe latex (which is a laxative and shouldn’t be confused with the inner-leaf gel preparation).
• Mastic gum: not a classical demulcent — it’s a tree resin from Pistacia lentiscus that works on the stomach lining through different mechanisms (microbial environment, mucosal support). Often paired with DGL or slippery elm because it complements rather than duplicates them.

Where DGL stands out: it’s the only one of this group with a chewable, before-meals delivery format that lines it up specifically with eating-related symptoms. It also has more direct clinical-trial data in functional dyspepsia than slippery elm or marshmallow root. For pure throat or IBS work, slippery elm tends to be the better pick. For upper-GI burning around meals, DGL is often the more targeted choice.

Who should skip DGL

The shortlist of people who should probably leave DGL alone:

• Anyone pregnant or trying to conceive, absent specific provider guidance.
• Anyone breastfeeding, on the same conservative grounds.
• People on diuretics, digoxin, corticosteroids, or multiple antihypertensives without clearing it with a pharmacist.
• People with poorly controlled hypertension, hypokalemia, or significant kidney disease.
• People who’ve been prescribed acid-suppression therapy and are hoping DGL can substitute — that’s a clinician conversation, not a substitution.
• People with red-flag GI symptoms (unintentional weight loss, persistent vomiting, swallowing difficulty, black stools, blood in stool, anemia of unclear cause) — those need evaluation, not a supplement.

A practical routine

For someone with garden-variety post-meal upper-abdominal discomfort — not severe, not red-flag, not on prescription acid suppression — a reasonable starting routine looks something like this:

• Two chewable DGL tablets per day (380 mg each), one chewed 20 minutes before lunch and one chewed 20 minutes before dinner. Chew thoroughly — the saliva mixing matters.
• A 4-week trial before deciding whether it’s helping. Symptom diaries help here; memory is unreliable for slow-shifting GI symptoms.
• Layer with a probiotic protocol for the lower-GI side of the picture if relevant. DGL handles the upper-GI demulcent piece; a multi-strain probiotic handles a different part of the digestive tract entirely.
• Pair with the obvious lifestyle pieces — smaller meals, finishing eating 3 hours before bed, reducing alcohol, identifying personal trigger foods. Supplements don’t compensate for ignoring the basics.
• Don’t stack licorice. If your evening tea or cough lozenge contains whole licorice, those count toward your daily glycyrrhizin load.
• Reassess at 8 weeks. If it’s working, you can continue. If it’s not, move on without sunk-cost commitment to the bottle.

If you’d like a broader gut-restoration plan around this, our 30-day gut reset walks through how dietary, microbial, and mucosal strategies fit together over a month. And if any of the terms here are unfamiliar, the gut health glossary defines them in plain English.

The bottom line

DGL is a sensible, evidence-grounded option for upper-GI comfort that fills a niche most modern supplement protocols ignore. It’s not a miracle herb, it’s not a PPI replacement, and it’s not a leaky-gut cure — but it’s a credible demulcent with real (if modest) trial support in functional dyspepsia, a long history of adjunctive use in ulcer recovery, and a safety profile that compares favorably against regular licorice precisely because the troublesome compound has been removed. The honest framing: limited but encouraging research, a plausible mechanism, a clear best-use scenario (chewed before meals, layered with a broader gut plan, not used in place of prescribed acid suppression), and a short list of people who should skip it. Used that way, it earns its place.