DGL Licorice: Heartburn, Stomach, and Digestive System, What the Research Says

Licorice root, also known as licorice, is one of the oldest herbs in traditional medicine. Physicians in ancient Egypt, Greece, and Chinese medicine used it to soothe the stomach and throat thousands of years ago. But this plant has a modern and proven problem: the compound that gives licorice its characteristic sweet taste, glycyrrhizin, raises blood pressure, lowers potassium levels in the body, and in high doses can cause dangerous cardiac arrhythmias.

The solution to this problem is DGL licorice, an acronym for Deglycyrrhizinated Licorice, meaning licorice that has undergone a process to remove the glycyrrhizin. The result is a supplement that retains the plant compounds that soothe the gastrointestinal lining, but without the cardiovascular risk of whole licorice. In our evidence rating, DGL licorice receives an orange rating, there is reasonable but not strong evidence, mainly for symptomatic relief and not for a cure. In this article, we will separate what the research actually supports from the hype, and explain exactly who DGL is suitable for and who it is not.

What is DGL Licorice?

DGL licorice is a supplement derived from the root of the plant Glycyrrhiza glabra, after processing that removes most of the glycyrrhizin. The accepted definition is a supplement containing less than 3% glycyrrhizin, and usually much less. Here are the important characteristics to know:

• Without the danger of whole licorice: Removing the glycyrrhizin neutralizes the effect on blood pressure and potassium, making DGL a much safer form for regular use.
• Preserves the flavonoids: Plant compounds like glabridin and liquiritin, which are thought to be responsible for the soothing and protective effect on the stomach and esophageal lining, remain in the supplement.
• Usually chewed, not swallowed: Some preparations are made as chewable tablets, based on the assumption that saliva helps the compounds act directly on the esophageal and stomach lining.
• Not a medication: DGL is a dietary supplement, not a substitute for heartburn medications or for medical evaluation of persistent abdominal pain.

The Connection to the Digestive System: A Mechanism of Mucosal Protection

Unlike acid-suppressing medications like omeprazole, which reduce acid production in the stomach, the hypothesis for DGL is that it works through a completely different mechanism: strengthening and protecting the mucus layer that shields the gastrointestinal lining.

The idea is that DGL encourages the mucosal cells to secrete more protective mucus and relies less on acid suppression. A thicker, healthier mucus layer acts as a barrier against stomach acid, and thus may alleviate the burning sensation and give irritated tissue time to heal. Another proposed mechanism is local anti-inflammatory activity of the flavonoids, which may soothe mucosal irritation.

It is important to emphasize: this mechanism is still being studied, and part of it is based on laboratory studies and biological plausibility rather than full clinical proof in humans. This is one of the reasons for the orange rating rather than green.

Current Evidence

Study 1: Licorice Extract for Functional Dyspepsia from 2012

The most significant modern study on the subject is a randomized, double-blind, controlled trial by Raveendra and colleagues, published in the journal Evidence-Based Complementary and Alternative Medicine. The researchers, from a research center in Bangalore, India, examined a licorice extract called GutGard (an extract with low glycyrrhizin levels) in 50 patients with functional dyspepsia, meaning recurrent upper abdominal discomfort and pain without a structural cause. Participants received 75 milligrams twice daily or a placebo for 30 days. The result: the extract group showed a significant reduction in the total symptom score by day 15 and day 30 compared to placebo, as well as improvement in the Nepean dyspepsia index and overall efficacy assessment. The supplement was found to be safe and well-tolerated. This is a relatively small study, but it is the highest quality human evidence available today.

Study 2: Comparison to Medications in Preventing Gastric Ulcers from 1985

An older study published in the journal Gut, by Morgan and colleagues, compared a DGL preparation called Caved-S to the drug cimetidine (an H2 blocker) in preventing the recurrence of gastric ulcers over two years. The result was that Caved-S was equally effective as cimetidine in preventing ulcer recurrence. This is an interesting finding, but it should be remembered that it is from 1985, conducted before the era of proton pump inhibitors and antibiotic treatment against the bacterium H. pylori, which is now recognized as the cause of most gastric ulcers.

Study 3: DGL in Duodenal Ulcers from 1975

An early endoscopic review by Larkworthy and Holgate, published in the journal The Practitioner, followed 32 patients with chronic duodenal ulcers treated with DGL. The researchers reported improvement and healing in some patients. This is an old and small study, without a modern control group, so its value is limited, but it is part of the historical basis for using DGL for digestive issues.

What About Heartburn, Reflux, and True Ulcers?

Here it is important to be honest about the limitations of DGL. Many people try it for heartburn and reflux symptoms (GERD), and the evidence for this is mainly anecdotal and based on the theoretical mechanism of mucosal protection, rather than large, controlled studies specific to GERD. It may alleviate mild discomfort in some people, but it is not a substitute for medication in cases of severe or recurrent reflux.

Regarding ulcers: if in the past licorice was considered a treatment for ulcers, medical understanding has completely changed. Today it is known that most gastric and duodenal ulcers are caused by the bacterium H. pylori or by the use of anti-inflammatory drugs (NSAIDs). A true ulcer requires medical diagnosis, and usually specific antibiotic treatment or discontinuation of the causative drug. DGL does not eliminate the bacterium and does not heal an ulcer, so it must not replace medical evaluation.

Should You Start DGL Licorice?

DGL licorice is considered relatively safe, but there are rules and reservations that must be known:

• DGL only, not whole licorice: This is the critical point. Whole licorice or licorice extract with glycyrrhizin raises blood pressure, lowers potassium, and can cause a condition called pseudo-hyperaldosteronism. The FDA warns that regular consumption of whole licorice, especially over age 40, can cause arrhythmias and increased blood pressure. Only the glycyrrhizin-free form, DGL, neutralizes this risk.
• Persistent symptoms = medical check-up: Persistent upper abdominal pain, frequent heartburn, weight loss, difficulty swallowing, or blood in the stool require a visit to a doctor, among other things to rule out H. pylori, an ulcer, or a more serious problem. Do not use DGL to delay evaluation.
• Pregnancy and breastfeeding: There is insufficient safety data, and it is recommended to avoid without medical advice.
• Combination with medications: Anyone taking medications for the heart, blood pressure, or diuretics should consult a doctor or pharmacist, even with DGL, and certainly avoid whole licorice.
• Short-term supplement: DGL is mainly suitable for symptomatic and short-term use, not as a long-term regular treatment that replaces diagnosis.

What to Take Away from the Research?

1. If you are trying DGL, make sure it is the glycyrrhizin-free form. Look explicitly for the wording DGL or Deglycyrrhizinated on the packaging, and avoid regular licorice extracts for regular use.
2. A common dosage is one or two chewable tablets (about 300-400 milligrams) before meals, according to the manufacturer's instructions. Start with a low dose and check your response.
3. Use it for relief, not for diagnosis. If heartburn or discomfort persists beyond a few weeks, do not continue self-treating, see a doctor.
4. If you have high blood pressure or heart disease, stick to DGL only and consult a doctor before starting any type of licorice supplement.
5. Check its suitability for your goals: Not sure if DGL is right for you? Try our personal supplement selector that matches supplements for digestive health by gender, age, and goals.

You can purchase DGL licorice on iHerb, look explicitly for a product marked DGL or Deglycyrrhizinated, not a regular licorice extract.

The Broader Perspective

DGL licorice is a nice example of an important principle in the world of supplements: sometimes a traditional herbal remedy undergoes an engineering improvement that leaves the benefit but removes the danger. Removing the glycyrrhizin turned a plant problematic for the heart and blood vessels into a reasonable and relatively inexpensive supplement for relieving digestive discomfort. But that same honesty requires recognizing the limitations: the evidence is moderate, the effect is symptomatic and not curative, and DGL is not a competitor to medications in true cases of severe reflux, ulcers, or H. pylori infection.

If your stomach is occasionally sensitive and you are looking for a gentle herbal option for short-term use, DGL is a logical and safe choice, provided it is the correct form. But the most important rule remains the same: persistent digestive symptoms are not a condition for self-treatment, but a sign to see a doctor.

References:
Raveendra KR, et al. An Extract of Glycyrrhiza glabra (GutGard) Alleviates Symptoms of Functional Dyspepsia: A Randomized, Double-Blind, Placebo-Controlled Study. Evidence-Based Complementary and Alternative Medicine, 2012
Morgan AG, et al. Comparison between Caved-S and cimetidine in the prevention of symptomatic gastric ulcer recurrence. Gut, 1985
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