Supplement

DGL licorice (deglycyrrhizinated)

Herbs · Deglycyrrhizinated Licorice, DGL, Glycyrrhiza glabra, licorice root without glycyrrhizin, GutGard

DGL is licorice root from which the glycyrrhizin has largely been removed, that is, precisely the substance that makes blood pressure rise and potassium fall with licorice. DGL is marketed for heartburn, functional dyspepsia and stomach ulcers. The older placebo-controlled studies in ulcers found no benefit; newer double-blind studies with a single special extract show better results in dyspepsia and reflux.

What DGL licorice is

Licorice, Glycyrrhiza glabra, is the root from which licorice candy is also made. Its best-known constituent is glycyrrhizin. DGL stands for deglycyrrhizinated licorice, that is, licorice from which this substance has largely been removed. How much remains depends on the product; the extract GutGard, tested in newer studies, contains at most 3 percent glycyrrhizin and is standardized to flavonoids such as glabridin.

In the BK-Score, human evidence stands at 4 out of 10 points. This axis rates the state of knowledge, not the substance: there are quite a few studies, but the older ones are negative and the newer ones depend on a single extract.

Glycyrrhizin: why it is removed

In larger amounts, glycyrrhizin causes the body to retain sodium and lose potassium. The consequences can be high blood pressure, water retention and muscle weakness. The German Federal Institute for Risk Assessment therefore advises taking in less than 100 mg of glycyrrhizin per day and considers licorice with more than 200 mg of glycyrrhizin per 100 g problematic for regular consumption. The plant list of the German federal government and states therefore lists licorice root in List B, that is, with a recommended quantity limit.

DGL is meant to get around this problem. That only works if the residual content is actually low. For food supplements, it is not uniformly regulated and not always stated.

How it is supposed to work

DGL is marketed as protection for the lining of the stomach and esophagus and as a remedy against Helicobacter pylori. These effects come mainly from laboratory and animal experiments. In humans, what is mainly established is what DGL is no longer supposed to do: shift the mineral balance via glycyrrhizin.

What is well supported

Fewer reflux symptoms with one special extract. In a double-blind study with 200 participants, quality of life improved more under GutGard after 28 days than under placebo (p = 0.014), and heartburn and belching subsided faster.
Fewer dyspepsia symptoms with the same extract. In functional dyspepsia, symptom scores fell more on days 15 and 30 than under placebo.
Glycyrrhizin is the risk substance, not the root itself. The dangers of licorice for blood pressure and potassium are well described and tied to glycyrrhizin. The BfR names a clear limit.

What the studies show

Stomach ulcers: three negative studies from the 1970s

Bardhan and colleagues randomly assigned 96 patients with gastric ulcer to DGL or placebo. After four weeks, there was no difference in complete healing, in reduction of ulcer size or in symptoms. Engqvist and colleagues tested the DGL product Caved-S double-blind in a crossover in 38 patients with 47 ulcers and found no faster healing. Feldman and Gilat found no advantage over placebo after one month in 47 patients with duodenal ulcer.

Functional dyspepsia: GutGard

Raveendra and colleagues gave patients with functional dyspepsia, double-blind, 75 mg of GutGard twice daily or placebo for 30 days. Total symptoms and the quality-of-life index fell significantly more on days 15 and 30 than under placebo.

Reflux symptoms: GutGard

Raj and colleagues in Mumbai enrolled 200 people with reflux symptoms in a double-blind phase III study over 28 days. Under GutGard, quality of life was better at the end (p = 0.014), and heartburn and belching subsided earlier, heartburn from day 14.

Helicobacter pylori: GutGard

Puram and colleagues gave 107 infected people 150 mg of GutGard or placebo for 60 days. Afterwards, the stool antigen test was negative in 56 percent under GutGard and in 4 percent under placebo, and the breath test in 48 percent under GutGard. A standard eradication therapy was not part of the comparison; whether the bacterium had disappeared permanently remained open.

Where the data stop

Gastric and duodenal ulcers. The placebo-controlled studies found no benefit. Ulcers belong in medical treatment.
Transferability. All positive newer studies were conducted with GutGard. Whether other DGL products work the same way has not been studied.
Helicobacter. A single study with stool and breath tests does not replace a comparison with standard therapy.
Duration. The studies ran for four to eight weeks. Data on long-term use are lacking.

Status, approval and legal

DGL is sold in Germany as a food supplement. Licorice root is listed in the plant list of the German federal government and states as a food, including in food supplements, and at the same time as a medicinal substance in List B: because of the glycyrrhizin, a quantity limit is indicated. The EMA has an EU monograph on licorice root with traditional use in digestive complaints with burning and as an expectorant for cough; it concerns preparations of the regular root, not DGL. Food supplements may not be advertised for the treatment of diseases such as reflux or stomach ulcers.

Safety

In the studies with GutGard, the extract was well tolerated. The main risk of licorice, the effect of glycyrrhizin on blood pressure and potassium, is largely eliminated with DGL, but only if the residual content is low. Anyone with high blood pressure, heart or kidney disease or low potassium levels, or who takes diuretics, should clarify the glycyrrhizin content of a product with a physician or pharmacy. The BfR advises less than 100 mg of glycyrrhizin per day from all sources, licorice candy included.

Persistent heartburn, difficulty swallowing, weight loss or blood in the stool should be checked by a physician before self-treating. In the BK-Score, safety stands at 4 out of 10 points; this axis measures how well safety has been studied, not how safe the extract is. For stomach complaints there are separate pages on mastic and betaine HCl. This text is information and does not replace medical advice.

BK-Score Thin human evidence

Human evidence		4
Mechanism		3
Safety data		4
Hype gap		4
Track record of use		6

Evidence 4, because the older placebo-controlled studies in gastric and duodenal ulcers found no benefit (Feldman 1971 with 47, Bardhan 1978 with 96 patients, Engqvist 1973), while three newer double-blind studies with a single special extract show better results in dyspepsia (Raveendra 2012), reflux symptoms (Raj 2025, 200 participants) and in the Helicobacter test (Puram 2013); independent replications with other DGL products are lacking. Mechanism 3, because the advertised effect on the mucosa and the effect against Helicobacter come mainly from laboratory and animal experiments; the only thing clearly understood is what DGL no longer does, namely shift the mineral balance via glycyrrhizin. Safety 4, because the studies lasted only 4 to 8 weeks and the residual glycyrrhizin content of food supplements is not uniformly regulated; for glycyrrhizin itself there is a clear BfR limit of less than 100 mg per day. Hype 4, because DGL is widely marketed for heartburn, functional dyspepsia and stomach ulcers, but the ulcer studies were negative and the positive data depend on one extract. Use 6, because DGL products have been used for stomach complaints for decades, with clinical studies since the 1970s. Direction mixed: negative in ulcers, positive in the newer studies on dyspepsia and reflux.

The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless. “Track record of use 9” means used long and widely – that is not proof of efficacy.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about DGL licorice (deglycyrrhizinated)

What is the difference between DGL and regular licorice?

In DGL, the glycyrrhizin has largely been removed. In larger amounts, glycyrrhizin makes the body retain sodium, excrete potassium and raise blood pressure. Regular licorice root and licorice candy contain it, DGL only in residual amounts; the study extract GutGard at most 3 percent.

Does DGL help with heartburn?

In a double-blind study with 200 participants, heartburn and belching subsided faster under the special extract GutGard than under placebo, and quality of life was better after 28 days. That is one study with one extract. Whether other DGL products work the same way has not been tested.

Does DGL heal stomach ulcers?

The placebo-controlled studies from the 1970s did not find this. In 96 patients with gastric ulcer and in 47 patients with duodenal ulcer, no more ulcers healed under DGL than under placebo. Ulcers belong in medical treatment.

Can DGL raise blood pressure?

The blood-pressure-raising substance in licorice is glycyrrhizin, and it is largely removed in DGL. How much remains, however, is not uniformly regulated for food supplements. The BfR advises less than 100 mg of glycyrrhizin per day from all sources. With high blood pressure or heart medication, clarify the content beforehand.

Does DGL help against Helicobacter pylori?

In a study with 107 infected people, the stool antigen test was negative after 60 days in 56 percent under GutGard and in 4 percent under placebo. DGL was not compared with the usual eradication therapy. A confirmed infection is treated by a physician.

Same goal: better digestionBetaine HCl (betaine hydrochloride)
Same goal: better digestionMastic (mastic gum)
Same goal: better digestionProbiotics
Same goal: better digestionOx bile
Same goal: better digestionSodium butyrate
Same goal: better digestionActivated charcoal

Sources

Open in the database – with search, filters and comparison (German app)

Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-10-05.