A form of Licorice, known as DGL (deglycyrrhizinated Licorice) is used for digestive disorders such as GERD, peptic ulcers and canker sores. This special form of Licorice, DGL, was created to limit the adverse metabolic effects of Licorice. A substance called glycyrrhiza was removed from Licorice in order to eliminate the metabolic side effects.
Use of whole licorice has not been associated with significant adverse effects in the short term. However, two or more weeks of use may cause high blood pressure, fluid retention, and symptoms related to loss of potassium. 1 Such effects are especially dangerous for people who take the drug digoxin or medications that deplete the body of potassium (such as thiazide and loop diuretics ), or who have high blood pressure, heart disease, diabetes, or kidney disease.
Current evidence indicates that individuals who wish to take whole licorice on a long-term basis without any risk of these side effects should not consume more than 0.2 mg of glycyrrhizin per kilogram of body weight daily. 2 For a person who weighs 130 pounds, this works out to 12 mg of glycyrrhizin daily. Based on a typical 4% glycyrrhizin content, this is the equivalent of 0.3 grams of licorice root.
Whole licorice may have other side effects as well. For example, it appears to reduce testosterone levels in men. 3 For this reason, men with impotence , infertility , or decreased libido may wish to avoid this herb. Licorice may also increase both the positive and negative effects of corticosteroids such as prednisone and hydrocortisone cream. 4 5 In addition, some evidence suggests that licorice might affect the liver's ability to metabolize other medications as well, but the extent of this effect has not been fully determined. 6 Whole licorice possesses significant estrogenic activity, 7 and some evidence indicates that licorice increases risk of premature birth. 8 For these reasons, it shouldn't be taken by pregnant or nursing women, or women who have had breast cancer.
Maximum safe doses for young children, nursing women, or those with severe liver or kidney disease have not been established.
It is believed, but not proven, that most or all of the major side effects of licorice are due to glycyrrhizin. For this reason, DGL has been described as entirely safe. However, comprehensive safety studies on DGL have not been reported.
If you are taking:
Licorice can be taken in the following forms:
Dried root: 1 - 5 g as an infusion or decoction, three times daily
Licorice 1:5 tincture: 2 - 5 mL, three times daily
Standardized extract: 250 - 500 mg, three times daily, standardized to contain 20 % glycyrrhizinic acid
For peptic ulcer:
DGL extract: 0.4 - 1.6 g, three times daily,
DGL extract 4:1: chew 300 - 400 mg, three times daily 20 minutes before meals
Any licorice product should not be used for longer than 4 - 6 weeks.
Some studies have shown that DGL and antacids helped treat ulcers. However, since antacids were given with DGL, it's not possible to quantify how much of the benefit came from DGL alone. One animal study found that aspirin coated with licorice decreased the number of ulcers in rats by 50%. In one study, licorice root fluid extract was given to 100 patients with stomach ulcers for 6 weeks. The investigators reported that 90% of participants experienced improvement of symptoms; ulcers disappeared in 22 of the participants. Other studies fail to show any effects of DGL on peptic ulcers in humans.
The mechanism of action of the peptic ulcer-healing activity of DGL is not completely understood. In animal studies, DGL was found to boost the differentiation of glandular cells in the forestomach of a rat, and stimulate mucus secretion. The stimulation of mucus secretion in the stomach is believed to contribute to the healing properties of DGL. Deglycyrrhizinated licorice has some flavonoids that have antimicrobial properties including effects against the ulcer-causing bacterium Helicobacter pylori.
