Benefits
The H. pylori figure is not supported here
A figure of 56% versus 4% on placebo for clearing H. pylori has been quoted for deglycyrrhizinated licorice (DGL), but that study is not among the four references on this page, so the figure is uncited and cannot be checked here. Clearing an infection is also a medical outcome rather than a supplement benefit, and it is not something a supplement may claim. A confirmed H. pylori infection is a matter for your doctor.
Ulcer claims are not supported here
DGL has been described as being as effective as H2 blocker medicines for duodenal ulcer resolution. No reference on this page supports that comparison, and a supplement cannot be presented as an equivalent to prescription medicine for a diagnosed condition. Licorice does have a long traditional use for epigastric discomfort and indigestion, but that describes a tradition rather than a demonstrated effect. Ulcer symptoms need a doctor.
The reflux trial is not cited on this page
A trial of a standardized DGL extract in adults with reflux symptoms is sometimes cited for this ingredient, but it is not among the four references here, so nothing on this page documents it. Gastroesophageal reflux disease is a diagnosed condition and relieving it is not a supplement claim. Persistent heartburn should be looked at by a clinician.
Mucosal effects are mechanistic, not demonstrated
Licorice flavonoids have been described as having anti-inflammatory and antioxidant activity on the gastrointestinal lining. That is laboratory and mechanistic reasoning. No reference on this page measured any digestive outcome in people taking an oral licorice product, so none of it should be read as evidence that a supplement heals tissue or repairs damage caused by medication.
Glabridin is a topical cosmetic ingredient
Glabridin inhibits tyrosinase in laboratory assays, which is why it appears in topical skin-lightening cosmetics applied to the surface of the skin. Nothing on this page shows that swallowing a licorice extract changes skin pigmentation, and this site covers oral supplements only.
Licochalcone A is also a topical ingredient
Licochalcone A is used in leave-on skin care for redness and blemish-prone skin. As with glabridin, that evidence is topical and does not transfer to a capsule taken by mouth. No reference on this page tested either flavonoid taken orally.
Reduced side effect profile via deglycyrrhizination
Deglycyrrhizinated licorice (DGL) has had the glycyrrhizin taken out, so it does not carry the mineralocorticoid effect of native licorice, which produces sodium retention, potassium loss and raised blood pressure. That distinction matters, because the cited work documents real harm from the native compound: systolic blood pressure rose 3.1 to 14.4 mmHg across the doses tested, adverse effects can begin in sensitive people at a regular intake of about 100 mg of glycyrrhizic acid a day, and most people taking 400 mg a day experience them. DGL avoids that mechanism. It does not follow that DGL has a proven benefit, because no oral efficacy study is cited on this page.
Neurological work is in animals only
Licorice flavonoids have been reported to modulate GABA signaling, and liquiritigenin reduced glutamate toxicity in mouse hippocampal neurons. That work is in mice and in isolated cells, and none of it is cited on this page. Animal seizure models describe a disease and cannot support a claim for people, and nothing here shows an effect on human brain function. Treat it as early laboratory background only.
Mechanism of action
Mucosal protection via flavonoid anti-inflammatory
Licorice flavonoids have been reported in laboratory work to reduce inflammatory signaling, including NF-κB and COX-2 activity. This is a proposed mechanism for the gastrointestinal lining. It is not tied to any measured outcome in the references on this page.
Antimicrobial activity in the laboratory
Licorice-derived flavonoids have shown activity against Helicobacter pylori in laboratory testing. The eradication percentages quoted elsewhere on this page come from a study that is not cited here, so they cannot be verified, and activity in a dish is not evidence that a supplement clears an infection in a person.
Tyrosinase inhibition (topical cosmetic use)
Glabridin inhibits tyrosinase, the rate-limiting enzyme in melanin synthesis, in laboratory assays. That is the basis for its use in cosmetics applied to the skin. It is not a mechanism for an oral supplement, and no reference here compares it with any medicine.
11β-HSD2 inhibition (native glycyrrhizin)
Native glycyrrhizin (not present in DGL) inhibits 11β-hydroxysteroid dehydrogenase type 2 — the enzyme that inactivates cortisol. Cortisol is then free to act on the mineralocorticoid receptor, which produces sodium and water retention, potassium loss, edema and raised blood pressure. A controlled human study found a linear dose response, with systolic blood pressure rising 3.1 to 14.4 mmHg at intakes of 75 to 540 mg of glycyrrhetinic acid per day over two to four weeks. Deglycyrrhizination removes the compound responsible, and with it this mechanism.
GABAergic modulation and neuroprotection
Licorice flavonoid extracts have been reported to modulate GABA signaling, and liquiritigenin reduced glutamate toxicity in mouse hippocampal neurons in cell work. All of this is animal and cell data, none of it is cited on this page, and it says nothing about what an oral licorice supplement does in people.
Clinical trials
This study is not among the four references on this page, and no author, journal, year or PubMed identifier is given for it, so its design and size cannot be checked. It is listed here as uncited.
Not verifiable. The population, the number of participants and the length of the intervention are all unsourced.
The 56% against 4% eradication figure cannot be traced to any reference on this page, so it is reported here only as an unverified claim rather than a supported result. Clearing a bacterial infection is in any case a medical outcome that a supplement may not claim.
No reference on this page corresponds to this trial. The phase III label, the design and the 28-day duration are unsourced and cannot be verified.
Given as 200 adults with reflux symptoms, but the figure is unsourced and cannot be confirmed.
Reported as a benefit for reflux symptoms with no citation behind it. Reflux disease is a diagnosed condition and a supplement may not be offered as relief for it. Nothing on this page documents this result.
These licorice flavonoid oil studies are not among the references on this page. They also concern a different material from the DGL and glycyrrhizin products described above, so they would not support claims for those even if they were cited.
Given as about 50 people in the knee study and 11 to 17 in the small metabolic studies, all unsourced. Studies of that size are exploratory.
The reported change in trunk muscle mass was a gain of 0.17 kg with the extract against a loss of 0.57 kg on placebo, with standard deviations of about 1 kg, which is wider than the difference between the groups. The AMPK and fat oxidation statements are mechanistic. None of it is cited on this page, and knee osteoarthritis is a diagnosed joint disease that a supplement may not claim to treat.