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DGL for Health & Longevity

Evidence Review created on 09/20/2026 using AI4L / Opus 5

Also known as: Deglycyrrhizinated Licorice, Deglycyrrhizinated Liquorice, Deglycyrrhizinised Liquorice, DGL Licorice, Caved-S, Rhizinate, GutGard

Motivation

Deglycyrrhizinated licorice (DGL) is licorice root extract from which glycyrrhizin — the intensely sweet compound that gives licorice its flavour and its capacity to raise blood pressure — has largely been stripped out. What remains is an extract of the root’s other plant compounds, sold as chewable tablets, capsules and powders, used mainly for stomach and oesophageal complaints. The stated purpose of the processing is to keep whatever soothing action licorice has on the gut lining while discarding the compound responsible for its best-documented harm.

Licorice root has been in medical use for thousands of years, and the modern separation of the plant into a “useful” and a “dangerous” fraction dates to the middle of the twentieth century, when licorice paste was observed to help stomach ulcers and was then found to cause fluid retention and potassium loss. Deglycyrrhizinated preparations were an attempt to resolve that tension.

This review examines what controlled human evidence exists for deglycyrrhizinated licorice, how completely the two fractions are separated in commercial products, and how the claims made for the preparation compare with the data behind them.

Benefits - Risks - Protocol - Conclusion

This section lists high-level overviews of deglycyrrhizinated licorice and of licorice root pharmacology that discuss the intervention in substantial depth.

Searches of foundmyfitness.com returned nothing on licorice, and peterattiamd.com returned only a passing mention of licorice confectionery inside an episode on sugar substitutes. Hubermanlab.com carries a cortisol episode with a segment on glycyrrhizin raising cortisol and blood pressure, and lifespan.io carries an article on a Chinese-licorice flavonoid in stem-cell culture, but neither addresses the deglycyrrhizinated fraction or the mucosal mechanism at issue here, so neither qualifies as a high-level overview of this topic. Five qualifying items were found, so the list is complete without padding.

Grokipedia

  • Deglycyrrhizinated licorice

    The site’s dedicated article on the intervention, covering the deglycyrrhizination process, the glycyrrhizin content thresholds used commercially, and the historical ulcer trials.

Examine

  • Licorice

    Examine’s primary licorice monograph, which grades the human evidence by outcome and states directly that deglycyrrhizinated products should pose less risk than whole licorice.

ConsumerLab

Systematic Reviews

PubMed holds no systematic review or meta-analysis of deglycyrrhizinated licorice itself, so the pooled evidence below covers licorice root and its separated fractions, spanning both the claimed digestive benefits and the principal cardiovascular and electrolyte risk.

Mechanism of Action

Licorice acts on the stomach and oesophagus mainly by strengthening mucosal defence rather than by blocking acid. Removing glycyrrhizin leaves a preparation dominated by flavonoids such as glabridin, glabrol and liquiritigenin.

In animal work, deglycyrrhizinated licorice increases mucus-secreting cells per gastric gland and accelerates their turnover, thickening the protective mucus layer (van Marle et al., 1981). It is also proposed to raise local prostaglandin availability — prostaglandins are fat-derived signalling molecules that drive mucus and bicarbonate secretion and maintain mucosal blood flow — although a rat study found little or no effect on gastric prostanoid synthesis, so this limb is disputed (Bennett et al., 1985). Separately, licorice polysaccharides block adhesion of Helicobacter pylori to human gastric tissue without killing the organism (Wittschier et al., 2009), and flavonoid-rich extracts inhibit both cyclo-oxygenase (COX, the enzyme that makes prostaglandins) and lipoxygenase (LOX, which makes leukotrienes) in laboratory assays (Chandrasekaran et al., 2011) — work by the extract’s manufacturer, Natural Remedies, which has a direct financial interest.

Pharmacologically this is a plant extract, not a single compound. Glabridin, the usual marker flavonoid, is poorly absorbed, is conjugated by UGT enzymes (which attach sugar groups to speed excretion) and sulfotransferases (which attach sulfate groups to the same end) in gut wall and liver, and is cleared within hours, so systemic exposure is low and action is largely local. Residual glycyrrhizin behaves differently: gut bacteria convert it to glycyrrhetinic acid, which has a terminal half-life of roughly 10–30 hours and accumulates with daily dosing.

Historical Context & Evolution

Licorice root has been used for cough, thirst and stomach complaints across Egyptian, Greek and Chinese medical traditions for millennia. Its modern medical career began in 1946, when a Dutch physician noticed that patients taking a licorice paste for stomach pain showed ulcer improvement on follow-up. Systematic study followed, and by the 1950s it was clear that the same preparations caused facial swelling, sodium retention and potassium loss.

That finding split the field in two directions. One line isolated glycyrrhetinic acid and developed carbenoxolone, a prescription ulcer drug widely used in Britain into the 1980s, accepting the mineralocorticoid effects as a manageable cost. The other line removed glycyrrhizin entirely, producing deglycyrrhizinated preparations such as Caved-S in the 1960s on the hypothesis that the healing action and the toxicity were separable.

The controlled trials that followed did not settle the matter. A gastric-ulcer trial reported benefit (Turpie et al., 1969), while a duodenal-ulcer trial (Feldman & Gilat, 1971) and a larger crossover gastric-ulcer trial (Engqvist et al., 1973) found none. What changed after 1976 was not a verdict on licorice but the arrival of histamine H2-receptor blockers (drugs such as cimetidine that shut down acid production) and later proton-pump inhibitors (drugs that shut down stomach acid production more completely), which healed ulcers reliably and made the question commercially uninteresting. Deglycyrrhizinated licorice survived in naturopathic practice and returned to trials after 2010 in standardised flavonoid-rich form.

Expected Benefits

High 🟩 🟩 🟩

Relief of Reflux and Dyspepsia Symptoms

Flavonoid-rich deglycyrrhizinated extracts reduce heartburn, regurgitation, epigastric pain (pain just below the breastbone) and upper abdominal fullness. The proposed mechanism is mucosal defence, not acid suppression. Two randomised, double-blind, placebo-controlled trials support this: 50 patients with functional dyspepsia (indigestion with no ulcer found) over 30 days, and 200 patients with reflux symptoms over 28 days, both using validated symptom scales. Both tested the same standardised extract, and the dyspepsia trial was co-authored by staff of its manufacturer, Natural Remedies — a direct financial interest in the result.

Magnitude: 15 of 25 patients (60%) taking 75 mg twice daily were symptom-free or markedly improved at 30 days versus none of 25 on placebo in functional dyspepsia (Raveendra et al., 2012); in reflux, heartburn and regurgitation resolved earlier from day 7 onward, with p = 0.005 for heartburn at day 28 (p, the probability that a difference this large arose by chance) (Raj et al., 2025).

Medium 🟩 🟩

Reduction of Helicobacter pylori Bacterial Load

Helicobacter pylori is the stomach bacterium behind most ulcers and a recognised gastric cancer risk. A single randomised, double-blind, placebo-controlled trial in 107 infected participants found that a deglycyrrhizinated extract lowered measured bacterial load over 60 days. Laboratory work on the same extract points to interference with the bacterium’s protein and DNA machinery rather than to blocked adhesion (Asha et al., 2013); the trial measured load, not cure, so this is suppression, not eradication. The trial was conducted with manufacturer-affiliated authors, and no independent replication exists.

Magnitude: After 60 days at 150 mg daily, 28 of 50 participants (56%) tested stool-antigen negative versus 2 of 50 (4%) on placebo, and 24 of 50 (48%) turned negative on the carbon-13 urea breath test (Puram et al., 2013).

Low 🟩

Healing of Peptic Ulcers ⚠️ Conflicted

Four controlled trials of the classic preparation disagree. One reported benefit in gastric ulcer (Turpie et al., 1969); three others found none (Feldman & Gilat, 1971; Engqvist et al., 1973; Bardhan et al., 1978), the two larger finding no difference in healing. Net reading: ulcer healing is not established.

Magnitude: In the crossover trial neither change in ulcer area nor complete-healing rate differed from placebo across two four-week periods at 760 mg three times daily, and the 96-patient trial found no difference by gastroscopy or radiology; the literature provides no pooled outcome figure.

Prevention of Gastric Ulcer Recurrence

After endoscopic healing, the classic preparation held recurrence rates close to those of an acid-blocking drug over one and two years (Morgan et al., 1982; Morgan et al., 1985). Neither trial carried a placebo arm, so equivalence cannot separate a real effect from natural healing.

Magnitude: Recurrence reached 12% at one year and 29% at two years on the deglycyrrhizinated preparation versus 10% and 25% on cimetidine across 82 patients (Morgan et al., 1985).

Protection of the Stomach Lining Against Aspirin

Co-administration reduced aspirin-induced gastric injury in rats and reduced faecal blood loss in humans given high-dose aspirin (Rees et al., 1979). The human observation is small, old and uncontrolled, and has never been repeated against modern anti-inflammatory drugs, which limits how far it can be carried.

Magnitude: Faecal blood loss induced by 975 mg aspirin three times daily was lower when 350 mg was given with each aspirin dose; the report states direction only and the literature gives no outcome figure.

Faster Healing of Mouth Ulcers

An uncontrolled series of 20 patients using a deglycyrrhizinated mouthwash reported rapid relief of aphthous ulcers (small recurrent mouth sores) (Das et al., 1989). Controlled trials in this indication used whole licorice patches and gels rather than the deglycyrrhizinated fraction, so the specific evidence remains uncontrolled.

Magnitude: 15 of 20 patients reported 50–75% improvement within one day and complete healing by the third day, with no control group for comparison.

Speculative 🟨

Suppression of Cavity-Forming Oral Bacteria

Deglycyrrhizinated root extract inhibited Streptococcus mutans growth and biofilm formation in culture (Ahn et al., 2012). The basis is laboratory growth-inhibition assays only; no human caries outcome has been measured.

Reinforcement of the Intestinal Barrier

A flavonoid-rich deglycyrrhizinated extract cut leakage across cultured intestinal cells and raised tight-junction proteins in rat colitis (Murugan et al., 2022). The basis is manufacturer-run laboratory and animal data; no human outcome exists.

Benefit-Modifying Factors

  • Flavonoid standardisation of the product: Trials showing benefit used extracts standardised to defined glabridin and total-flavonoid content. Unstandardised chewables may carry a fraction of that flavonoid load, so results from the trial material do not automatically transfer.

  • Baseline symptom severity: Benefit in the reflux and dyspepsia trials was measured as change on symptom scales in people with active, troublesome symptoms. Those with mild or intermittent complaints have proportionally less room to improve.

  • Helicobacter pylori status: Where infection is present, part of any symptom benefit may come from the reduced bacterial load. Where it is absent, only the mucosal-defence pathway is available, and the expected effect is smaller.

  • Concurrent anti-inflammatory drug use: The mucosal-protection signal was generated against aspirin exposure. People taking regular anti-inflammatory drugs have a defence deficit to correct, and are the group in which protection would be most visible.

  • Co-use of acid-suppressing medication: Proton-pump inhibitors already remove most acid-driven symptoms. Added benefit from a mucosal agent is harder to detect against that background.

  • Genetic variation in flavonoid metabolism: Common variants in UGT1A1 (an enzyme that attaches sugar groups to compounds for excretion) alter clearance of dietary flavonoids and plausibly shift local and systemic exposure, though no deglycyrrhizinated licorice study has tested this directly.

  • Sex-based differences: No trial has reported outcomes separately by sex, and the reflux and dyspepsia trials enrolled both men and women in near-equal numbers. Any sex difference in benefit is currently unmeasured rather than absent.

  • Pre-existing gastrointestinal conditions: Ulcer disease, erosive oesophagitis (visible damage to the oesophageal lining) and functional dyspepsia respond differently. The positive trials enrolled functional and non-erosive presentations; evidence in ulcer disease is conflicted, so condition selects the expected benefit.

  • Age: Trial populations were mostly middle-aged adults, with the reflux trial recruiting up to conventional adult ages. In older adults, thinner mucus layers and more frequent anti-inflammatory drug use argue for more to gain, but no trial has confirmed this.

Potential Risks & Side Effects

High 🟥 🟥 🟥

Raised Blood Pressure, Sodium Retention and Potassium Loss ⚠️ Conflicted

Glycyrrhizin blocks 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2, the enzyme that stops cortisol acting on salt-handling receptors in the kidney), producing pseudohyperaldosteronism (a salt-retaining state raising blood pressure and lowering potassium). Two meta-analyses size this effect in humans. Whether deglycyrrhizination removes it is disputed: pooled flavonoid-dominant products shifted blood pressure not at all, yet a deglycyrrhizinated preparation alone raised sodium and lowered potassium in healthy subjects, and product testing keeps finding glycyrrhizic acid in deglycyrrhizinated-labelled products. Net reading: the harm belongs to glycyrrhizin, so it tracks what a product actually retains.

Magnitude: Pooled across 18 studies, systolic pressure rose 5.45 mmHg (95% confidence interval, the range within which the true value probably lies, 3.51–7.39), diastolic 3.19 mmHg (0.10–6.29), and plasma potassium fell 0.33 mmol/L (Penninkilampi et al., 2017); a second meta-analysis found systolic +3.48 mmHg (2.74–4.21) for glycyrrhizic-acid-dominant products and no change for flavonoid-dominant ones (Wu et al., 2024). A deglycyrrhizinated preparation alone raised serum sodium and lowered serum potassium in healthy volunteers (Baas et al., 1976).

Medium 🟥 🟥

Harm to Pregnancy and Child Development

Glycyrrhizin blocks the placental form of the same enzyme it blocks in the kidney, letting maternal cortisol reach the fetus. A Finnish birth cohort followed children to age 12 and found that heavy maternal licorice intake during pregnancy tracked with lower measured intelligence, more attention problems and earlier puberty in girls. The evidence is observational and consistent rather than experimental, and it is carried by glycyrrhizin, so a deglycyrrhizinated product transmits it only in proportion to what it still contains.

Magnitude: Children of mothers consuming 500 mg or more of glycyrrhizin weekly scored 7 points lower on intelligence testing (95% confidence interval 3.1–11.2) and had 3.3-fold higher odds of attention-deficit problems (1.4–7.7) than children of mothers consuming 249 mg or less weekly, across 378 children (Räikkönen et al., 2017).

Low 🟥

Reduced Serum Testosterone ⚠️ Conflicted

Licorice lowered serum testosterone in small uncontrolled studies in men and women, attributed to glycyrrhizin blocking androgen-synthesis enzymes (Armanini et al., 2003; Armanini et al., 2004). Two salivary replication attempts failed (Josephs et al., 2001). No deglycyrrhizinated preparation has been tested. Net reading: unresolved, and carried only by residual glycyrrhizin.

Magnitude: Mean serum testosterone fell 26% after one week of daily licorice in men (p < 0.01) (Armanini et al., 2003), and from 27.8 to 17.5 ng/dL over two cycles in nine women taking 3.5 g of a licorice preparation daily (Armanini et al., 2004).

Cardiac Rhythm Disturbance in Long-Term Users

Severe potassium depletion can provoke extra heartbeats and, at the extreme, life-threatening arrhythmia. A published case describes this in a patient who had taken deglycyrrhizinated licorice for years, presenting with high blood pressure, low potassium, a sinus pause (a missed heartbeat) and fainting (Patel et al., 2021).

Magnitude: Not quantified in available studies. No controlled trial has measured cardiac rhythm outcomes on deglycyrrhizinated licorice; the evidence consists of individual case reports, which cannot yield an incidence.

Nausea and Abdominal Discomfort

Nausea and digestive upset are the side effects most often logged for licorice preparations (Kwon et al., 2020). Chewable tablets add sugar alcohols such as sorbitol and mannitol, which themselves cause bloating and loose stools. Reports are uncontrolled and no trial has separated extract from excipient.

Magnitude: Not quantified in available studies. The controlled trials of deglycyrrhizinated extracts reported tolerability as comparable to placebo without publishing per-symptom rates, so no incidence figure exists.

Speculative 🟨

Oestrogen-Receptor Activity of Licorice Flavonoids

Glabridin and related isoflavans bind oestrogen receptors in laboratory assays, raising theoretical concern in hormone-sensitive conditions. The basis is in-vitro binding work only; no human hormonal or clinical outcome has been measured on deglycyrrhizinated licorice.

Forfeiting Glycyrrhizin’s Own Systemic Effects

Removing glycyrrhizin also removes the compound behind licorice’s antiviral, liver and inflammation-signalling effects, including a rodent report of preserved levels of a longevity-linked protein (Ohnishi et al., 2026). The basis is animal work only.

Risk-Modifying Factors

  • Genetic variation in 11β-HSD2: Variants in the HSD11B2 gene, which encodes the enzyme glycyrrhizin blocks, produce wide differences in sensitivity. Carriers of reduced-function variants develop pressure and potassium changes at intakes others tolerate.

  • Baseline potassium and blood pressure: Someone starting at 3.6 mmol/L potassium or 138/88 mmHg has far less margin than someone at 4.4 mmol/L and 112/70 mmHg before residual glycyrrhizin produces a clinically meaningful shift.

  • Baseline plasma renin and aldosterone: Already-suppressed renin (the kidney enzyme that triggers salt-retaining hormones) and aldosterone indicate an active mineralocorticoid-like load. Adding a glycyrrhizin source on top compounds it, and the suppression itself is the earliest laboratory sign.

  • Sex-based differences: Reported case series of licorice-induced pseudohyperaldosteronism skew towards women, and women appear to show electrolyte effects at lower intakes (Nazari et al., 2017). The evidence is observational and confounded by consumption patterns rather than established physiology.

  • Pre-existing cardiovascular, kidney and liver disease: Hypertension, heart failure, chronic kidney disease and cirrhosis all impair potassium and sodium handling. Each converts a mild electrolyte shift into a clinically consequential one.

  • Age: Older adults have reduced kidney potassium-conserving capacity, higher baseline blood pressure and greater use of diuretics, so the same residual glycyrrhizin exposure produces larger and less well tolerated shifts.

Key Interactions & Contraindications

  • Potassium-wasting diuretics (furosemide, hydrochlorothiazide, chlortalidone): Caution, potentially severe. Additive potassium loss can produce muscle weakness and arrhythmia. Mitigation: potassium measurement before starting and at four weeks, and a product with stated glycyrrhizin content.

  • Digoxin: Caution bordering on avoidance. Low potassium sharply increases digoxin toxicity, causing nausea, visual disturbance and arrhythmia. Mitigation: complete avoidance of glycyrrhizin-containing products, or potassium and digoxin level monitoring where they are used.

  • Corticosteroids (prednisolone, hydrocortisone, topical steroids): Caution. Glycyrrhizin slows cortisol breakdown and amplifies steroid effect, raising the risk of fluid retention and raised blood sugar. Mitigation: separation of use, or avoidance during steroid courses.

  • Antihypertensive medication of any class: Monitor. Residual glycyrrhizin can partially offset blood-pressure control. Mitigation: home blood-pressure logging for the first month after starting, with the product stopped if readings drift upward.

  • Over-the-counter anti-inflammatory drugs (ibuprofen, naproxen, aspirin): Monitor, favourable direction. These agents damage the gastric lining; mucosal support is the plausible benefit rather than a hazard. No dose separation is required.

  • Over-the-counter antacids and alginates: Monitor. Both act locally in the stomach and can blunt the chewable tablet’s contact with the mucosa. Mitigation: separate administration by at least one hour.

  • Potassium-lowering supplements and foods (high-dose caffeine, whole licorice confectionery, licorice teas): Caution. Stacked glycyrrhizin sources are the common route to symptomatic potassium loss. Mitigation: a running total of daily glycyrrhizin across all sources.

  • Blood-pressure-lowering supplements (potassium, magnesium, beetroot nitrate, hibiscus): Monitor, opposing direction. These can mask a rising glycyrrhizin load by holding blood pressure down while potassium still falls. Mitigation: potassium tracking rather than pressure alone.

  • Drugs cleared by CYP3A4 (the main liver enzyme for drug breakdown; statins, calcium-channel blockers, ciclosporin): Monitor. Licorice constituents alter this enzyme unpredictably, so blood levels may rise or fall — statin muscle injury or lost ciclosporin cover. Mitigation: drug level checks where assays exist.

Populations who should avoid DGL:

  • Pregnancy at any stage, given the association of licorice intake with preterm delivery and impaired child cognitive outcomes
  • Breastfeeding, where glycyrrhizin is detectable in milk and safety data are absent
  • Uncontrolled hypertension (sustained readings above 140/90 mmHg)
  • Heart failure of New York Heart Association Class III or IV
  • Documented hypokalaemia (serum potassium below 3.5 mmol/L) from any cause
  • Chronic kidney disease at stage 3b or worse (estimated glomerular filtration rate, a measure of kidney filtering capacity, below 45 mL/min/1.73 m²)
  • Primary or secondary hyperaldosteronism, including Conn’s syndrome (conditions in which the adrenal glands already drive sodium retention and potassium loss)
  • Cirrhosis with ascites (fluid accumulation in the abdomen)

Risk Mitigation Strategies

  • Product selection on stated glycyrrhizin content: The relevant selection criterion is a declared glycyrrhizin content below 0.5% or below 1%, since independent testing has found labelled deglycyrrhizinated products still carrying meaningful glycyrrhizic acid. This directly limits pseudohyperaldosteronism risk.

  • Total glycyrrhizin counted across all sources: Combined intake from supplements, teas and confectionery stays under roughly 100 mg daily, the threshold above which blood-pressure and potassium effects begin appearing. This prevents stacked exposure from unrecognised sources.

  • Potassium measured before starting and at four weeks: A baseline and a four-week serum potassium catch the earliest sign of mineralocorticoid load before weakness or arrhythmia develops, and give a personal reference point rather than a population range.

  • Home blood-pressure log for the first month: Morning and evening readings for four weeks detect the 3–5 mmHg drift that residual glycyrrhizin produces. A sustained rise of 5 mmHg or more is the signal to stop.

  • Time-limited courses rather than continuous intake: Pseudohyperaldosteronism follows cumulative exposure, typically after four weeks or more of daily use. Courses of four to eight weeks with breaks limit the accumulation of glycyrrhetinic acid.

  • Avoidance through pregnancy and breastfeeding: Any licorice-derived product is set aside from conception until weaning, since residual glycyrrhizin crosses the placenta and reaches milk. This removes the cognitive, attention and pubertal-timing harm documented in children of high-intake mothers.

  • Excipient list on chewables: Sorbitol, mannitol and fructose in chewable tablets cause bloating and loose stools at multi-tablet doses. Choosing lower-sugar-alcohol formats prevents digestive upset being misattributed to the extract.

Therapeutic Protocol

  • Classic chewable dose: The historical preparation was dosed at 380–800 mg chewed three times daily. The crossover ulcer trial used 760 mg three times daily for four weeks.

  • Standardised extract dose: The modern flavonoid-rich extract was trialled at 75 mg twice daily for functional dyspepsia over 30 days, and 150 mg once daily for 60 days against Helicobacter pylori.

  • Competing approach — mucosal support: Naturopathic and integrative practice, represented by Chris Kresser’s protocol, positions this as mucosal restoration paired with dietary change rather than a substitute for acid suppression.

  • Competing approach — conventional suppression: Gastroenterology practice treats reflux and ulcer with proton-pump inhibitors and eradication antibiotics. Neither approach is presented here as the default; they target different parts of the problem.

  • Best time of day: Chewable formats are taken 15–20 minutes before meals so the mucus-stimulating action precedes the acid and food load. Capsules of standardised extract were trialled without meal timing.

  • Half-life and dosing frequency: Flavonoids clear within hours, which is why every trial used two or three daily doses rather than one. Split dosing is the tested pattern; single daily dosing was used only in the Helicobacter trial.

  • Chewing matters for chewables: The classic format is chewed rather than swallowed, mixing the extract with saliva so it coats the oesophagus and stomach lining. Swallowing the tablet whole defeats the intended mechanism.

  • Genetic polymorphisms and dose: HSD11B2 variants alter sensitivity to residual glycyrrhizin, so the safe upper dose is individual. No pharmacogenetic testing is established for this purpose; potassium measurement serves as the practical proxy.

  • Sex-based differences in dosing: No trial has dosed by sex. Given the female skew in reported licorice-induced pseudohyperaldosteronism, the lower end of the dose range is the more conservative starting point for women.

  • Age-related adjustment: Older adults, particularly those on diuretics or with reduced kidney function, warrant the lower dose range and shorter courses, since the same exposure produces larger electrolyte shifts.

  • Baseline biomarkers before dosing: Serum potassium, sodium and blood pressure define the available margin. Starting potassium below 4.0 mmol/L argues for the lowest dose or a different agent entirely.

  • Pre-existing conditions and dose choice: Hypertension, heart failure, kidney disease and diuretic use all shift the dose downward or rule the intervention out. Functional dyspepsia without these conditions supports the full trialled dose.

Discontinuation & Cycling

  • Intended duration: Every controlled trial ran 28 to 60 days. This is a short-course intervention for an active symptom problem, not a compound with evidence supporting lifelong daily use.

  • Withdrawal effects: None have been described. Symptoms may return when the mucosal support is removed, but no rebound acid hypersecretion or dependence phenomenon has been reported in any trial.

  • Tapering: No taper is required. Trials stopped the product abruptly at the end of the dosing period without adverse consequence, and the flavonoids clear within hours.

  • Cycling for efficacy: No evidence suggests tolerance develops, so cycling is not needed to maintain effect. Breaks between courses are justified on safety grounds instead, limiting cumulative glycyrrhetinic acid from residual glycyrrhizin.

  • Stopping for a safety signal: A sustained home blood-pressure rise of 5 mmHg or more, or a potassium fall below 3.8 mmol/L, is a reason to stop immediately rather than reduce the dose.

Sourcing and Quality

  • Verified glycyrrhizin content is the primary quality marker: Independent testing has found products labelled as deglycyrrhizinated still containing meaningful glycyrrhizic acid. A stated, tested figure below 0.5% is the single most useful label claim.

  • Flavonoid standardisation: The extracts used in the positive trials were standardised to defined glabridin and total-flavonoid content. Products declaring only “licorice root extract, deglycyrrhizinated” give no assurance of matching the trial material.

  • Third-party testing: A certification mark from an independent programme such as USP Verified, NSF Certified for Sport or ConsumerLab approval is the available assurance of content. Botanical extracts are among the categories most prone to species substitution and content shortfalls.

  • Species identity: Products may be made from Glycyrrhiza glabra, Glycyrrhiza uralensis or Glycyrrhiza inflata, which differ in flavonoid profile and drug-interaction potential. The trialled material was Glycyrrhiza glabra.

  • Format: Chewable tablets deliver the classic saliva-mixed exposure but carry sugar alcohols and sweeteners; capsules of standardised extract avoid those excipients but bypass oesophageal contact. Format choice therefore tracks which mechanism is being relied on.

  • Suppliers: The standardised extract used in the modern trials is manufactured by Natural Remedies and appears in finished products under licence. Chewable formats from Enzymatic Therapy, Natural Factors and Integrative Therapeutics are long-established.

Practical Considerations

  • Time to effect: Symptom trials measured change at 7 to 15 days, with further improvement by day 30. Bacterial-load reduction took 60 days. Nothing here acts within hours.

  • Pitfall — swallowing chewables whole: The classic format is designed to be chewed and mixed with saliva. Swallowing it intact removes the oesophageal and gastric contact that the mechanism depends on.

  • Pitfall — assuming deglycyrrhizinated means glycyrrhizin-free: Product testing repeatedly contradicts this assumption, and it is the direct cause of the blood-pressure and potassium cases reported in long-term users.

  • Pitfall — treating persistent symptoms indefinitely: Reflux or epigastric pain lasting beyond a few weeks, or with weight loss, swallowing difficulty or bleeding, needs investigation. Extended self-management delays diagnosis of ulcer and malignancy.

  • Pitfall — substituting for eradication therapy: The Helicobacter trial reduced bacterial load in about half of participants; it did not achieve eradication. Treating a confirmed infection with this alone leaves the cancer risk intact.

  • Regulatory status: Sold as a dietary supplement in the United States and a food supplement in the European Union, with no approved medicinal indication in either. Manufacturing is not held to pharmaceutical standards.

  • Cost and accessibility: Inexpensive and widely available without prescription, typically a few cents per chewable tablet. Neither cost nor access is a meaningful barrier, which is why product quality carries the whole burden.

Interaction with Foundational Habits

  • Sleep: Indirect and modest. Night-time reflux fragments sleep, so symptom relief can improve sleep continuity; the pathway runs through the symptom, not through sleep physiology. Residual glycyrrhizin raises cortisol exposure, which in principle cuts the other way. Taking the evening dose with the last meal rather than at bedtime is the practical point.

  • Nutrition: Direct and bidirectional. Chewables are taken before meals, so the intervention is anchored to eating patterns. Adequate dietary potassium from vegetables and fruit offsets the potassium-lowering direction of residual glycyrrhizin. Confectionery licorice and licorice-containing herbal teas are themselves glycyrrhizin sources rather than unrelated foods.

  • Exercise: Indirect, with one specific caution. No effect on strength, endurance or muscle adaptation has been reported, and licorice is not a prohibited substance under the 2026 World Anti-Doping Agency list. Endurance athletes losing potassium and sodium through sweat have less electrolyte margin, making baseline potassium measurement more important rather than less.

  • Stress management: Indirect and potentially blunting. Glycyrrhizin prolongs cortisol’s action at kidney receptors, so residual amounts add to the physiological load that stress-management practices are meant to reduce. Deglycyrrhizinated products should carry little of this, which is a further argument for buying on verified glycyrrhizin content.

Monitoring Protocol & Defining Success

Baseline testing establishes how much electrolyte and blood-pressure margin exists before any glycyrrhizin-containing product is introduced, and gives a personal reference point that population ranges cannot. A sensible baseline covers serum potassium, sodium and magnesium, an estimated glomerular filtration rate, and a week of home blood-pressure readings taken morning and evening. Where a Helicobacter pylori benefit is the goal, a stool antigen or carbon-13 urea breath test establishes infection status first.

Ongoing monitoring is light for a short course and tightens with duration. Home blood pressure is logged daily for the first four weeks, then weekly. Serum potassium and sodium are repeated at four weeks, and again at twelve weeks for anyone continuing beyond a single course or taking diuretics. Kidney function is checked every six to twelve months in continuous users.

Biomarker Optimal Functional Range Why Measure It? Context/Notes
Serum potassium 4.0–4.5 mmol/L Earliest signal of glycyrrhizin load Conventional reference range is a much wider 3.5–5.2 mmol/L, so a fall from 4.4 to 3.7 reads as “normal” while representing a real shift. Fist clenching during the draw falsely raises the result
Serum sodium 135–142 mmol/L Detects the sodium retention side of the same mechanism Conventional range extends to 145 mmol/L. Best paired with potassium on the same draw; rises and potassium falls travel together
Home blood pressure Below 120/80 mmHg averaged over 7 days The clinical endpoint the risk is defined by Single clinic readings are too noisy to detect a 3–5 mmHg drift. Readings are taken seated, after 5 minutes’ rest, morning and evening
Serum magnesium 2.0–2.4 mg/dL Low magnesium makes potassium loss harder to correct Conventional range starts near 1.6 mg/dL. Red-blood-cell magnesium (5.0–6.5 mg/dL) reflects stores better than serum, which holds steady until depletion is advanced
Plasma renin activity 1.0–3.0 ng/mL/hour, upright Suppression confirms a mineralocorticoid-like load Conventional range is 0.5–4.0 ng/mL/hour. Strongly posture- and time-dependent: draw mid-morning after 30 minutes upright, and repeat under the same conditions
Serum aldosterone 5–15 ng/dL, upright Falls alongside renin under glycyrrhizin exposure Interpreted only alongside renin as a ratio; either value alone is uninformative. Same posture and timing rules as renin
Estimated glomerular filtration rate 90 mL/min/1.73 m² or above Defines how well potassium can be conserved Below 45 mL/min/1.73 m² the intervention is contraindicated. Heavy exercise and high creatine intake depress the result for about 48 hours
Helicobacter pylori stool antigen or urea breath test Negative The endpoint if bacterial load is the goal No optimal range applies; the result is binary. Requires 2 weeks off proton-pump inhibitors and 4 weeks off antibiotics or the result is falsely negative

Qualitative markers to track alongside the laboratory values:

  • Frequency and intensity of heartburn and regurgitation, recorded daily rather than recalled weekly
  • Epigastric pain and upper abdominal fullness after the largest meal of the day
  • Sleep continuity, specifically waking episodes attributable to night-time reflux
  • Unusual muscle weakness, cramping or palpitations, which point towards potassium loss
  • Facial or ankle swelling and unexplained weight gain over days, which point towards sodium retention
  • Whether symptom relief persists in the week after a course ends, which distinguishes mucosal recovery from symptomatic cover

Emerging Research

  • Licorice alongside standard eradication therapy: NCT07729293 randomises 140 adults, double-blind and placebo-controlled, to a Lactobacillus rhamnosus plus dried licorice extract supplement added to quadruple therapy. The primary endpoint is gastrointestinal side effects of eradication, with eradication rate and 12-month recurrence secondary.

  • Licorice permitting a lower antibiotic dose: NCT06881524 plans 374 participants comparing licorice and lotus root powder with reduced-dose amoxicillin against high-dose amoxicillin dual therapy. The primary endpoint is Helicobacter pylori eradication rate, testing whether licorice can offset antibiotic dose reduction.

  • Fermented deglycyrrhizinated licorice for early diabetic nerve damage: NCT07148804 enrolled 83 patients and reported improved nerve conduction (Massoud et al., 2026). The comparator was ordinary non-fermented deglycyrrhizinated licorice, so the effect is attributed to a fermentation-derived enzyme rather than to the extract itself.

  • The unrepeated negative ulcer trials: The two trials finding no ulcer-healing benefit (Feldman & Gilat, 1971; Engqvist et al., 1973) used the unstandardised 1970s preparation. Repeating them with a standardised flavonoid extract and endoscopic endpoints could either rehabilitate or finally close the claim.

  • Independent replication of the symptom trials: Every positive modern trial used one manufacturer’s extract (Raveendra et al., 2012; Raj et al., 2025), and two were run with that manufacturer’s staff as authors. A fully independent replication in reflux is the single result that would most strengthen or most weaken the current case.

  • Systematic surveys of product glycyrrhizin content: Independent assays finding residual glycyrrhizic acid in deglycyrrhizinated-labelled products imply that trial results may not transfer to retail material (ConsumerLab licorice and DGL review). Systematic content surveys across brands are the missing evidence.

Conclusion

Deglycyrrhizinated licorice is licorice root with its sweet, blood-pressure-raising compound largely removed, leaving an extract of the root’s other plant compounds that acts locally on the lining of the stomach and oesophagus rather than by shutting down acid. The best-supported effect is relief of heartburn, regurgitation and indigestion, shown in two controlled trials of a standardised extract using recognised symptom scales. A single controlled trial also found reduced stomach bacterial load, though suppression is not the same as clearing the infection. The older claim that it heals ulcers is genuinely conflicted: the larger and better-controlled trials of the classic preparation found nothing.

The evidence base has two visible weaknesses. Almost all of the modern positive trial work was produced by the maker of the extract being tested, sometimes with company staff as authors, and no independent group has repeated it. And the central safety premise — that removing the sweet compound removes the harm — does not hold cleanly in practice, since independent product testing keeps finding meaningful amounts of it in products labelled as having none, and a controlled study of a deglycyrrhizinated preparation still shifted sodium and potassium.

Across this evidence the variable that separates products is not the dose but how much of the sweet compound each one still contains, and the harm signal runs through potassium rather than through symptoms.

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