Licorice

Licorice’s best human evidence is hepatic, and it is largely about glycyrrhizin given intravenously. In Japan the product Stronger Neo-Minophagen C (SNMC) has been used for chronic hepatitis C for decades; a long-term cohort reported that sustained ALT normalisation was associated with slower progression to cirrhosis and hepatocellular carcinoma ^{1Reference 1Kumada H · 2002ObservationalLong-term treatment of chronic hepatitis C with glycyrrhizin (SNMC) for preventing liver cirrhosis and hepatocellular carcinoma — cohortView study →}, and a European RCT confirmed that 4 weeks of IV glycyrrhizin lowers serum ALT in interferon non-responders ^{2Reference 2van Rossum TG et al. · 2001RCTGlycyrrhizin-induced reduction of ALT in European patients with chronic hepatitis C — randomisedView study →}. For chronic hepatitis B, a network meta-analysis of 53 RCTs and a separate systematic review/meta-analysis found glycyrrhizic-acid preparations improve liver-enzyme recovery when added to standard antivirals ^{3,4Reference 3Gao W et al. · 2023Meta-analysisComparative effectiveness of glycyrrhizic acid preparations for chronic hepatitis B liver function: a network meta-analysis of 53 RCTsView study →Reference 4Wang HN et al. · 2021Meta-analysisSystematic review and meta-analysis of Compound Glycyrrhizin Injection in chronic hepatitis B liver damageView study →}, and an open-label RCT showed corticosteroid plus glycyrrhizin produced biochemical and histological improvement in chronic drug- and herb-induced liver injury ^{5Reference 5Wang JB et al. · 2022RCTCorticosteroid plus glycyrrhizin therapy for chronic drug- or herb-induced liver injury: a randomised open-label trialView study →}. Oral whole-root data are thinner but real: two randomised trials in non-alcoholic fatty liver disease found licorice root extract lowered transaminases (ALT/AST) versus placebo alongside diet ^{6,7Reference 6Hajiaghamohammadi AA et al. · 2012RCTEfficacy of licorice root extract in decreasing transaminase activities in NAFLD: a randomised controlled trialView study →Reference 7Rostamizadeh P et al. · 2022RCTEffects of licorice root supplementation on liver enzymes, steatosis and oxidative stress in women with NAFLD: a randomised double-blind trialView study →}. The aglycone glycyrrhizic acid and 18β-glycyrrhetinic acid drive the anti-inflammatory hepatic effect.

Gap: the headline hepatitis evidence is for an injectable, purified glycyrrhizin product, not the root you drink or tincture — and that same route causes pseudo-aldosteronism ^{8Reference 8van Rossum TG et al. · 2001Observationalvan Rossum TG, et al. (2001). ‘Pseudo-aldosteronism’ induced by intravenous glycyrrhizin treatment of chronic hepatitis C patients — observational. Journal of Gastroenterology and Hepatology. https://pubmed.ncbi.nlm.nih.gov/11446888/View study →}; oral NAFLD trials are small and short.

Topical licorice is one of the better-evidenced herbal treatments for recurrent aphthous stomatitis (canker sores). A systematic review of clinical trials concluded that licorice films and rinses reduce ulcer size, pain and healing time ^{13Reference 13Dorsareh F et al. · 2023Systematic reviewTopical Licorice for Aphthous: A Systematic Review of Clinical TrialsView study →}, and a network meta-analysis of topical agents for RAS ranked licorice-containing preparations among the effective options ^{17Reference 17Liu H et al. · 2022Meta-analysisEfficacy of Topical Intervention for Recurrent Aphthous Stomatitis: A Network Meta-AnalysisView study →}. Supporting RCTs include a licorice gargle juice that cut aphthous pain on a visual-analogue scale ^{14Reference 14Liu HL et al. · 2022RCTEffective licorice gargle juice for aphthous ulcer pain relief: a randomised double-blind placebo-controlled trialView study →}, a diphenhydramine-plus-licorice solution that outperformed diphenhydramine alone ^{15Reference 15Akbari N et al. · 2020RCTEffects of licorice-containing diphenhydramine solution on recurrent aphthous stomatitis: a double-blind randomised clinical trialView study →}, and a dissolving bioadhesive patch containing glycyrrhiza extract that shrank ulcers faster than placebo by day 8 ^{16Reference 16Martin MD et al. · 2008A controlled trial of a dissolving oral patch of glycyrrhiza (licorice) extract for aphthous ulcersView study →}. The proposed mechanism is local anti-inflammatory and mucosal-coating (demulcent) action.

Gap: trials are small and use varied vehicles (patch, film, gargle, elixir); there is no standardised product or dose, and most report short follow-up.

Gargling a licorice solution before anaesthesia reduces post-operative sore throat and post-extubation cough — a genuinely replicated human finding. A double-blind RCT in 236 thoracic-surgery patients intubated with large double-lumen tubes found pre-operative licorice gargle roughly halved sore-throat incidence versus sugar-water ^{9Reference 9Ruetzler K et al. · 2013RCTA randomised, double-blind comparison of licorice versus sugar-water gargle for prevention of postoperative sore throat and postextubation coughingView study →}; an earlier randomised study in laminectomy patients reported the same direction of effect ^{10Reference 10Agarwal A et al. · 2009RCTEfficacy of licorice gargle for attenuating postoperative sore throat — randomised single-blindView study →}, and a dose-finding RCT identified an effective gargle concentration ^{11Reference 11Honarmand A et al. · 2016RCTEfficacy of different doses of liquorice gargling for attenuating postoperative sore throat and cough after tracheal intubation — randomisedView study →}. A Bayesian network meta-analysis of topical agents for preventing sore throat after single-lumen intubation included licorice among the ranked effective options ^{12Reference 12Singh NP et al. · 2020Meta-analysisEfficacy of topical agents for prevention of postoperative sore throat after single-lumen intubation: a Bayesian network meta-analysisView study →}. This is the modern, controlled expression of the herb’s traditional demulcent/expectorant use for the throat.

Gap: the benefit is shown for a pre-procedure gargle, a specific setting; it does not establish that swallowed licorice tea helps ordinary sore throats, and effect sizes are modest.

This is licorice’s classic clinical indication, and the evidence is real but old and preparation-dependent. Deglycyrrhizinated licorice (DGL) — the root with the blood-pressure-raising glycyrrhizin removed — was tested in several controlled trials for gastric and duodenal ulcer from the late 1960s onward, with endoscopic healing reported and efficacy comparable to early acid-suppressing drugs in some studies ^{18,20Reference 18Turpie AG et al. · 1969Clinical trialClinical trial of deglycyrrhizinized liquorice in gastric ulcerView study →Reference 20D’Imperio N et al. · 1978RCTDouble-blind trial in duodenal and gastric ulcers: cimetidine and deglycyrrhizinized liquorice — randomisedView study →}; DGL also reduced aspirin-induced gastric mucosal bleeding ^{19Reference 19Rees WD et al. · 1979AnimalEffect of deglycyrrhizinated liquorice on gastric mucosal damage by aspirin — animal modelView study →}. The mechanism attributed to glycyrrhetinic acid is prostaglandin-mediated: inhibition of 15-hydroxyprostaglandin dehydrogenase raises mucosal prostaglandins, increasing mucus secretion and cell proliferation — the same logic that produced the semi-synthetic drug carbenoxolone. More recently, adding licorice to standard Helicobacter pylori triple therapy improved eradication rates in two RCTs ^{21,22Reference 21Hajiaghamohammadi AA et al. · 2016RCTEffect of adding licorice to the standard treatment regimen of Helicobacter pylori — randomisedView study →Reference 22Momeni A et al. · 2014RCTEffect of licorice versus bismuth on eradication of Helicobacter pylori in peptic ulcer disease — randomisedView study →}, consistent with in-vitro data that licorice polysaccharides block H. pylori adhesion to gastric tissue ^{23Reference 23Wittschier N et al. · 2009In vitroAqueous extracts and polysaccharides from liquorice roots inhibit adhesion of Helicobacter pylori to human gastric mucosa — in vitroView study →}.

Gap: the whole-root-vs-DGL question is unresolved — one RCT found DGL ineffective, suggesting the glycyrrhizin fraction matters — and the strongest trials predate modern methodology and proton-pump inhibitors.

Three randomised trials support topical licorice for radiotherapy-induced oral mucositis in head-and-neck cancer patients. A licorice mucoadhesive film reduced mucositis severity versus placebo ^{28Reference 28Pakravan F et al. · 2021RCTEffect of Licorice Muco-adhesive Film on Radiotherapy-Induced Oral Mucositis — randomised controlled trialView study →}; a double-blind RCT found a licorice film comparable to a triamcinolone (corticosteroid) film for pain and ulceration ^{29Reference 29Ghalayani P et al. · 2017RCTTriamcinolone acetonide vs licorice mucoadhesive film on radiotherapy-induced oral mucositis: a randomised double-blinded clinical trialView study →}; and an aqueous Glycyrrhiza extract lowered the incidence/severity of mucositis when used preventively during radiotherapy ^{30Reference 30Najafi S et al. · 2017RCTPreventive Effect of Glycyrrhiza glabra Extract on Oral Mucositis in Head-and-Neck Radiotherapy: a randomised clinical trialView study →}. The effect is attributed to local anti-inflammatory and demulcent activity — the same tissue-soothing property behind the aphthous and sore-throat data.

Gap: small single-centre trials with different formulations; no large multi-centre confirmation and no effect on cancer outcomes (this is supportive care only).

Anti-inflammatory activity is the mechanistic thread that ties licorice’s local successes together, and it is well mapped at the molecular level. Licochalcone B is a specific inhibitor of the NLRP3 inflammasome, disrupting the NEK7–NLRP3 interaction ^{24Reference 24Li Q et al. · 2022In vitroLicochalcone B specifically inhibits the NLRP3 inflammasome by disrupting NEK7-NLRP3 interaction — in vitroView study →}; licorice triterpenoids and flavonoids downregulate NF-κB and COX-2 signalling and protect the intestinal barrier in models of colitis ^{25Reference 25Leite CDS et al. · 2022ReviewAnti-Inflammatory Properties of Licorice-Derived Compounds in Intestinal Disorders — reviewView study →}. Reviews of the licochalcones catalogue broad anti-inflammatory effects across cell and animal systems ^{26Reference 26Maria Pia GD et al. · 2019ReviewBiological Effects of Licochalcones — reviewView study →}. In humans, the anti-inflammatory action shows up indirectly — through the ulcer, mucositis and sore-throat trials above — rather than through dedicated systemic-inflammation endpoints.

Gap: most direct anti-inflammatory data are in vitro or in animals; there is no RCT using a validated systemic inflammatory marker (e.g. CRP) as a primary outcome.

Licorice reduces cariogenic bacteria, and this has moved into small human trials. Two systematic reviews concluded that licorice preparations (lollipops, rinses, dentifrices) reduce salivary Streptococcus mutans counts and may help prevent caries, mainly in children ^{31,32Reference 31Tharakan AP et al. · 2020Systematic reviewEffectiveness of licorice in preventing dental caries in children: a systematic reviewView study →Reference 32Nuvvula S et al. · 2020Systematic reviewEfficacy of Licorice Lollipops in Reducing Dental Caries in a Paediatric Population: a systematic reviewView study →}. A randomised clinical trial found a licorice mouthwash comparable to chlorhexidine for lowering salivary S. mutans in high-caries-risk patients ^{33Reference 33Helmy N et al. · 2021RCTEfficacy of Licorice on Salivary Streptococcus mutans vs Chlorhexidine Mouthwash in High Caries Risk Patients: a randomised clinical trialView study →}, and a clinical study of a G. uralensis lollipop containing glycyrrhizol A reduced S. mutans colonisation while preserving overall oral microbial diversity ^{34Reference 34Chen Y et al. · 2019Clinical trialLollipop containing Glycyrrhiza uralensis extract reduces Streptococcus mutans colonization and maintains oral microbial diversity in Chinese preschool children — clinical trialView study →}. A review of oro-dental applications catalogues activity against periodontal and Candida organisms as well ^{35Reference 35Messier C et al. · 2012ReviewLicorice and its potential beneficial effects in common oro-dental diseases — reviewView study →}.

Gap: endpoints are usually the bacterial surrogate (S. mutans count), not actual caries reduction over time; trials are short and small.

Licorice reproducibly lowers serum testosterone in humans — a finding that began as a safety signal and became a therapeutic lead. Armanini’s group reported a testosterone drop in healthy men ^{36Reference 36Armanini D et al. · 1999Clinical trialReduction of serum testosterone in men by licorice — clinical trialView study →}, reproduced it in a second cohort (≈26% fall after one week) ^{37Reference 37Armanini D et al. · 2003Clinical trialLicorice consumption and serum testosterone in healthy man — clinical trialView study →}, and showed the same in healthy women ^{38Reference 38Armanini D et al. · 2004Clinical trialLicorice reduces serum testosterone in healthy women — clinical trialView study →}; the effect is attributed to mild inhibition of androgen-synthesis enzymes plus the 11β-HSD/cortisol axis. In polycystic ovary syndrome, adding licorice to spironolactone offset spironolactone’s tendency to raise renin/aldosterone while contributing anti-androgen action ^{40Reference 40Armanini D et al. · 2007Clinical trialTreatment of polycystic ovary syndrome with spironolactone plus licorice — clinical trialView study →}, and a 2024 double-blind RCT found licorice extract with a low-calorie diet improved obesity, glycaemic and lipid indices in overweight women with PCOS ^{41Reference 41Hooshmandi H et al. · 2024RCTEffects of licorice extract with a low-calorie diet on obesity, glycemic and lipid indices in overweight/obese women with PCOS: a randomised, double-blind, placebo-controlled trialView study →}. Note a counter-result: a controlled study found no significant sex-steroid change at moderate liquorice doses ^{39Reference 39Sigurjonsdottir HA et al. · 2006Clinical trialLiquorice in moderate doses does not affect sex steroid hormones of biological importance — clinical trialView study →}, so the effect is dose-dependent.

Gap: the testosterone-lowering studies are small and short; PCOS trials are few, and the moderate-dose null result means the effect needs a meaningful glycyrrhizin dose — which reintroduces the blood-pressure risk.

A standardised low-glycyrrhizin extract has one good trial here. In a randomised, double-blind, placebo-controlled study, GutGard (G. glabra extract, 75 mg twice daily for 30 days) significantly reduced functional-dyspepsia symptom severity and improved quality of life versus placebo ^{27Reference 27Raveendra KR et al. · 2012RCTAn Extract of Glycyrrhiza glabra (GutGard) Alleviates Symptoms of Functional Dyspepsia: a randomised, double-blind, placebo-controlled studyView study →}. The advantage of a standardised, glycyrrhizin-reduced extract is that it aims to keep the mucosal benefit while limiting the mineralocorticoid risk.

Gap: a single manufacturer-linked RCT; needs independent replication before the effect can be considered established.

The metabolic signal is real but tied to a specific preparation — licorice flavonoid oil (LFO), a hydrophobic flavonoid fraction (rich in glabridin) in medium-chain triglycerides, not ordinary root. Human RCTs found LFO enhanced fat oxidation during light exercise ^{45Reference 45Mori N et al. · 2015RCTEnhancement of Fat Oxidation by Licorice Flavonoid Oil in Healthy Humans during Light Exercise — randomisedView study →}, reduced body weight/fat in overweight subjects ^{44Reference 44Bell ZW et al. · 2011Clinical trialEffect of dietary supplementation with licorice flavonoid oil on anthropometric and biochemical markers of health and adiposity — clinical trialView study →}, and — at 300 mg/day — increased muscle mass in older adults undergoing knee-osteoarthritis rehabilitation ^{46Reference 46Kinoshita T et al. · 2017RCTEffects of licorice flavonoid oil on increasing muscle mass: a randomised, double-blind, placebo-controlled trialView study →}. Topically, a glycyrrhetinic acid cream reduced subcutaneous thigh-fat thickness by inhibiting local 11β-HSD1 ^{47Reference 47Armanini D et al. · 2005Clinical trialGlycyrrhetinic acid can reduce the thickness of subcutaneous thigh fat through topical application — clinical trialView study →}. Animal work supports improved lipoprotein-lipase expression and insulin sensitivity with glycyrrhizic acid in high-fat-fed rats ^{48Reference 48Eu CH et al. · 2010AnimalGlycyrrhizic acid improved lipoprotein lipase expression, insulin sensitivity and lipid deposition in high-fat-diet obese rats — animal modelView study →}.

Gap: the human benefits are for LFO, a proprietary oil — they don’t transfer to licorice tea, powder or standard tincture, and trials are small.

Glycyrrhizin has striking antiviral activity in the dish. It was among the most active compounds against SARS-associated coronavirus in the 2003 Lancet screen ^{49Reference 49Cinatl J et al. · 2003In vitroGlycyrrhizin, an active component of liquorice roots, and replication of SARS-associated coronavirus — in vitroView study →}; glycyrrhizin also inhibits SARS-CoV-2 replication by blocking the viral main protease (Mpro) in vitro ^{50Reference 50van de Sand L et al. · 2021In vitroGlycyrrhizin Effectively Inhibits SARS-CoV-2 Replication by Inhibiting the Viral Main Protease — in vitroView study →}, and semi-synthetic glycyrrhizic-acid derivatives are markedly more potent than the parent ^{51Reference 51Hoever G et al. · 2005In vitroAntiviral activity of glycyrrhizic acid derivatives against SARS-coronavirus — in vitroView study →}. A systematic review of glycyrrhizin preparations for the earlier SARS and MERS epidemics found supportive but low-quality clinical evidence ^{52Reference 52Li H et al. · 2020Systematic reviewThe Potential of Glycyrrhizinate in the Management of COVID-19: a systematic review of glycyrrhizin preparations in SARS and MERSView study →}. This mechanistic antiviral action overlaps the hepatitis-C/B benefit above, where the effect is on the virus-inflamed liver rather than viral clearance.

Gap: essentially all direct antiviral data are in vitro or in silico; there is no controlled oral-licorice trial for any acute viral infection, and effective concentrations may not be reachable by ingestion.

This is the herb’s signature mechanism, well proven in humans but poorly validated as a treatment. Glycyrrhetinic acid inhibits 11β-hydroxysteroid dehydrogenase, the enzyme that inactivates cortisol to cortisone; inhibition raises local and circulating active cortisol, an effect shown to persist for weeks after dosing stops, with renin–aldosterone suppression lasting months ^{56Reference 56Whorwood CB et al. · 1993AnimalLicorice inhibits 11β-hydroxysteroid dehydrogenase mRNA levels and potentiates glucocorticoid hormone action — animal modelView study →}. Herbalists use this “cortisol-sparing” action as an adrenal tonic and to help taper corticosteroid drugs. The pharmacology is genuine; what is missing is any trial showing that this improves a defined clinical state such as fatigue.

Gap: “adrenal fatigue” is not a validated diagnosis and has never been an RCT endpoint for licorice; the very mechanism invoked here is also the one that causes hypertension and hypokalaemia, so the therapeutic window is narrow.

Antioxidant activity is a consistent property of licorice flavonoids — glabridin in particular is a documented free-radical scavenger — but dedicated human evidence is scarce. The clearest human read-out is indirect: the NAFLD RCT in women reported improvement in oxidative-stress markers alongside liver enzymes ^{7Reference 7Rostamizadeh P et al. · 2022RCTEffects of licorice root supplementation on liver enzymes, steatosis and oxidative stress in women with NAFLD: a randomised double-blind trialView study →}, and reviews summarise radical-scavenging and lipid-peroxidation-lowering effects across preclinical systems ^{43,68Reference 43Asl MN et al. · 2008ReviewReview of pharmacological effects of Glycyrrhiza sp. and its bioactive compounds — reviewView study →Reference 68Wahab S et al. · 2021ReviewGlycyrrhiza glabra (Licorice): a comprehensive review on its phytochemistry, biological activities, clinical evidence and toxicology — reviewView study →}.

Gap: almost entirely constituent-level and in vitro; no trial uses a validated systemic oxidative-stress panel as a primary outcome for whole licorice.

One randomised trial addresses this. In 60 postmenopausal women, licorice reduced the frequency and severity of hot flashes over the treatment period, compared against hormone-replacement therapy ^{53Reference 53Menati L et al. · 2014RCTEvaluation of licorice effects on reducing hot flashes in postmenopausal women — randomisedView study →}. The rationale is the phytoestrogenic isoflavonoid content (glabridin, formononetin) of the root.

Gap: a single small trial that compared licorice to HRT rather than placebo, limiting causal strength; no confirmation and unclear durability.

Glabridin is a tyrosinase inhibitor, the enzymatic basis of skin-lightening/anti-hyperpigmentation activity, and licorice extract is widely used cosmetically for this. Recent work identified the active depigmenting components of G. glabra extract and mapped the CRTC1/MITF pathway they inhibit ^{63Reference 63Liu J et al. · 2025In vitroGlycyrrhiza glabra extract as a skin-whitening agent: active components and CRTC1/MITF pathway inhibition — in vitroView study →}, and a transdermal delivery system was engineered specifically to get poorly-soluble glabridin across the skin barrier for anti-hyperpigmentation use ^{64Reference 64He J et al. · 2023In vitroTetrahedral framework nucleic acid loaded with glabridin: a transdermal delivery system for anti-hyperpigmentation — in vitroView study →}. Related preclinical work shows glabridin and licochalcones calm inflammatory skin conditions such as atopic dermatitis via TLR4/NF-κB downregulation ^{65Reference 65Chang J et al. · 2021AnimalGlabridin attenuates atopic dermatitis progression via TLR4/MyD88/NF-κB downregulation — animal modelView study →}.

Gap: evidence is in-vitro and delivery-focused; glabridin’s poor skin penetration is a real limit, and there are no controlled clinical depigmentation trials of a defined licorice product here.

The traditional use of licorice in mood formulas has a plausible but purely preclinical mechanism. Licorice isoflavans and isoflavenes — chiefly glabridin — inhibited serotonin reuptake in vitro in a dose-dependent way resembling oestradiol, while the isoflavones genistein and daidzein were largely inactive ^{54Reference 54Ofir R et al. · 2003In vitroInhibition of serotonin re-uptake by licorice constituents — in vitroView study →}; separately, licorice constituents (glycyrrhisoflavone and the coumarin licocoumarone) were flagged as human MAO-B inhibitors in a high-throughput screen ^{55Reference 55Mazzio E et al. · 2013In vitroHigh throughput screening to identify natural human monoamine oxidase B inhibitors — in vitroView study →}.

Gap: in-vitro constituent findings only — no animal behavioural model and no human trial; unknown whether these compounds reach relevant brain concentrations after oral dosing.

Licorice compounds show antiproliferative activity in cell lines, but this remains far from clinical. A novel licorice-root polyphenol induced apoptosis, G2/M cell-cycle arrest and Bcl-2 phosphorylation in tumour cell lines ^{67Reference 67Rafi MM et al. · 2002In vitroNovel polyphenol molecule from licorice root induces apoptosis, G2/M arrest and Bcl-2 phosphorylation in tumor cell lines — in vitroView study →}, and reviews of the licochalcones document mechanisms — EGFR/ERK, PI3K/Akt/mTOR, pro-apoptotic and anti-angiogenic — across many cancer models ^{66Reference 66Deng N et al. · 2023ReviewAnticancer effects of licochalcones: a review of the mechanisms — reviewView study →}.

Gap: entirely in vitro/mechanistic; no human anticancer data. This is a research direction, not a use.

Licorice is safe as an occasional food and flavouring, but its main saponin, glycyrrhizin, inhibits the enzyme 11β-hydroxysteroid dehydrogenase and so produces a dose- and duration-dependent pseudo-aldosteronism: sodium and water retention, raised blood pressure, potassium loss (hypokalaemia) and suppression of the renin–aldosterone system. A systematic review and meta-analysis confirmed that consistent ingestion of glycyrrhizin-containing licorice raises blood pressure and lowers plasma potassium ^{57Reference 57Penninkilampi R et al. · 2017Meta-analysisThe association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysisView study →}, and case reports document severe hypertension, hypokalaemia, oedema, muscle weakness and cardiac arrhythmia with chronic or high-dose use ^{58,60Reference 58Ceccuzzi G et al. · 2023ReviewLiquorice Toxicity: A Comprehensive Narrative ReviewView study →Reference 60Awad N et al. · 2020Case reportLicorice-induced apparent mineralocorticoid excess causing persistent hypertension and hypokalemia — case reportView study →}.

Licorice should be avoided by people with hypertension, heart failure, kidney disease, low potassium, or cholestatic liver disease. Clinically important drug interactions are pharmacodynamic: potassium-depleting diuretics (thiazides, loop) add to the hypokalaemia; digoxin toxicity is potentiated by low potassium; corticosteroids are potentiated (licorice prolongs cortisol’s half-life); and antihypertensive drugs are antagonised. It also reproducibly lowers serum testosterone, a consideration for men and for anyone monitoring androgen levels ^{36,38Reference 36Armanini D et al. · 1999Clinical trialReduction of serum testosterone in men by licorice — clinical trialView study →Reference 38Armanini D et al. · 2004Clinical trialLicorice reduces serum testosterone in healthy women — clinical trialView study →}. As a practical mitigation, deglycyrrhizinated licorice (DGL) removes most of this risk — but also loses part of the systemic activity. Regulatory guidance limits sustained glycyrrhizin intake to roughly ≤100 mg/day and therapeutic use to short courses (~4–6 weeks) unless supervised.

Scope note: pharmacodynamic (mineralocorticoid/potassium) interactions are well documented; formal pharmacokinetic (CYP-level) interaction studies of whole licorice are limited, so a specific CYP interaction is not asserted here. Lactation has not been specifically studied — treat as not established.