Licorice root (Glycyrrhiza glabra, root and rhizome; including deglycyrrhizinated DGL)

Licorice for colds and cough appears in the EMA HMPC monograph 2013 as a «traditionally used herb», which is a regulatory category recognising 30 years of folk use, not proven clinical efficacy. Modern RCTs with hard endpoints (illness duration, complications, viral load) are absent. Cochrane has not published a systematic review of licorice root in cold or upper respiratory infection. NICE and the Spanish SEMI recommend symptomatic therapy in uncomplicated cold: paracetamol for fever, fluids, rest, humidified air; antibiotics are not indicated, antivirals only in influenza and COVID-19 in high-risk patients (oseltamivir, nirmatrelvir/ritonavir). Licorice does not appear in these recommendations. Licorice syrup in Russia is registered in GRLS as an expectorant for cough with viscous sputum for short-term use (5-7 days). EMA HMPC limits courses to 4-6 weeks and glycyrrhetinic acid intake to 100 mg/day.

Deglycyrrhizinated licorice (DGL) is actively marketed for heartburn, gastritis, reflux, and ulcer as a «natural PPI alternative». The Raveendra 2012 RCT (Evid Based Complement Alternat Med) in 50 patients with functional dyspepsia reported lower CGSRS symptom scores after 30 days of GutGard licorice root extract 150 mg/day. The sample is small, manufacturer-sponsored, without comparison to omeprazole or rebamipide. Older 1970-80s work on carbenoxolone (a semisynthetic glycyrrhetinic acid derivative) showed gastric ulcer healing, but carbenoxolone was withdrawn from most markets owing to mineralocorticoid side effects. NICE NG184 for gastro-oesophageal reflux disease recommends proton pump inhibitors (omeprazole, esomeprazole, pantoprazole, rabeprazole, lansoprazole) and H2 blockers (famotidine, nizatidine) as first-line, with alginates (Gaviscon) and antacids for symptom relief. The Spanish SEPD follows the same approach. Licorice is absent from reflux and peptic ulcer guidelines. DGL stripped of glycyrrhizin carries less hypertension risk and less benefit. If licorice was offered in place of a PPI, consider seeking a second opinion – alarm features (weight loss, dysphagia, melaena, haematemesis, anaemia) require gastroscopy, not self-treatment with licorice.

Licorice root is central to the marketing concept of «adrenal fatigue». The hypothesis: chronic stress «depletes» the adrenals, cortisol output falls, weakness, morning sluggishness, and salt cravings appear, and licorice «supports» the adrenals through 11-beta-HSD2 inhibition and prolonged endogenous cortisol action. Endocrinology has rejected this concept. The Endocrine Society Statement 2016 and the Spanish SEEN confirm: «adrenal fatigue» is not a recognised diagnosis. Chronic fatigue has other causes – iron and B12 deficiency, hypothyroidism, depression, sleep disorders, myalgic encephalomyelitis/chronic fatigue syndrome, long COVID, uncontrolled diabetes. Real adrenal insufficiency – Addison's disease, secondary hypocortisolism – is confirmed in the lab (cosyntropin test, morning cortisol, ACTH) and treated with hydrocortisone or prednisolone replacement per protocol, not with licorice root. Taking licorice for «adrenal fatigue» is dangerous: prolonged cortisol action produces hypertension and hypokalaemia and masks the actual causes of fatigue.