Licorice Root (Glycyrrhiza glabra)

Licorice root (Glycyrrhiza glabra) contains glycyrrhizin, a triterpene saponin that inhibits viral replication and modulates inflammatory responses. Clinical studies demonstrate its effectiveness in reducing COVID-19 symptoms and ICU stay duration through anti-inflammatory and antiviral mechanisms.

Origin & History

Licorice root derives from the perennial herb Glycyrrhiza glabra (Fabaceae family), native to southern Europe, parts of Asia, and the Middle East where it grows in subtropical and temperate regions. The root and rhizome are harvested, dried, and extracted using water, alcohol, or hydroalcoholic methods to produce extracts, powders, or teas, with extracts typically standardized to glycyrrhizic acid content.

Historical & Cultural Context

Glycyrrhiza glabra has been used for millennia in Traditional Chinese Medicine (as gan cao for harmonizing formulas), Ayurveda (yashtimadhu for throat/respiratory issues), and Greco-Arabic systems for cough, digestive ulcers, and liver diseases. Historical records date to ancient Egypt and China's Shennong Bencao Jing (~2000 years ago) for expectorant and anti-inflammatory purposes.

Health Benefits

• COVID-19 symptom relief: Open-label RCT showed improvements in fever, cough, and inflammatory markers within 7 days (PMID: 32933552)
• Reduced ICU stay: Double-blind RCT (n=52) found 760mg daily reduced ICU length and improved oxygen saturation in critically ill COVID-19 patients (PMID: 39262414)
• Oral ulcer healing: Systematic review of 6 trials (n≈244) demonstrated topical licorice (1-5%) reduced pain and ulcer size significantly (P<0.01) within 4-8 days
• NAFLD improvement: 12-week RCT in women showed significant improvements in ALT (p<0.001), insulin resistance, and hepatic steatosis (PMID: 35785498)
• Anti-inflammatory effects: Multiple studies confirm suppression of NF-κB, TNF-α, IL-6, and COX-2/PGE2 pathways

How It Works

Glycyrrhizin inhibits viral replication by blocking viral entry and interfering with RNA synthesis. It suppresses pro-inflammatory cytokines like IL-6 and TNF-α while inhibiting 11β-hydroxysteroid dehydrogenase, leading to cortisol-like anti-inflammatory effects. The compound also modulates NF-κB signaling pathway to reduce inflammatory responses.

Scientific Research

Clinical evidence includes a double-blind RCT (n=52) showing 760mg D-reglis® licorice tablets reduced ICU stay in COVID-19 patients (PMID: 39262414), and a systematic review of 6 trials demonstrating topical licorice's efficacy for recurrent aphthous stomatitis. An RCT in women with NAFLD found 12 weeks of licorice powder improved liver enzymes and insulin resistance (PMID: 35785498).

Clinical Summary

Open-label RCT evidence shows licorice root improves COVID-19 symptoms including fever and cough within 7 days, with measurable reductions in inflammatory markers. A double-blind RCT with 52 critically ill COVID-19 patients found 760mg daily significantly reduced ICU length of stay and improved oxygen saturation. While promising, the evidence base remains limited to COVID-19 studies with small sample sizes. Additional research is needed to establish broader therapeutic applications.

Nutritional Profile

{"macronutrients": {"carbohydrates": "53g per 100g", "protein": "0.2g per 100g", "fiber": "0.2g per 100g"}, "micronutrients": {"calcium": "91mg per 100g", "iron": "0.05mg per 100g", "magnesium": "37mg per 100g", "potassium": "37mg per 100g", "sodium": "50mg per 100g"}, "bioactive_compounds": {"glycyrrhizin": "2-25% depending on preparation", "flavonoids": "0.5-1% including liquiritin and isoliquiritin"}, "bioavailability_notes": "Glycyrrhizin is well-absorbed but can be metabolized to glycyrrhetinic acid, which may affect mineralocorticoid activity. Flavonoids have moderate bioavailability, influenced by gut microbiota."}

Preparation & Dosage

Oral: 760mg standardized extract tablets daily for acute conditions (5 days). Topical: 1-5% extract in patches or pastes applied 4 times daily for 5-8 days. Chronic conditions: Unspecified powder dose for 12 weeks. Limit glycyrrhizic acid intake to less than 100mg daily to avoid adverse effects. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Ginger root, Marshmallow root, Slippery elm, Milk thistle, N-acetylcysteine

Safety & Interactions

Licorice root can cause pseudoaldosteronism, leading to hypertension, hypokalemia, and fluid retention with prolonged use. It may interact with blood pressure medications, diuretics, and corticosteroids by potentiating their effects. Contraindicated in pregnancy due to potential premature labor risk and in patients with cardiovascular disease or kidney disorders. Daily intake should not exceed 100mg glycyrrhizin for extended periods.