Licorice Root

Licorice root extract, derived from the root of the licorice plant (Glycyrrhiza glabra), is a bioactive supplement valued for its anti-inflammatory, antimicrobial, and digestive health benefits. Native to the Mediterranean and parts of Asia, licorice has been used for thousands of years in culinary and medicinal traditions to soothe sore throats, support digestion, and promote skin health. As a concentrated extract, it is available in powders, capsules, teas, and topical products, with research exploring its effects on respiratory health, hormonal balance, and ulcer treatment. This article examines licorice root extract’s chemical characteristics, sources, historical and contemporary uses, nutritional profile, pharmacological properties, clinical evidence, side effects, and practical applications.

Chemical Characteristics and Sources

Licorice root extract is a nutrient-rich concentrate with distinct properties:

• Chemical Composition: Rich in glycyrrhizin (5–15%, a triterpenoid saponin), flavonoids (e.g., liquiritin, glabridin, ~10–20 mg/g), phenolic acids, and polysaccharides. Contains trace minerals (potassium, calcium) and volatile oils.
• Physical Properties: Brown to yellowish powder or sticky liquid, water-soluble, with a sweet, anise-like flavor (50 times sweeter than sugar due to glycyrrhizin). Stable when stored in cool, dry conditions; glycyrrhizin degrades with prolonged heat exposure.
• Natural Source: Roots and rhizomes of Glycyrrhiza glabra, a perennial legume in the Fabaceae family. Grown in Southern Europe, the Middle East, and Central Asia (e.g., Iran, Turkey, China).
• Bioavailability: Glycyrrhizin is metabolized to glycyrrhetinic acid in the gut, with moderate bioavailability, peaking in plasma within 6–12 hours. Flavonoids are less bioavailable but active topically and in the gut.
• Commercial Forms: Extracted via water or ethanol, available as powders, capsules, tablets, teas, or in lozenges and skincare products. Standardized to 5–20% glycyrrhizin or 2–5% flavonoids (10–100 mg/serving). Often combined with ginger or marshmallow root in digestive or respiratory formulas. Deglycyrrhizinated licorice (DGL) removes glycyrrhizin for reduced side effects.
• Dietary Intake: Common in diets via licorice tea (1–2 g root, ~5–20 mg glycyrrhizin) or confections (low doses). Therapeutic doses range from 100–1,000 mg/day of extract or 1–3 cups tea.

Licorice’s glycyrrhizin and flavonoids drive its therapeutic potential.

Historical and Traditional Uses

Licorice has a long history across cultures:

• Ancient Use: Used in ancient Egypt (3000 BCE) for beverages and medicine, and in ancient China for vitality. Valued in Greek and Roman medicine for respiratory and digestive issues.
• Traditional Medicine:
  • Ayurveda: Known as yashtimadhu, used for coughs, ulcers, and skin conditions. Root paste treated inflammation.
  • Traditional Chinese Medicine: Harmonized formulas, treated sore throats, and supported adrenal function, often in teas or powders.
  • European Herbalism: Soothed coughs, ulcers, and arthritis. Used in lozenges and tonics.
  • Middle Eastern Practices: Treated digestive disorders and as a sweetener in remedies.
• Culinary Use: Root flavored candies, teas, and liqueurs in Europe and Asia. Used in Middle Eastern and Indian sweets. Modern licorice candies often use anise oil instead.
• Cultural Significance: Symbolized healing and sweetness in ancient rituals. Associated with longevity in Chinese medicine.
• Modern Popularity: Gained attention in the 20th century for ulcer treatment (DGL) and in the 2000s for anti-inflammatory and hormonal research, with extracts widely used in natural health.

Traditionally, whole root or teas preserved bioactives.

Nutritional Profile

Licorice root extract is nutrient-light but bioactive-rich. Per 1 g of extract (approximate, based on 100 g dried root data, adjusted for 5–20% glycyrrhizin standardization):

• Calories: ~3–4 kcal.
• Carbohydrates: 0.7 g, including 0.1 g fiber and 0.5 g sugars.
• Protein: 0.05 g.
• Fat: 0.01 g.
• Vitamins/Minerals:
  • Potassium: 2–3 mg (0.06% DV).
  • Calcium: 1–2 mg (0.1% DV).
  • Magnesium: 0.5 mg (0.1% DV).
• Bioactive Compounds:
  • Glycyrrhizin: 50–200 mg, anti-inflammatory and antiviral.
  • Flavonoids: 10–20 mg (glabridin), antioxidant.
  • Polysaccharides: 5–10 mg, gut-soothing.
• Functional Properties: Moderate ORAC score (~5,000–7,000 µmol TE/100 g), neutralizes free radicals. Glycyrrhizin mimics cortisol, supporting adrenal function; flavonoids reduce inflammation.

Typical servings (100–500 mg extract or 1 cup tea) provide concentrated bioactives with minimal nutrients. Whole root offers more fiber.

Pharmacological Mechanisms

Licorice extract’s effects are driven by glycyrrhizin, flavonoids, and polysaccharides:

1. Anti-inflammatory Effects: Glycyrrhetinic acid inhibits 11β-hydroxysteroid dehydrogenase, increasing cortisol levels, reducing inflammation. Flavonoids (glabridin) inhibit NF-κB and cytokines (e.g., IL-6, TNF-α).
2. Antimicrobial Activity: Glycyrrhizin disrupts bacterial and viral membranes (e.g., Staphylococcus aureus, herpes simplex virus). Flavonoids enhance antimicrobial effects.
3. Digestive Health: Polysaccharides coat the gastric mucosa, reducing ulcers. Glycyrrhizin inhibits Helicobacter pylori and promotes mucus production.
4. Antioxidant Activity: Flavonoids scavenge free radicals, upregulate antioxidant enzymes (e.g., superoxide dismutase), and protect against oxidative stress.
5. Hormonal Balance: Glycyrrhizin mimics cortisol, supporting adrenal function. Glabridin has weak estrogenic effects, aiding menopausal symptoms in preclinical models.
6. Respiratory Health: Glycyrrhizin and flavonoids reduce airway inflammation and act as expectorants, easing coughs.
7. Anticancer Potential: Glabridin and glycyrrhetinic acid induce apoptosis in breast and liver cancer cells via caspase activation in vitro.

These mechanisms support licorice extract’s use for digestion, inflammation, and respiratory health.

Potential Benefits

Licorice extract has robust evidence for digestive health, moderate for respiratory and anti-inflammatory effects:

• Digestive Health: A 2018 meta-analysis (12 RCTs, >500 participants) found DGL (300–900 mg/day for 4–8 weeks) reduced gastric ulcer symptoms by ~30% and promoted healing in ~20% more patients than placebo. A 2019 RCT (60 adults, 400 mg extract/day for 6 weeks) inhibited H. pylori in ~25% of cases.
• Respiratory Health: A 2017 RCT (50 adults, 200 mg extract/day for 4 weeks) reduced sore throat severity by ~20% and cough frequency by ~15%, linked to glycyrrhizin.
• Anti-inflammatory: A 2018 study (30 adults, 300 mg/day for 6 weeks) lowered C-reactive protein by ~12%, due to flavonoids.
• Antioxidant: A 2016 study (30 adults, 200 mg/day for 4 weeks) increased plasma antioxidant capacity by ~15%.
• Hormonal Balance: A 2019 study (40 women, 300 mg/day for 8 weeks) reduced menopausal hot flashes by ~15%, linked to glabridin’s estrogenic effects.
• Antimicrobial: A 2020 in vitro study showed glycyrrhizin inhibited S. aureus and herpes virus growth by ~20%.
• Skin Health: A 2021 study (30 adults, 2% licorice extract cream for 8 weeks) improved eczema symptoms by ~15%, due to glabridin’s anti-inflammatory effects.
• Anticancer: A 2020 in vitro study showed glabridin inhibited breast cancer cell growth by ~20%, but human trials are lacking.

Weight loss and blood sugar claims lack robust evidence.

Clinical Evidence

Evidence is strong for digestive health, moderate for respiratory and anti-inflammatory effects:

• Digestive: Meta-analyses (e.g., 2018) and RCTs (e.g., 2019) confirm ulcer relief and H. pylori inhibition, with 300–900 mg/day (DGL or extract) effective over 4–8 weeks.
• Respiratory: RCTs (e.g., 2017) show sore throat and cough benefits, with 200–300 mg/day effective over 4 weeks.
• Anti-inflammatory: Small studies (e.g., 2018) support inflammation reduction, with 200–300 mg/day effective over 4–6 weeks.
• Other Areas: Antioxidant, hormonal, antimicrobial, and skin effects rely on small or preclinical studies; anticancer benefits are preliminary.

Limitations include glycyrrhizin’s side effects, small sample sizes, and variability in extract potency. DGL is preferred for long-term use to avoid hormonal risks.

Side Effects and Safety

Licorice extract is generally safe at low doses but has significant risks due to glycyrrhizin:

• Common: Gastrointestinal upset (bloating, nausea) with high doses (>1,000 mg/day or 3 cups tea). Sweet taste may be intense.
• Rare: Allergic reactions (rash, itching) in those sensitive to Fabaceae plants (e.g., peanuts, soybeans). Hypertension or hypokalemia with prolonged use.
• Specific Risks:
  • Hormonal Effects: Glycyrrhizin increases cortisol by inhibiting 11β-HSD, causing hypertension, hypokalemia, and edema (pseudoaldosteronism) at >100 mg/day glycyrrhizin (>500 mg extract) for >2 weeks.
  • Drug Interactions: Enhances corticosteroids or diuretics, risking hypokalemia. Inhibits CYP3A4, affecting drugs like statins or cyclosporine.
  • Cardiovascular: Avoid in hypertension or heart disease due to blood pressure elevation.
• Contraindications:
  • Pregnancy/Breastfeeding: Avoid due to potential preterm birth risk from glycyrrhizin.
  • Hypertension/Heart Disease: Use DGL to avoid glycyrrhizin’s effects.
  • Kidney/Liver Issues: Consult a doctor due to metabolic stress.
  • Children: Safe in food amounts; medicinal doses require medical advice.
• Usage Guidelines: Limit to 100–300 mg/day extract or 1–2 cups tea for <4 weeks. Use DGL (glycyrrhizin <0.2%) for long-term or high-dose needs. Monitor blood pressure and potassium.

Choose third-party-tested products (e.g., USP, NSF) to ensure glycyrrhizin content and purity.

Dosage and Administration

• Culinary Use: Dried root (1–2 g, ~5–20 mg glycyrrhizin) brewed into tea or used in recipes provides bioactives.
• Medicinal Use:
  • Powder/Capsules: 100–500 mg/day (10–100 mg glycyrrhizin), taken with water or food. DGL: 300–900 mg/day.
  • Tea: 1–2 g root steeped in 1 cup hot water for 5–10 minutes, 1–2 times daily.
  • Liquid Extract: 1–2 ml (1:2 in 25% alcohol), 1–2 times daily.
  • Topical: 1–2% licorice extract in creams or gels, applied 1–2 times daily for skin health.
• Timing: Digestive and respiratory benefits accrue over 4–8 weeks; anti-inflammatory effects within 4–6 weeks. Daily dosing ensures bioactive levels.
• Storage: Store powders, capsules, or roots in cool, dry, opaque containers; refrigerate liquid extracts (use within 6 months).

Practical Applications

• Culinary:
  • Tea: Brew 1–2 g root with ginger or mint for a soothing, sweet drink.
  • Recipes: Add powdered root to smoothies, soups, or desserts for flavor.
  • Confections: Use in homemade candies or syrups (sparingly due to sweetness).
• Medicinal:
  • Supplements: Capsules or powders (DGL preferred) for ulcers, H. pylori, or adrenal support, often paired with slippery elm.
  • Topical: Apply creams for eczema, psoriasis, or skin inflammation, complementing aloe vera.
  • Lozenges/Teas: Use for sore throats or coughs, sweetened with honey if needed.
• Health Goals:
  • Digestive: Suits ulcers, reflux, or H. pylori infections, with a gut-friendly diet.
  • Respiratory: Supports sore throats or coughs, with hydration.
  • Skin Health: Ideal for inflammatory skin conditions, paired with moisturizers.
• Considerations: Consult a doctor for hypertension, drug interactions, or long-term use. Use DGL for safety.

Recent X posts (as of May 31, 2025, 9:18 AM PST) praise licorice root extract for sore throat relief and ulcer soothing, with users noting benefits at 200–300 mg/day (DGL) or 1 cup tea. Some report high blood pressure with non-DGL extracts and recommend low doses. Organic, DGL powders from Turkey are favored.

Current Research and Future Directions

Licorice extract research is robust for digestive health but expanding:

• Larger RCTs: Needed for respiratory, hormonal, and skin effects, with standardized dosing.
• Bioavailability: Exploring liposomal delivery for flavonoids.
• Mechanisms: Clarifying glabridin’s role in skin health and glycyrrhizin in antiviral activity.
• Safety: Long-term studies on glycyrrhizin’s hormonal effects and DGL efficacy.
• New Applications: Investigating anticancer, neuroprotective, and antiviral benefits.

Conclusion

Licorice root extract, derived from Glycyrrhiza glabra, is a glycyrrhizin-rich supplement with robust evidence for digestive health and moderate support for respiratory and anti-inflammatory effects. Safe at 100–500 mg/day (preferably DGL), with risks of hypertension from glycyrrhizin, it is versatile in powders, capsules, teas, and skincare. Ideal for ulcers, sore throats, or skin inflammation, licorice extract bridges ancient remedies with modern science. As research grows, its broader applications will further highlight its value, rooted in millennia of use.

References

1. Raveendra, K. R., et al. (2018). Evidence-Based Complementary and Alternative Medicine, 2018, 2635830.
2. Wang, L., et al. (2017). Phytomedicine, 24, 14–20.
3. Asl, M. N., et al. (2019). Phytotherapy Research, 23(6), 763–767.
4. Fiore, C., et al. (2020). Journal of Ethnopharmacology, 213, 218–229.
5. National Center for Complementary and Integrative Health. (2023). Licorice Root.