Licorice Root

Glycyrrhiza glabra

Family: Fabaceae Part used: Root

Key Compounds

• Glycyrrhizin
• Glycyrrhizinic acid
• 18β-glycyrrhetinic acid
• Liquiritin
• Isoliquiritin
• Liquiritigenin
• Glabridin
• Glabrene
• Licoricidin
• Formononetin
• Licoricone
• Polysaccharides

Traditional Use

• Classical kampo medicine — 甘草 (kanzo) appears in approximately half of all classical kampo formulas as a harmonising agent (調和薬); officially approved as a kampo crude drug in the Japanese Pharmacopoeia; one of the most used herbs in the Japanese national health insurance formulary
• Traditional Chinese medicine — 甘草 (gancao) described in the *Shennong Bencao Jing* (1st century CE) as superior class medicine; used in over half of all classical TCM formulas; considered to harmonise and moderate the effects of other herbs in a formula
• Ayurvedic medicine — *Yashtimadhu* (stick honey) used for throat conditions, digestive disorders, and as a general tonic in Ayurvedic practice for over 3,000 years
• Gastric protection — glycyrrhizin derivatives inhibit prostaglandin metabolism in the gastric mucosa, contributing to ulcer protection; clinical evidence for gastric and duodenal ulcer healing; WHO monograph supports use for gastric and duodenal ulcer treatment
• Respiratory demulcent — traditional use for soothing irritated airways, productive cough, and respiratory infections across Ayurvedic, Chinese, European, and Middle Eastern traditional medicine
• DGL (deglycyrrhizinated licorice) — form developed specifically to retain gastric protective activity while removing glycyrrhizin, which causes pseudoaldosteronism; widely used for gastric ulcer prevention with improved safety profile

Licorice root appears in approximately half of all classical kampo formulas.

Not because half the conditions require licorice. Because in the classical herbal framework of Chinese and Japanese medicine, licorice performs a function that is difficult to replace: it harmonises. It moderates potent herbs. It smooths formulas. It was understood for a long time in practical terms before anyone could explain the mechanism, and when the mechanism was identified — glycyrrhizin extending cortisol’s half-life by inhibiting its deactivating enzyme — it was sufficiently interesting that researchers spent decades studying it.

Most licorice candy in Western markets does not contain licorice. It contains anise, which happens to have a similar flavour. This is one of those facts that is more interesting the more you think about it. The actual root tastes like sweet earth. It does not taste like candy.

Meet the plant

A perennial herb, 1–1.5 metres tall, with pinnate leaves and small purple to blue-violet flowers. It is a legume — in the same family as peas, beans, and clover — which is not immediately obvious. The root is the medicinal part; it is harvested after 3–5 years of growth, when the glycyrrhizin content is highest.

The genus name is from Greek: glykys (sweet) + rhiza (root). The name exists because the root is sweet. Glycyrrhizin, the primary active compound, is approximately 50 times sweeter than sucrose.

The most used herb in kampo

The Shennong Bencao Jing — the foundational Chinese herbal pharmacopoeia, compiled approximately 1st century CE — classifies licorice in the superior category. The superior herbs are those appropriate for long-term daily use: non-toxic, tonifying, suitable for health maintenance. Licorice earned this classification and it persisted through 2,000 years of subsequent scholarship.

In Japanese kampo, 甘草 (kanzo) has the same status. It appears in the classical formula Shakuyaku-kanzo-to (芍薬甘草湯, peony and licorice), in Kanzo-bushi-to, in Ogi-kenchu-to, in dozens of others. The pattern is consistent enough that kampo herbalists developed a shorthand expectation: unless there is a specific reason not to include it, licorice probably belongs in the formula.

The harmonising function has a pharmacological explanation. Glycyrrhizin metabolises to 18β-glycyrrhetinic acid, which inhibits 11β-hydroxysteroid dehydrogenase — the enzyme that converts cortisol to inactive cortisone in kidney tissues. By inhibiting this enzyme, glycyrrhizin extends cortisol’s biological half-life. This produces anti-inflammatory effects and modulates the immune response. It also, if used in large amounts over long periods, causes pseudoaldosteronism. The classical herbalists who identified licorice as a harmonising agent were observing a real effect. They did not know what cortisol was.

The problem with long-term use

Glycyrrhizin is the compound that makes licorice effective and the compound that causes the primary safety concern.

Pseudoaldosteronism — the clinical syndrome from extended high-dose use — looks like excess aldosterone: sodium retention, potassium loss, water retention, elevated blood pressure. In severe cases, cardiac arrhythmia. The mechanism is clean and understood: cortisol, no longer deactivated by 11β-HSD2, activates aldosterone receptors it normally does not reach.

The dose and duration required vary significantly between individuals. Some people show effects within weeks of moderate intake; others tolerate higher doses for longer without problems. People with hypertension, heart disease, kidney disease, or those taking diuretics, corticosteroids, or cardiac medications have substantially elevated risk.

This is why DGL exists. Deglycyrrhizinated licorice was developed specifically to retain the gastric protective properties — which reside primarily in the flavonoid fraction — while removing glycyrrhizin. The problem was identified precisely enough that a solution could be engineered. The solution works reasonably well for gastric applications. It removes the problem compound, which also removes some of the activity.

The chemistry

Glycyrrhizin is the defining compound — a triterpenoid saponin present at 2–25% of dry root weight. It is responsible for the sweetness (50× sucrose), the anti-inflammatory activity, the antiviral activity, and the pseudoaldosteronism risk.

Flavonoids — liquiritin, isoliquiritin, liquiritigenin, glabridin, and others — contribute antioxidant and anti-inflammatory activity independently of glycyrrhizin. These are retained in DGL preparations.

Glabridin is an isoflavone with particular research interest for skin pigmentation — it inhibits tyrosinase, the enzyme involved in melanin synthesis, and has been incorporated into topical formulations.

What people actually do with it

In kampo (the most common form in Japan): Licorice is dispensed as part of classical formulas through kampo practitioners and some regular physicians, covered by Japan’s national health insurance. If you have been given a kampo formula and you do not know its ingredients, there is roughly a 50% chance it contains licorice.

Root decoction: 3–10 g of dried root simmered in water for 20–30 minutes. Mildly sweet, earthy, pleasant. Used traditionally for sore throat, digestive discomfort, respiratory conditions.

DGL tablets: Chewed before meals for gastric protection. The standard form for people who want licorice’s gastric properties without glycyrrhizin’s cardiovascular effects. Used for gastric ulcer protection, GERD symptom management.

Extract in formulas: Licorice extract appears in herbal formulas as a harmoniser, improving taste and moderating other ingredients. This is traditional practice in both Chinese herbal medicine and European herbalism.

Topical (glabridin): Licorice extract is found in skincare products aimed at reducing hyperpigmentation — the tyrosinase-inhibiting activity of glabridin is the basis.

Could you grow this yourself?

Technically yes. Practically, it requires patience.

Licorice is a Mediterranean and Central Asian plant that needs full sun, well-drained soil, and warm summers. It grows in parts of Japan — southern Honshu, Kyushu, and Okinawa can provide adequate conditions. The root is harvested after 3–5 years of growth, which is a significant commitment. The plant spreads by rhizomes and can become persistent once established.

Japan does not commercially cultivate licorice at significant scale. Most kanzo in the Japanese market is imported from China, Central Asia, and Afghanistan. Home cultivation is possible but the yield and quality will vary. For consistent medicinal use, the commercially processed product is more reliable.

Licorice root (甘草) in Japan

Licorice root does not have a dramatic story in Japan. It has a quiet, pervasive presence.

As 甘草 (kanzo), it is the most statistically common ingredient across the classical kampo formulary. It appears in prescriptions dispensed by a substantial proportion of Japanese doctors through the NHI system — kampo is integrated into mainstream Japanese medicine in a way unusual among developed countries. If you have received medical treatment in Japan and the doctor offered a kampo option, licorice was probably in it.

The flavour is present in Japanese traditional confectionery and in certain preparations for sore throats and colds — the sweet root was used as a home remedy long enough that its use became normalised. Licorice-flavoured throat lozenges and candies (甘草キャンディ) are available at pharmacies, though the intense connection to confectionery is stronger in Scandinavia and the Netherlands.

The high-profile research use of licorice is pharmaceutical rather than food-based: glycyrrhizin intravenous preparations were developed in Japan (Stronger Neo-Minophagen C, a glycyrrhizin-containing IV treatment) for chronic hepatitis, approved and used widely in Japanese hospitals from the 1970s onward. This medical tradition is distinct from either kampo or supplement use.

Things you’re probably wondering

Why does licorice candy not taste like licorice? Most Western licorice candy is flavoured with anise, which has a similar anethole-based flavour. Real licorice root tastes sweet and earthy — distinctly different from the candied version.

What is pseudoaldosteronism? A syndrome caused by extended high-dose glycyrrhizin use: sodium retention, potassium loss, elevated blood pressure, possible cardiac arrhythmia. Caused by glycyrrhizin’s metabolite inhibiting the enzyme that deactivates cortisol. Risk increases with dose, duration, and pre-existing cardiovascular or kidney conditions.

What is DGL? Deglycyrrhizinated licorice — processed to remove glycyrrhizin while retaining the flavonoid fraction. Useful for gastric applications where you want the demulcent and mucosal-protective properties without the pseudoaldosteronism risk.

Why is licorice in so many kampo formulas? Because it functions as a harmoniser — moderating potent ingredients and smoothing formulas. The mechanism involves glycyrrhizin extending cortisol activity. Classical practitioners observed this effect for 2,000 years before the mechanism was identified.

Where can you find it in Japan? Through kampo prescriptions at many Japanese hospitals and clinics (covered by NHI). As dried root at kampo pharmacies and TCM dispensaries. As standardised extract capsules at supplement retailers. In many over-the-counter kampo preparations.

Botanical details

The full compound list

See Also

• Ashwagandha — adaptogen sharing the stress-axis modulation; often combined with licorice in adrenal support protocols
• Eleuthero — the other major adaptogen with historical use in post-stress recovery
• Codonopsis — the other most-used qi tonic in kampo; frequently combined with licorice in classical formulas

References

• Glycyrrhiza Species (Licorice). WHO Monographs on Selected Medicinal Plants, Vol. 1. Geneva: WHO, 1999.
• Isbrucker, R.A. & Burdock, G.A. (2006). Risk and safety assessment on the consumption of licorice root (Glycyrrhiza sp.). Regulatory Toxicology and Pharmacology, 46(3), 167–192.
• Furusawa, J. et al. (2011). Glycyrrhizin and glycyrrhizinic acid: Two immune regulators with pleiotropic effects. Phytotherapy Research, 25(11), 1600–1614.
• Kim, J.K. et al. (2018). Licorice (Glycyrrhiza uralensis) flavonoids as anti-inflammatory agents. International Journal of Molecular Sciences, 19(9), 2545.
• Möller, M. et al. (2017). Glycyrrhizin in classical and new formulations. Journal of Ethnopharmacology, 196, 1–15.