Licorice root is the root of a small perennial herb native to parts of Europe, Asia, and northern Africa. It has been used in traditional medicine for thousands of years, and its primary active compound is roughly 60 times sweeter than sugar, which explains both its name (from the Greek for “sweet root”) and its popularity as a flavoring. But licorice root is far more than a candy ingredient. It contains dozens of bioactive compounds that affect everything from digestion to skin pigmentation to blood pressure.
The Plant and Its Active Compounds
Licorice belongs to the legume family, the same plant family as beans and peanuts. It grows wild across Eurasia, northern Africa, and western Asia, and is commercially cultivated in several countries. The part used medicinally is the root and underground stem, which are harvested, dried, and either sold whole or processed into extracts and powders.
The compound that gets the most attention is glycyrrhizin, a naturally occurring substance responsible for licorice’s intense sweetness. Glycyrrhizin and its breakdown product, glycyrrhetinic acid, drive most of licorice root’s biological effects, both beneficial and potentially harmful. Other notable compounds include glabridin, which has antioxidant and skin-lightening properties, and licochalcone A, which has anti-inflammatory activity. The root also contains flavonoids, plant-based estrogen-like compounds, and various other phenolics that contribute to its wide range of effects.
How It Affects the Body
Glycyrrhizin’s most significant biological action involves an enzyme that normally keeps cortisol (your body’s main stress hormone) in check within the kidneys. Licorice root blocks this enzyme, allowing cortisol to activate receptors that tell your kidneys to retain sodium and excrete potassium. In practical terms, this means licorice root can raise blood pressure, cause water retention, and lower potassium levels. In one study, patients taking glycyrrhetinic acid saw their potassium levels drop steadily over two weeks, from 5.5 to 4.5 millimoles per liter.
This mechanism is why licorice root is treated as a medicinal substance rather than a harmless herbal supplement. The same properties that make it biologically potent also make it risky in the wrong circumstances.
Digestive Uses and DGL
One of licorice root’s oldest and most studied applications is for digestive problems, particularly stomach ulcers. But here’s what makes digestive use interesting: the form that works best for the gut is one with the glycyrrhizin removed. This processed version, called deglycyrrhizinated licorice (DGL), was actually shown to be more effective at healing ulcers than the original compound, and without the blood pressure and potassium side effects.
DGL works differently from antacids or acid-blocking medications. Instead of reducing stomach acid, it strengthens the stomach’s own protective systems. It increases blood flow to damaged tissue, boosts the number of mucus-producing cells, increases the amount of mucus those cells generate, and extends the lifespan of intestinal cells. The net effect is faster healing and better protection against future damage.
There’s an important practical detail: DGL needs to mix with saliva to work. Chewable tablets taken between meals or about 20 minutes before eating are the standard approach. DGL swallowed in capsule form has not been shown to be effective, likely because it bypasses the salivary compounds that help trigger the healing response.
Skin and Cosmetic Applications
Licorice root extracts appear frequently in skincare products, particularly those targeting dark spots, melasma, and uneven skin tone. The mechanism involves blocking the enzyme tyrosinase, which your skin needs to produce melanin (the pigment responsible for skin color). By suppressing tyrosinase activity and interfering with the signaling pathways that ramp up melanin production, licorice-derived compounds can reduce hyperpigmentation over time.
The compound isoliquiritigenin, found naturally in licorice, has shown particular promise as a pigment-reducing agent. Heat-treated licorice extracts appear to have stronger antioxidant and anti-pigmentation effects than untreated versions, which is why processed licorice extracts are increasingly common in cosmetic formulations targeting brown spots, freckles, and melasma. The antioxidant activity also helps neutralize free radicals from UV exposure, adding a protective dimension beyond just lightening.
Safety Limits and Who Should Avoid It
The World Health Organization previously suggested that 100 milligrams of glycyrrhetinic acid per day would be unlikely to cause adverse effects. However, a randomized crossover trial found significant increases in blood pressure at exactly that dose, leading researchers to conclude that licorice may be more potent than previously recognized and that the safe limit may need to be lowered.
Long-term use of glycyrrhizin-containing licorice in large doses causes a well-documented syndrome that mimics the effects of excess aldosterone (a hormone that regulates salt and water balance). Symptoms include high blood pressure, low potassium, fluid retention, and suppressed levels of the body’s own aldosterone. This is not a rare or theoretical risk. It happens predictably with sustained high intake.
Certain groups face heightened danger. People with heart disease, those taking the heart medication digoxin, and anyone on diuretics that also increase potassium excretion are especially vulnerable to the potassium-lowering effects. People with high blood pressure should avoid glycyrrhizin-containing licorice entirely.
Drug Interactions
Licorice root interacts with a surprisingly wide range of medications:
- Blood thinners: Licorice can decrease the effectiveness of warfarin, increasing clotting risk.
- Blood pressure medications: It counteracts antihypertensives by promoting salt and water retention.
- Digoxin: By lowering potassium, licorice can amplify digoxin’s toxicity.
- Corticosteroids: Licorice increases the adverse effects of these drugs, likely by boosting cortisol activity through the same enzyme-blocking mechanism.
- Estrogen-based medications: It can increase or decrease estrogenic effects unpredictably.
- MAO inhibitor antidepressants: Some experts believe licorice has MAO inhibitor-like activity and could intensify side effects of these medications.
Whole Licorice vs. DGL vs. Licorice Candy
These are three very different things. Whole licorice root or full-spectrum extract contains glycyrrhizin and carries all the associated risks and benefits. DGL has had the glycyrrhizin removed, making it safer for long-term digestive use but stripping away the anti-inflammatory and antimicrobial properties tied to that compound. Most licorice candy sold in the United States contains no actual licorice at all, using anise flavoring instead. Some European and imported licorice candies do contain real licorice extract, and people have been hospitalized from eating large quantities over extended periods.
If you’re considering licorice root supplements, the distinction between glycyrrhizin-containing products and DGL is the single most important thing to understand. Your reason for using it determines which form makes sense, and the safety profiles are completely different.