Licorice root extract, derived from the Glycyrrhiza glabra plant, affects the body’s stress hormone, cortisol. This relationship involves interference with cortisol’s natural deactivation process, not direct stimulation of the adrenal glands. A specific compound in licorice root is responsible for this effect, which can lead to changes in fluid balance and blood pressure. Understanding this biological link is important for anyone using licorice root in confectionery, herbal teas, or dietary supplements.
The Specific Mechanism of Cortisol Elevation
The scientific explanation for licorice’s effect lies with its main active component, glycyrrhizin (glycyrrhizic acid). Once ingested, the gut metabolizes glycyrrhizin into its active form, glycyrrhetinic acid. This metabolite acts as a competitive inhibitor against a specific enzyme found primarily in the kidneys: 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2).
The 11β-HSD2 enzyme naturally protects mineralocorticoid receptors in the kidneys from being overwhelmed by cortisol. It does this by rapidly converting active cortisol into its biologically inactive form, cortisone, before cortisol can bind to the receptor. When glycyrrhetinic acid inhibits this enzyme, cortisol deactivation is prevented. This allows higher concentrations of active cortisol to reach and bind to the mineralocorticoid receptors.
Cortisol and the mineralocorticoid hormone aldosterone bind to the mineralocorticoid receptor with similar effectiveness. Since cortisol concentration is naturally much higher than aldosterone, inhibiting 11β-HSD2 allows cortisol to act as a potent mineralocorticoid. This increases cortisol activity at the tissue level, mimicking the effects of excessive aldosterone, a condition termed pseudoaldosteronism. The result is an increase in the lifespan and activity of existing cortisol, leading to an elevation of its effects in sensitive tissues.
Health Consequences of Cortisol Increase
The mineralocorticoid activity induced by licorice leads to predictable physiological changes, driven by the kidneys’ response to receptor over-activation. This activation promotes increased reabsorption of sodium and water from the renal tubules back into the bloodstream. This retention of sodium and fluid directly drives hypertension, or high blood pressure.
Fluid retention (edema) is a visible outcome, often appearing around the ankles and face. The kidney’s mechanism for retaining sodium also involves increased excretion of potassium into the urine. This leads to hypokalemia, or low potassium levels, a serious condition. Hypokalemia can cause muscle weakness, fatigue, and may precipitate dangerous cardiac arrhythmias, especially in those with pre-existing heart conditions.
Continuous activation of these receptors suppresses the body’s system for regulating blood pressure and fluid balance. This suppression is evident by a decrease in plasma levels of renin and aldosterone. This confirms the symptoms are caused by an external agent mimicking aldosterone. These effects are collectively known as apparent mineralocorticoid excess syndrome and can occur even with modest doses of licorice over time.
Consumption Levels and Monitoring
The amount of licorice required to trigger these effects varies widely, but scientific data suggests a threshold exists for adverse reactions. For healthy adults, consuming more than 100 milligrams of glycyrrhizic acid daily for several weeks is associated with increased blood pressure and a drop in plasma potassium. This amount of glycyrrhizin can be found in as little as 50 grams of licorice confectionery, though the concentration varies significantly between products.
Regulatory bodies have suggested a maximum safe daily intake of 100 to 200 milligrams of glycyrrhizin for the general population. High-risk groups, such as those diagnosed with hypertension, heart disease, or kidney problems, are more sensitive and should avoid licorice entirely. Given the potential for severe side effects, including hypertensive crisis and cardiac events, medical monitoring is advisable for regular users with pre-existing health concerns.
It is important to differentiate between true licorice root products and deglycyrrhizinated licorice (DGL). DGL products are processed to remove the majority of glycyrrhizin, the compound responsible for the mineralocorticoid effects. DGL is considered safe for long-term use because the active compound has been largely eliminated. Consumers seeking the beneficial properties of licorice without the risk of elevated cortisol activity should choose DGL alternatives.