Licorice (Glycyrrhiza glabra) has been traditionally used to support the adrenal cortex and overall adrenal function, but there is also scientific evidence for its effects on the hypothalamic-pituitary-adrenal (HPA) axis. The active compound in licorice, glycyrrhizin, inhibits the enzyme 11β-hydroxysteroid dehydrogenase type 2, which leads to increased cortisol availability in the body by preventing its breakdown. This mechanism has been studied in both animal and human models, demonstrating that licorice can prolong the biological half-life of endogenous cortisol. This is relevant to adrenal insufficiency or fatigue, as higher cortisol levels may help support the body’s response to stress.

Clinical research, including small human trials and case studies, supports the use of licorice in certain cases of adrenal insufficiency, though the quality and quantity of evidence is limited. Notably, excessive intake of licorice can cause pseudoaldosteronism, leading to hypertension, hypokalemia, and other side effects due to increased mineralocorticoid activity. Therefore, while the scientific rationale exists and some studies support its use, the evidence is not robust or universally accepted, and long-term or high-dose use is not recommended without medical supervision.

In summary, licorice’s use for adrenal support is justified by both tradition and scientific mechanisms, but the clinical evidence is moderate (rated 3), and safety concerns necessitate caution.