Licorice root, derived from the Glycyrrhiza glabra plant, has been used as a flavoring agent and herbal remedy for centuries. Consuming this substance can lead to a measurable increase in blood pressure. This effect is not immediate but is a cumulative biological process that unfolds over time. Understanding the compound and the timeline of its action clarifies how quickly this dietary item impacts cardiovascular health.
The Active Compound and Physiological Mechanism
The primary component responsible for licorice’s effect on blood pressure is glycyrrhizin, or glycyrrhizic acid (GA). Once ingested, this compound is metabolized in the gut into its active form, glycyrrhetinic acid (GA). This metabolite then targets a specific enzyme in the body, which initiates the hypertensive effect.
Glycyrrhetinic acid works by inhibiting the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11-HSD2), which is located primarily in the kidneys. The natural function of 11-HSD2 is to convert the stress hormone cortisol into its inactive form, cortisone. By blocking this conversion, GA causes a localized buildup of active cortisol within the renal collecting tubules.
This excess cortisol then binds to the mineralocorticoid receptors in the kidney, which typically respond to the hormone aldosterone that regulates salt and water balance. The resulting effect is known as pseudoaldosteronism, mimicking having too much aldosterone. This leads to the retention of sodium and water, increasing overall fluid volume, and simultaneously causing an excessive loss of potassium (hypokalemia). The increase in fluid volume and subsequent vasoconstriction directly cause the elevated blood pressure.
Consumption Thresholds and Onset Timeline
Blood pressure rise depends on the amount of glycyrrhizin consumed and the consistency of the intake. Research suggests that a daily intake of 100 milligrams of glycyrrhizic acid is sufficient to cause a measurable rise in blood pressure in healthy adults. This amount is considered the upper limit deemed safe by international health organizations for most individuals.
This 100-milligram threshold can be met by consuming as little as 50 grams of licorice candy, depending on its concentration of the active compound. Studies show that a significant rise in systolic blood pressure can occur after two weeks of consuming 50 to 200 grams of licorice daily. The effect is cumulative, building up over a period of days to weeks rather than occurring immediately after a single instance of consumption.
In a controlled study, blood pressure readings began to show increases from the fifth day of consistent 100-milligram daily intake and continued to rise over the two-week period. This sustained exposure is required for the effects to manifest as hypertension. Individuals who already have pre-existing hypertension or heart conditions are more sensitive to the effects of licorice and may experience a larger rise in blood pressure.
Physical Symptoms and Reversal Time
Physical signs related to mineralocorticoid excess often accompany the rise in blood pressure. Common symptoms include fluid retention, which may present as edema or swelling, and persistent headaches. The excessive loss of potassium can lead to hypokalemia, causing symptoms like muscle weakness, lethargy, or muscle cramps.
In severe cases, hypokalemia can prompt serious complications, including metabolic alkalosis and dangerous changes to heart rhythm, such as a prolonged QT interval. Once licorice consumption is stopped, the body’s enzyme function gradually recovers, and the effects are fully reversible. Most patients see their blood pressure and electrolyte levels return to normal within one to two weeks after complete abstinence.
In some situations, the full resolution of symptoms, particularly severe ones, may require up to three weeks for the body’s chemistry to completely rebalance. Treatment may involve temporary potassium supplementation to correct the imbalance and manage the cardiovascular symptoms while the body naturally clears the glycyrrhetinic acid.