What happens when you take losartan with licorice?
Losartan is an angiotensin II receptor blocker (ARB) used to treat high blood pressure, protect the kidneys in diabetes, and reduce stroke risk in hypertensive patients with left ventricular hypertrophy. It works by blocking the angiotensin II type 1 receptor, which lowers vascular tone, reduces aldosterone, and helps the kidneys release sodium and water.
Licorice root contains glycyrrhizin, which the body converts to glycyrrhetinic acid in the gut. That metabolite inhibits an enzyme in the kidney (11-beta-hydroxysteroid dehydrogenase type 2) whose normal job is to deactivate cortisol before it can stimulate the mineralocorticoid receptor. When the enzyme is blocked, cortisol behaves like aldosterone: the kidneys retain sodium and water, blood pressure rises, and potassium is excreted in greater amounts. The medical term for this is apparent mineralocorticoid excess or pseudoaldosteronism.
The collision with losartan is direct. Losartan is trying to lower blood pressure by blocking the angiotensin II signal. Licorice is raising it by mimicking aldosterone. The two effects partially cancel out, with the net result depending on doses of each.
Why is this important?
Reports and reviews suggest that meaningful licorice exposure can reduce the blood-pressure-lowering effect of ARBs by a clinically relevant amount. Some clinical accounts describe a roughly 25% loss of blood pressure control when patients on ARBs add regular licorice consumption. From the patient's perspective, this looks like the medication has stopped working - readings drift upward, sometimes with intermittent spikes - even though the cause is dietary rather than pharmacologic.
Beyond the blood pressure effect, the potassium loss caused by licorice can produce symptomatic hypokalemia. Symptoms include muscle weakness, cramps, fatigue, constipation, and palpitations. In severe cases, low potassium predisposes to dangerous cardiac arrhythmias, especially in older adults or those with underlying heart disease.
The interaction has documented dose dependence. Healthy volunteer studies have shown systolic blood pressure increases of 3 to 14 mmHg with licorice intake equivalent to 75 to 540 mg of glycyrrhetinic acid daily for two to four weeks. In real-world settings the doses are highly variable: a few pieces of imported black licorice candy daily, a couple of cups of licorice tea, or regular use of an herbal formula can each cross the threshold for measurable effect.
What should you do?
If you take losartan, treat licorice root and glycyrrhizin-containing products as ingredients to avoid. Check labels on candies, teas, herbal supplements, and traditional remedies. Many products use anise flavoring rather than real licorice (anise has the licorice taste but no glycyrrhizin), so reading the ingredient list matters - look for Glycyrrhiza glabra, licorice root, licorice extract, or glycyrrhizin.
If your blood pressure has been higher than expected, take an honest inventory of licorice-containing products. Stopping licorice and rechecking blood pressure after one to two weeks is a reasonable first step. Your clinician may also want to check serum potassium, since hypokalemia from licorice can take weeks to resolve and is worth confirming before assuming things are back to normal.
For people who use licorice for digestive support, gastric ulcers, or upper respiratory comfort, deglycyrrhizinated licorice (DGL) is a safer alternative. DGL has had the glycyrrhizin removed during processing, retaining the soothing flavonoids without the mineralocorticoid effects. DGL is widely available in chewable tablet form and is not flagged for blood pressure interactions.
Which specific products are affected?
Black licorice candy is the most common source of meaningful glycyrrhizin exposure in Western countries. Imported brands tend to have higher glycyrrhizin content than mass-market American licorice candies, but quantities vary widely. Licorice root tea - sold in many herbal blends for digestion, hormone balance, or adrenal support - is another frequent source.
Herbal cough drops, throat lozenges, and traditional respiratory remedies often include licorice root. Traditional Chinese herbal formulas commonly include licorice (gancao) and should be reviewed with a knowledgeable herbalist. Some bitters, amari, and herbal liqueurs use licorice extract for flavor. Chewing tobacco and pipe tobacco can be flavored with licorice extract as well.
Deglycyrrhizinated licorice (DGL) products are clearly labeled and contain less than 2% glycyrrhizin. These are considered safe with losartan when used as directed.
The bottom line
Licorice raises blood pressure and lowers potassium through pseudoaldosteronism, working directly against losartan. Avoid black licorice candy, licorice root tea, and herbal products containing glycyrrhizin while on losartan. Use DGL if you need licorice for digestive support. If your blood pressure has been creeping up unexpectedly, check your licorice exposure before assuming the medication has stopped working.