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 people with hypertension and an enlarged heart. It lowers vascular tone, reduces aldosterone, and helps the kidneys release sodium and water. Licorice root works against that goal through a separate hormonal pathway.
- Licorice is converted to its active form. Glycyrrhizin in licorice root is converted in the gut to glycyrrhetinic acid, the compound responsible for the interaction.
- A kidney enzyme is blocked. Glycyrrhetinic acid inhibits 11-beta-hydroxysteroid dehydrogenase type 2, the enzyme that normally deactivates cortisol before it can reach the mineralocorticoid receptor in the kidney.
- Cortisol starts acting like aldosterone. With the enzyme blocked, cortisol stimulates the receptor as if it were aldosterone. The kidneys retain sodium and water, blood pressure rises, and potassium is excreted in greater amounts. Doctors call this apparent mineralocorticoid excess, or pseudoaldosteronism.
- The two effects collide. Losartan is trying to lower blood pressure by blocking the angiotensin II signal; licorice is pushing it back up by mimicking aldosterone. The effects partially cancel out, and the net result depends on how much licorice is consumed.
Why is this important?
Meaningful licorice exposure can blunt the blood-pressure-lowering effect of an ARB by a clinically relevant amount. 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.
The potassium loss caused by licorice can also produce symptomatic low potassium (hypokalemia). Symptoms include muscle weakness, cramps, fatigue, constipation, and palpitations. Published case reports document severe hypertension together with profound hypokalemia and prolonged QT on the ECG after heavy glycyrrhizin intake, which in vulnerable people, especially older adults or those with underlying heart disease, can predispose to dangerous heart-rhythm problems. This is why the combination is treated seriously rather than as a minor dietary footnote.
The effect is dose-dependent, and the threshold is easy to cross without realizing it: a few pieces of imported black licorice candy, a couple of cups of licorice tea, or regular use of an herbal formula can each add up over days to weeks.
What should you do?
Before changing anything: take an honest inventory of licorice-containing products in your diet and supplement routine. Read ingredient lists for Glycyrrhiza glabra, licorice root, licorice extract, or glycyrrhizin. Many products use anise flavoring, which tastes like licorice but contains no glycyrrhizin and is safe, so the label is what matters. Bring this list to your doctor or pharmacist before making changes, especially if your blood pressure has been higher than expected.
Every day while on losartan: treat real licorice root and glycyrrhizin-containing products as ingredients to avoid. If you use licorice for digestive support, gastric comfort, or upper-respiratory relief, switch to deglycyrrhizinated licorice (DGL), which has had the glycyrrhizin removed and is not flagged for blood pressure interactions.
After stopping licorice: recheck your blood pressure after a week or two, since the effect takes time to wash out. Your clinician may also want to check your serum potassium, because hypokalemia from licorice can take weeks to resolve and is worth confirming before assuming things are back to normal. Watch for weakness, cramps, or palpitations in the meantime and report them.
Which specific products are affected?
Black licorice candy is the most common source of meaningful glycyrrhizin exposure in Western countries; imported brands tend to contain more than mass-market candies, but the amount varies 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, and chewing tobacco and pipe tobacco can be flavored with it as well.
Deglycyrrhizinated licorice (DGL) products are clearly labeled, have had the glycyrrhizin largely removed, and are considered the safer alternative with losartan when used as directed. Anise-flavored products are look-alikes only and contain no glycyrrhizin.
The science behind it
The Merck Manual Professional describes licorice's glycyrrhizin as causing sodium and water retention, hypertension, and potassium loss through pseudoaldosteronism, noting that this can reduce the effectiveness of antihypertensive drugs and that low-glycyrrhizin (DGL) preparations avoid the effect.
Human case reports anchor the severity. One published case report (PMC6935715) documented licorice-induced pseudohyperaldosteronism presenting with severe hypertension, very low potassium (around 1.9 mmol/L), and a prolonged QT interval. Another case report (PMC5882392) described a hypertensive crisis with target-organ injury attributed to glycyrrhizin. As individual case reports they describe what can happen in susceptible people rather than how often it occurs, but they confirm that the mechanism opposing ARB action is not just theoretical and can reach a dangerous degree in real patients.
Frequently Asked Questions
Does anise have the same effect as licorice?
No. Anise shares the licorice flavor but contains no glycyrrhizin, so it does not affect blood pressure or potassium. Only real licorice root (Glycyrrhiza glabra) carries the interaction.
Is deglycyrrhizinated licorice (DGL) safe with losartan?
DGL has had the glycyrrhizin largely removed and is not flagged for blood pressure interactions. It is the safer choice if you use licorice for digestive comfort, when used as directed.
How much licorice is too much?
There is no safe amount to assume, because sensitivity and product strength vary. Regular daily intake of black licorice candy, licorice tea, or an herbal formula containing it is enough to matter for some people. The safest approach on losartan is to avoid glycyrrhizin-containing licorice and discuss any use with your pharmacist.
How would I know if licorice is affecting me?
The two signals are blood pressure creeping up despite taking your medication, and symptoms of low potassium such as muscle weakness, cramps, fatigue, or palpitations. If either appears, review your licorice exposure and tell your clinician.
If I stop licorice, how soon will things improve?
Blood pressure and potassium do not normalize instantly. Rechecking after a week or two is reasonable, and potassium in particular can take weeks to recover, so confirm with your clinician rather than assuming.
Should I stop my losartan instead?
No. Do not stop or change your prescribed medication on your own. The fix is removing the licorice, not adjusting losartan; any medication change should be made with your doctor.
Key takeaways
- Licorice raises blood pressure and lowers potassium through pseudoaldosteronism, working directly against losartan.
- Severe cases in published reports have included dangerously low potassium and abnormal heart rhythm, which is why this pairing is taken seriously.
- Avoid black licorice candy, licorice root tea, and herbal products containing glycyrrhizin while on losartan; anise is fine, and DGL is the safer alternative.
- If your blood pressure has crept up unexpectedly, check your licorice exposure before assuming the medication has stopped working, and review your products with your doctor or pharmacist.