What happens when you take lisinopril with licorice?
Lisinopril is an ACE inhibitor that lowers blood pressure by blocking the renin-angiotensin-aldosterone system. Real licorice root works against it through a separate hormonal pathway. Here is the sequence:
- Glycyrrhizin is converted in the body. Licorice root contains glycyrrhizin (glycyrrhizic acid), which after digestion becomes glycyrrhetinic acid.
- A protective kidney enzyme is blocked. Glycyrrhetinic acid inhibits 11-beta-hydroxysteroid dehydrogenase type 2, the enzyme that normally inactivates cortisol in the kidney so it cannot activate the mineralocorticoid receptor.
- Cortisol starts acting like aldosterone. With the enzyme blocked, cortisol switches on the mineralocorticoid receptor, producing a state called pseudoaldosteronism.
- The kidneys retain sodium and water and dump potassium. This pushes blood pressure up and pulls serum potassium down.
- The two effects oppose lisinopril. Lisinopril is trying to lower blood pressure and tends to nudge potassium up; licorice does the reverse on both counts, so regular licorice intake can blunt the medication's effect.
Why is this important?
The link between regular licorice intake and higher blood pressure with lower potassium is consistent across the published evidence, including a systematic review and meta-analysis. The effect is dose-related: the more glycyrrhizin consumed and the longer it is taken, the larger the change. People who already have high blood pressure or who take antihypertensive medication tend to react at lower amounts than healthy volunteers.
This interaction is easy to miss. Blood pressure can drift upward on a stable lisinopril dose, and the natural assumption is that the medication has stopped working rather than that a candy or herbal tea is overriding it. Heavy, sustained licorice use has been associated in case reports with severe consequences such as marked hypertension and kidney injury, but most everyday exposures are far milder. The more common, practical problem is gradually rising blood pressure and falling potassium.
Low potassium matters on its own. It can cause muscle weakness, fatigue, cramps, and palpitations, and in severe cases can contribute to dangerous heart rhythm problems. Because lisinopril tends to raise potassium while licorice lowers it, stopping or starting licorice can also produce confusing potassium swings that make monitoring harder.
What should you do?
The core principle is simple: treat real licorice as an ingredient to avoid while you take lisinopril, and verify any blood pressure or potassium changes with your clinician rather than self-adjusting your medication.
Before changing anything: Take an honest inventory of what you consume. Read labels on candies, teas, herbal tinctures, throat lozenges, and traditional remedies, looking for licorice root, Glycyrrhiza glabra, Glycyrrhiza uralensis, glycyrrhizin, or glycyrrhizic acid. Note that many products labeled "licorice flavor" in the US use anise oil and contain no glycyrrhizin.
Every day: Skip black licorice candy made with real extract, licorice root teas, and herbal blends that list licorice. If you use licorice for digestion, switch to deglycyrrhizinated licorice (DGL), which has the glycyrrhizin removed and is not associated with the blood pressure and potassium effects.
After a change: If your blood pressure has been creeping up on a stable lisinopril dose, stop the licorice and ask your doctor or pharmacist about rechecking your blood pressure, and a potassium check, after a couple of weeks. The pseudoaldosterone effect takes time to wear off, so do not expect an instant return to baseline, and do not change your lisinopril dose on your own.
Which specific products are affected?
Black licorice candy made with real licorice extract is the most common source of meaningful glycyrrhizin, especially imported European brands such as Panda, RJ's, and Dutch dropjes. Licorice root tea, including blends marketed for digestion, adrenal support, or hormone balance, frequently contains a real amount.
Less obvious sources include herbal cough drops and throat sprays with licorice root, traditional Chinese herbal formulas that include licorice root (gancao) as a balancing ingredient, licorice extract in some laxative and diuretic herbal blends, certain bitters and amari used in cocktails, and some chewing and pipe tobaccos flavored with licorice. Traditional formulas are best reviewed with a herbalist or clinician familiar with them.
Safer choices include deglycyrrhizinated licorice (DGL) products, which are clearly labeled DGL and have had the glycyrrhizin removed, and US licorice-flavored candies made with anise oil rather than real licorice.
The science behind it
A systematic review and meta-analysis by Penninkilampi and colleagues (J Hum Hypertens, 2017; PMID 28660884) pooled studies of consistent licorice ingestion and found a statistically significant rise in systolic blood pressure and a fall in serum potassium, confirming a dose-related effect.
The mechanism, pseudohyperaldosteronism from glycyrrhizin's inhibition of 11-beta-HSD2, is described in detail in a review by Sabbadin, Bordin and colleagues (Licorice: From Pseudohyperaldosteronism to Therapeutic Uses, Front Endocrinol, 2019). The Merck Manual Professional Edition entry on licorice states plainly that glycyrrhizin causes sodium and water retention, hypertension, and hypokalemia, and that it can diminish the effectiveness of antihypertensive drugs, which is the basis for caution with an ACE inhibitor like lisinopril.
Frequently Asked Questions
Is licorice-flavored candy in the US a problem?
Often not. Many American "licorice" candies are flavored with anise oil and contain no glycyrrhizin. The concern is products made with real licorice extract, which are more common in imported black licorice. Check the ingredient list.
Is DGL safe with lisinopril?
Deglycyrrhizinated licorice has the glycyrrhizin removed, so it is not associated with the blood pressure and potassium effects that drive this interaction. It is generally considered a safer option for digestive support, but mention it to your pharmacist if you are unsure.
How much licorice is too much?
There is no single safe number, and people on blood pressure medication tend to react at lower amounts than healthy people. Because the effect is cumulative and dose-related, the practical answer is to treat regular real-licorice intake as something to avoid and discuss your specific situation with your doctor or pharmacist.
Could licorice be why my blood pressure went up?
It is worth considering. If your blood pressure has risen on a stable lisinopril dose and you have been eating black licorice or drinking licorice tea, that is a plausible contributor. Stop the licorice and review the change with your clinician rather than assuming the medication failed.
Does the effect go away quickly after I stop?
No. The pseudoaldosterone effect can take a couple of weeks or longer to fully resolve, and potassium may take time to normalize. Recheck with your clinician rather than expecting an immediate change.
Do I need a potassium test?
If you have been consuming licorice regularly, a potassium check after stopping is reasonable, especially if you have had symptoms like muscle weakness or palpitations. Your doctor or pharmacist can advise based on your history.
Key takeaways
- Real licorice raises blood pressure and lowers potassium through pseudoaldosteronism, working against lisinopril.
- The effect is dose-related and confirmed by a meta-analysis; people on blood pressure medication react at lower amounts.
- Avoid black licorice candy made with real extract, licorice root tea, and herbal blends listing licorice.
- US "licorice" candies often use anise oil and contain no glycyrrhizin; check labels.
- Use DGL instead if you need licorice for digestion.
- If your blood pressure has risen unexpectedly, audit your licorice intake and review blood pressure and potassium with your doctor or pharmacist rather than adjusting lisinopril yourself.