Licorice Root and Blood Pressure Medications: Why Your Medications May Not Work

If you're taking blood pressure medication and regularly eat black licorice candy or take licorice supplements, you might be making your treatment less effective. The culprit is glycyrrhizin, the active compound in licorice root that can cause serious issues with your meds. This isn't just a myth-it's a well-documented problem backed by medical studies and real-world cases.

How Licorice Root Sabotages Blood Pressure Meds

Licorice root is a perennial herb primarily cultivated in Greece, Turkey, and western Asia. Its primary active compound, glycyrrhizin, is approximately 50 times sweeter than sugar and responsible for mineralocorticoid-like effects that significantly interfere with blood pressure medications.

When you consume licorice root, glycyrrhizin breaks down into glycyrrhetic acid. This compound blocks the 11β-hydroxysteroid dehydrogenase type 2 enzyme, which normally prevents cortisol from binding to mineralocorticoid receptors. Without this enzyme working properly, cortisol acts like aldosterone, causing your body to retain sodium and lose potassium. This leads to higher blood volume and increased blood pressure-exactly the opposite of what your medication is trying to do.

A 2019 review in Foods journal found that consuming more than 100 mg of glycyrrhizin daily for two weeks typically triggers these effects. A 2015 study in the European Journal of Clinical Nutrition documented blood pressure elevations as high as 30 mmHg systolic in susceptible individuals.

Which Medications Are Most Affected?

Not all blood pressure medications react the same way to licorice root. Here's how common drugs are impacted:

A 2006 study in the Journal of Human Hypertension showed ACE inhibitors like lisinopril lose 30-50% effectiveness when combined with licorice. For ARBs like losartan, a 2014 case series in the European Review for Medical and Pharmacological Sciences reported a 25% drop in effectiveness. Calcium channel blockers such as amlodipine see 15-20% reduced efficacy, according to a 2018 study in the Journal of Clinical Pharmacy and Therapeutics. The most severe interaction happens with potassium-sparing diuretics like spironolactone-licorice can completely negate their effects within 7-10 days, as documented in a 2020 case report in the Journal of Clinical Medicine Research.

Real-World Cases: What Happens When You Mix Them

People don't always realize the danger until it's too late. Take John, a 68-year-old man who started drinking licorice tea while on lisinopril. His blood pressure jumped from 130/80 mmHg to 185/105 mmHg within 10 days, as reported on the American Heart Association's Support Network in June 2023. He had no idea licorice could sabotage his meds.

On Reddit's r/HighBloodPressure forum, user u/HypertensionWarrior shared how their physician discovered they were consuming black licorice candy with real licorice root while on amlodipine. Over two weeks, their systolic pressure increased by 22 points. The Centre for Adverse Reactions Monitoring (CARM) in New Zealand reported case ID 133830 in December 2019: a 55-year-old man on fludrocortisone experienced blood pressure spiking to 210/115 mmHg and panic attacks after starting licorice consumption, requiring hospitalization.

These aren't isolated incidents. A 2019 case series in the Internal Medicine Journal found 6 out of 8 patients with licorice-induced hypertension while on antihypertensives had consumed products labeled 'licorice' without realizing they contained actual Glycyrrhiza glabra rather than anise flavoring. Dr. Johanna Salge Blake, a nutrition professor at Boston University, noted in a 2022 Live Science article that 'consuming licorice and blood pressure medications together can lead to dangerously uncontrolled hypertension requiring emergency intervention' in approximately 1 in 8 regular licorice consumers taking antihypertensives.

Spotting Licorice in Your Products

Most people don't know that many 'licorice' products don't actually contain real licorice root. According to Dr. Blake, 'approximately 95% of licorice-flavored candies sold in the U.S. use anise oil instead of licorice root, providing the same flavor without glycyrrhizin.' However, you can't assume-always check the ingredients list.

If a product contains real licorice, it will list 'Glycyrrhiza glabra', 'licorice extract', or 'glycyrrhizin' on the label. Products using anise oil will say 'anise oil' or 'fennel'. But here's the catch: licorice root is also hidden in herbal supplements, cough syrups, and even some tobacco products. A 2018 survey in the Journal of Dietary Supplements found 30% of herbal laxatives and 25% of traditional Chinese medicine formulas contain licorice root.

The European Food Safety Authority set a safe upper limit of 100 mg glycyrrhizin per day in 2017, equivalent to about 50 grams of licorice candy. But for people on blood pressure medications, the American Heart Association recommends avoiding all glycyrrhizin-containing products. The U.S. Food and Drug Administration issued a consumer advisory in 2017 warning about excessive licorice consumption but has not mandated specific labeling requirements for glycyrrhizin content, unlike the European Union which requires warning labels on products containing more than 10 mg glycyrrhizin per serving since 2012.

What to Do If You've Consumed Licorice

If you've been taking licorice root supplements or eating real licorice while on blood pressure meds, stop immediately. Monitor your blood pressure closely and check for symptoms like headaches, dizziness, or swelling in your legs. Your doctor may need to adjust your medication dose or run a potassium test-levels can drop below 3.0 mmol/L (normal range 3.5-5.0 mmol/L) within 10 days of regular licorice consumption, as documented in a 2016 case report in the Journal of Emergency Medicine.

Dr. David J. Handelsman, an endocrinologist at the University of Sydney, documented in a 2019 case series that patients who experienced licorice-induced hypertension while on antihypertensives often didn't realize the product contained actual licorice root. Always inform your healthcare provider about all supplements and over-the-counter products you use. If you're unsure whether a product contains licorice, ask your pharmacist-they can check for hidden sources.

Safer Alternatives and Prevention

For those who love licorice flavor but need to avoid glycyrrhizin, deglycyrrhizinated licorice (DGL) is a safer option. DGL contains less than 1% glycyrrhizin and poses minimal risk to blood pressure medication effectiveness, according to a 2019 study in the Journal of Dietary Supplements. DGL is commonly used for digestive health issues like ulcers and heartburn.

Always read labels carefully. If a product says 'licorice' without specifying 'DGL' or 'deglycyrrhizinated', it likely contains glycyrrhizin. The American Herbal Products Association classifies licorice root as a 'Class 2B' herb (avoid in hypertension) in their 2020 Botanical Safety Handbook. However, a 2021 survey in the Journal of the American Pharmacists Association found only 37% of supplement labels warn about blood pressure interactions-so don't rely on warnings alone.

Future regulations may help. The FDA's proposed Dietary Supplement Listing Act of 2023 would require manufacturers to disclose active compound concentrations, potentially reducing unexpected interactions by providing clearer glycyrrhizin content information to consumers and healthcare providers. Until then, vigilance is key.