Licorice Root and Blood Pressure Medications: How It Can Make Your Treatment Ineffective

When you're managing high blood pressure, every pill matters. Your doctor carefully chose your medication based on your health history, lifestyle, and lab results. But what if something you're taking - something labeled as a "natural remedy" - is quietly undoing all that work? Licorice root might be one of those hidden culprits.

What’s in Licorice Root That Causes Problems?

Licorice root comes from the plant Glycyrrhiza glabra. It’s been used for thousands of years - from ancient Egyptian remedies to traditional Chinese medicine - mostly for coughs, stomach issues, and sore throats. Today, you’ll find it in teas, candies, herbal supplements, and even some cough syrups. But here’s the catch: the real licorice root contains a compound called glycyrrhizin. This isn’t just a flavoring agent. It’s a powerful substance that acts like a hormone in your body.

Glycyrrhizin tricks your kidneys into holding onto salt and water while flushing out potassium. That means more fluid in your bloodstream, which raises your blood pressure. It also messes with your body’s natural hormone balance by blocking an enzyme called 11β-hydroxysteroid dehydrogenase type 2. Normally, this enzyme keeps cortisol (a stress hormone) from acting like aldosterone (a salt-retaining hormone). When glycyrrhizin blocks it, cortisol starts behaving like aldosterone - and your blood pressure climbs.

How Much Is Too Much?

You don’t need to eat a whole bag of black licorice to run into trouble. Studies show that consuming more than 100 mg of glycyrrhizin per day for two weeks or longer can start causing problems. That’s roughly equivalent to eating 50 grams (about 1.7 ounces) of real licorice candy daily. But here’s the problem: you won’t know how much glycyrrhizin you’re getting.

Raw licorice root can contain anywhere from 2% to 24% glycyrrhizin. Commercial extracts are often standardized to 4-20%. Some supplements don’t even list the amount on the label. A 2020 study found that one product labeled "licorice root" had 10 times more glycyrrhizin than another with the same name. That kind of inconsistency makes it impossible to guess your risk.

Which Blood Pressure Medications Are Affected?

Licorice root doesn’t just raise blood pressure - it makes your medications less effective. Here’s how it interferes with common treatments:

• ACE inhibitors (like lisinopril): Effectiveness drops by 30-50%. Your body holds onto salt, which these drugs are trying to flush out.
• ARBs (like losartan): Effectiveness decreases by about 25%. The same salt-and-water retention undermines their action.
• Calcium channel blockers (like amlodipine): Blood pressure control worsens by 15-20%. Studies show patients’ readings spike within days of starting licorice.
• Potassium-sparing diuretics (like spironolactone): This is the worst combo. Licorice drains potassium, while these drugs try to keep it. The result? A dangerous imbalance that can cause heart rhythm problems and complete loss of medication effectiveness.

A 2020 case report described a patient on spironolactone whose blood pressure shot up to 210/115 mmHg after just a few weeks of licorice tea. He ended up in the hospital.

Real People, Real Consequences

You don’t have to take our word for it. Real patients have shared their stories:

• A 68-year-old man in the U.S. was doing fine on lisinopril - his blood pressure was steady at 130/80. After starting daily licorice tea, his numbers jumped to 185/105 in just 10 days.
• A Reddit user on r/HighBloodPressure noticed his systolic pressure rise by 22 points after eating black licorice candy daily. His doctor found out he’d been consuming real licorice root, not just flavored candy.
• In New Zealand, a 55-year-old man on fludrocortisone (a steroid that affects blood pressure) developed panic attacks and a systolic pressure of 210 after starting licorice supplements. He needed emergency care.

These aren’t rare cases. Over 150 documented cases worldwide link licorice root to dangerous spikes in blood pressure among people on antihypertensives. And 92% of user reports on health forums describe negative outcomes.

Not All Licorice Is the Same

Here’s something most people don’t know: Most licorice-flavored candy in the U.S. doesn’t contain real licorice root. In fact, about 95% use anise oil instead. That’s why you can eat Twizzlers and not have a problem. But if the label says "licorice extract," "Glycyrrhiza glabra," or "natural licorice flavor," you’re getting the real thing - and the real risk.

The same goes for herbal supplements. Licorice is often included in formulas for digestion, adrenal support, or immune health. Many people take them without realizing the danger. A 2018 survey found that 30% of herbal laxatives and 25% of traditional Chinese medicine formulas contain licorice root.

What Should You Do?

If you’re taking blood pressure medication, here’s what you need to do:

• Check every label. Look for "Glycyrrhiza glabra," "licorice root," or "licorice extract." If you see it, avoid it.
• Ask your pharmacist. They can check your supplements, teas, and even some cough syrups for hidden licorice.
• Don’t assume "natural" means safe. Licorice root is a plant, but that doesn’t make it harmless. It’s a potent substance with real drug-like effects.
• Consider deglycyrrhizinated licorice (DGL). This form has over 99% of glycyrrhizin removed. It’s used for stomach issues and is generally safe for people on blood pressure meds.
• Get your potassium checked. If you’ve been taking licorice, even occasionally, ask your doctor to test your potassium. Levels below 3.5 mmol/L can be dangerous, especially with diuretics.

What About the Future?

Right now, the U.S. Food and Drug Administration doesn’t require manufacturers to list glycyrrhizin content on labels. The European Union does - products with more than 10 mg per serving must carry a warning. The American Heart Association recommends avoiding all licorice root if you have high blood pressure.

There’s hope on the horizon. The FDA’s proposed Dietary Supplement Listing Act of 2023 would require companies to disclose active ingredients - including glycyrrhizin - on labels. That could make it much easier to avoid dangerous interactions.

Until then, the safest choice is simple: if you’re on blood pressure medication, skip licorice root entirely. The risk isn’t worth it. Your meds are working hard. Don’t let a sweet treat sabotage them.