Licorice Root and Blood Pressure Medications: Why Your meds May Stop Working

Ever wondered why your blood pressure won’t drop, even though you’re taking your meds every day? It might not be your dose. It could be something you’re eating-or drinking-without realizing it. Licorice root, a common ingredient in teas, candies, and herbal supplements, can quietly sabotage your blood pressure treatment. And the effects aren’t subtle. They can push your systolic pressure up by 30 points in just two weeks.

How Licorice Root Interferes with Blood Pressure Drugs

Licorice root isn’t just a sweet treat. It contains a compound called glycyrrhizin, which behaves like a mineralocorticoid hormone-mimicking aldosterone. This hormone tells your kidneys to hold onto sodium and water while flushing out potassium. The result? More fluid in your bloodstream, higher blood volume, and rising pressure.

That’s bad news if you’re on blood pressure medication. Most of these drugs work by relaxing blood vessels, reducing fluid, or blocking hormones that raise pressure. Licorice root does the exact opposite. It undoes their work.

Studies show glycyrrhizin blocks an enzyme called 11β-hydroxysteroid dehydrogenase type 2. Normally, this enzyme protects your body from cortisol (a stress hormone) overstimulating your blood pressure pathways. When it’s blocked, cortisol acts like aldosterone. And that’s when your blood pressure starts climbing-despite your pills.

Which Medications Are Most Affected?

Not all blood pressure drugs are equally vulnerable. But the ones most at risk are the ones you’d expect:

• ACE inhibitors (like lisinopril): Effectiveness drops by 30-50%. The body holds onto sodium, countering the drug’s ability to widen arteries.
• ARBs (like losartan): Around 25% loss in effectiveness. These block angiotensin, but licorice bypasses that pathway entirely by flooding the system with fluid.
• Calcium channel blockers (like amlodipine): Blood pressure control worsens by 15-20%. Even though these relax arteries, extra fluid volume still pushes pressure up.
• Potassium-sparing diuretics (like spironolactone): This is the worst combo. Licorice drains potassium while these drugs try to keep it. The result? Dangerous electrolyte imbalances, muscle weakness, and even heart rhythm problems.

One 2020 case report described a patient on spironolactone whose blood pressure spiked to 210/115 mmHg after just 10 days of licorice tea. He ended up in the ER. This isn’t rare.

How Much Licorice Is Too Much?

You don’t need to eat a whole bag. The threshold is surprisingly low.

Consuming more than 100 mg of glycyrrhizin daily for two weeks is enough to trigger effects. That’s roughly 50 grams of real licorice candy-about two standard packs. But here’s the catch: not all licorice is the same.

Raw licorice root contains 2-24% glycyrrhizin. Supplements? They can be standardized to 4-20%. Some teas, lozenges, and herbal formulas contain concentrated extracts. A single serving of certain herbal cough syrups or digestive supplements can deliver 50-100 mg in one dose.

And the effects don’t disappear when you stop. Glycyrrhizin lingers. Its metabolites can keep disrupting your electrolytes for up to two weeks after you quit.

What You’re Probably Eating (Without Knowing)

Most people assume licorice-flavored candy is just flavoring. In the U.S., about 95% of black licorice candy uses anise oil-not real licorice root. So if you’re eating Twizzlers or Red Vines, you’re probably fine.

But if you see Glycyrrhiza glabra, licorice extract, or licorice root on the label, you’re getting glycyrrhizin. That includes:

• Herbal teas labeled as “licorice root tea”
• Traditional Chinese medicine formulas (30% contain licorice)
• Herbal laxatives (25% contain licorice)
• Dietary supplements for digestion, immunity, or adrenal support
• Some cough syrups and throat lozenges
• European-style licorice candy (especially from the Netherlands, Sweden, or Finland)

Dr. David Handelsman from the University of Sydney found that 6 out of 8 patients in his study didn’t realize they were consuming real licorice. They thought they were just eating “flavored” candy.

Real People, Real Consequences

Online forums are full of stories like this:

• A 68-year-old man in Australia started drinking licorice root tea daily for “digestive relief.” His blood pressure jumped from 130/80 to 185/105 in 10 days while on lisinopril. His doctor had to change his meds.
• A Reddit user on r/HighBloodPressure reported a 22-point rise in systolic pressure after eating licorice candy daily for two weeks while on amlodipine. His doctor found the cause only after asking about his snacks.
• New Zealand’s adverse drug monitoring center documented a 55-year-old man on fludrocortisone who developed panic attacks and a 210/115 mmHg reading after starting licorice supplements.

On PatientsLikeMe, 92% of 84 posts about licorice and blood pressure meds described worsening symptoms. Seventeen cases required emergency visits. Not one reported improvement.

What Should You Do?

If you’re on blood pressure medication:

1. Check every label. Look for “Glycyrrhiza glabra,” “licorice root,” or “licorice extract.” Avoid them.
2. Ask your pharmacist. Many herbal supplements, even those labeled “natural,” contain licorice. Ask if your multivitamin, adrenal support formula, or digestive aid has it.
3. Choose DGL. Deglycyrrhizinated licorice (DGL) removes 99% of glycyrrhizin. It’s safe for digestion and won’t interfere with your meds.
4. Monitor your potassium. If you’ve consumed licorice, even once, get your potassium checked. Levels below 3.0 mmol/L are dangerous and can cause arrhythmias.
5. Don’t assume “natural” means safe. Licorice root is a powerful plant compound. It’s not harmless just because it’s herbal.

The American Heart Association recommends complete avoidance of glycyrrhizin-containing products for anyone on antihypertensive meds. The European Food Safety Authority says 100 mg/day is safe-but only for healthy people without high blood pressure or kidney issues. If you’re on meds, that limit doesn’t apply to you.

The Bigger Picture

The supplement industry is largely unregulated. In the U.S., manufacturers don’t have to list glycyrrhizin content. In the EU, products with more than 10 mg per serving must carry a warning. But here? You’re on your own.

That’s why it’s so easy to get caught off guard. A bottle labeled “natural adrenal support” might contain 150 mg of glycyrrhizin-enough to ruin your blood pressure control. And your doctor might not ask about herbal teas or candy.

Future regulations might change that. The FDA’s proposed Dietary Supplement Listing Act of 2023 could require full disclosure of active ingredients. But until then, you have to be the one watching out.

Don’t let a sweet taste cost you your health. If you’re managing blood pressure, licorice root isn’t a harmless indulgence. It’s a hidden risk. And it’s one you can easily avoid.