Licorice Root and Blood Pressure Medications: Why It Kills Their Effectiveness

It’s not just sugar. If you’re taking blood pressure medication and you’ve been snacking on black licorice, sipping licorice tea, or popping herbal supplements labeled "licorice root," you might be quietly sabotaging your treatment. This isn’t a myth. It’s not a warning you can ignore. Licorice root doesn’t just slightly reduce your meds’ effectiveness-it can make them nearly useless, pushing your blood pressure into dangerous territory within days.

What’s Really in Licorice Root?

Licorice root comes from the plant Glycyrrhiza glabra. It’s been used for thousands of years-for coughs, stomach issues, even as a sweetener. But the sweetness? That’s not natural sugar. It’s glycyrrhizin, a compound about 50 times sweeter than table sugar. And while it tastes good, it acts like a hormone in your body that mimics aldosterone, the same hormone your kidneys use to hold onto salt and water. That’s the problem.

When you consume licorice root regularly, glycyrrhizin gets broken down into glycyrrhetic acid. This acid blocks an enzyme called 11β-hydroxysteroid dehydrogenase type 2. That enzyme normally keeps cortisol (a stress hormone) from binding to your mineralocorticoid receptors. When it’s blocked, cortisol acts like aldosterone. Result? Your body holds onto more sodium, loses potassium, and retains extra fluid. All of that = higher blood pressure.

It doesn’t take much. Studies show that consuming more than 100 mg of glycyrrhizin per day for two weeks can trigger these effects. That’s roughly 50 grams of real licorice candy-or a daily cup of licorice tea made from the root. Some supplements contain even higher concentrations. And the damage doesn’t vanish the moment you stop. Because glycyrrhizin sticks around, its effects can last up to two weeks after you quit.

How It Kills Blood Pressure Meds

If you’re on medication to lower your blood pressure, licorice root doesn’t just add stress to your system-it actively fights your drugs. Here’s how it messes with the most common classes:

• ACE inhibitors (like lisinopril): These drugs work by relaxing blood vessels and reducing fluid volume. Licorice does the opposite-it increases fluid volume. Studies show this combination can reduce the drug’s effectiveness by 30-50%.
• ARBs (like losartan): These block the hormone that narrows blood vessels. Licorice bypasses this by creating its own sodium-retaining effect. Research shows a 25% drop in effectiveness.
• Calcium channel blockers (like amlodipine): These relax artery walls. Licorice increases blood volume and stiffens vessels. One study found blood pressure control worsened by 15-20% in patients taking both.
• Potassium-sparing diuretics (like spironolactone): This is the worst combo. These drugs keep potassium in your body. Licorice drains potassium. One case report showed complete loss of therapeutic effect within 7-10 days. Patients ended up in the ER with dangerously low potassium and sky-high blood pressure.

The numbers don’t lie. In hypertensive patients, licorice can raise systolic blood pressure by 10-30 mmHg. That’s the difference between controlled and crisis levels. One man on lisinopril saw his BP jump from 130/80 to 185/105 in just 10 days after starting licorice tea. Another, on amlodipine, saw a 22-point systolic spike over two weeks. These aren’t rare cases-they’re documented in medical journals and patient forums.

It’s Not Just Candy

Most people think they’re safe if they avoid black licorice candy. But here’s the trap: 95% of licorice-flavored candies in the U.S. don’t contain real licorice root. They use anise oil, which tastes similar but has zero glycyrrhizin. So if you’re avoiding candy, you might think you’re safe.

But real licorice root hides in plain sight:

• Herbal teas labeled "licorice root" or "Glycyrrhiza glabra"
• Dietary supplements for digestion, immunity, or stress
• Traditional Chinese medicine formulas (25% contain licorice root)
• Some cough syrups and throat lozenges
• Even certain herbal laxatives (30% contain it)

Check the ingredient list. If it says "licorice root," "Glycyrrhiza glabra," or "licorice extract," you’re getting glycyrrhizin. If it says "anise oil," "fennel," or "natural flavor," you’re likely safe. But don’t assume. Labels aren’t always clear. A 2021 study found only 37% of licorice supplements warn about blood pressure risks.

Who’s at Risk?

Anyone on blood pressure medication is at risk. But some people are more vulnerable:

• Those on potassium-sparing diuretics (spironolactone, eplerenone)
• People with kidney disease or heart failure
• Older adults, whose bodies clear glycyrrhizin slower
• Those already struggling to control their BP

Low potassium is a silent red flag. Normal levels are 3.5-5.0 mmol/L. Licorice can drop them below 3.0 mmol/L in under 10 days. Symptoms? Muscle cramps, weakness, irregular heartbeat, fatigue. These are often mistaken for aging or stress. But they’re warning signs your meds are failing.

What Should You Do?

If you’re on blood pressure medication:

1. Stop all licorice root products. That includes tea, candy, supplements, and herbal remedies. Even small daily amounts add up.
2. Check every label. Look for "Glycyrrhiza glabra" or "licorice root." Avoid anything with it.
3. Ask your pharmacist. They can scan your supplements and OTC products for hidden licorice. Many don’t even know it’s in them.
4. Get your potassium checked. If you’ve been consuming licorice, ask for a blood test. Levels below 3.5 mmol/L need immediate attention.
5. Switch to DGL if you need digestive support. Deglycyrrhizinated licorice (DGL) has over 99% of the glycyrrhizin removed. It’s safe for your BP meds and still helps with heartburn or ulcers.

The American Heart Association says people on antihypertensives should avoid licorice root entirely. The European Food Safety Authority sets a "safe" limit of 100 mg glycyrrhizin per day-but that’s for healthy people. If you’re on meds, there’s no safe dose.

What About the Future?

Right now, the FDA doesn’t require supplement makers to list glycyrrhizin amounts. That’s changing. The proposed Dietary Supplement Listing Act of 2023 would force manufacturers to disclose active ingredients. That’s good news. But until then, you’re on your own.

Some companies are catching on. More DGL products are appearing on shelves. But if you’re buying licorice root for "natural healing," you’re risking your health. The data is clear: the benefits don’t outweigh the dangers when you’re on blood pressure meds.

There’s no magic workaround. No "just a little" rule. No exception for "organic" or "wildcrafted." Glycyrrhizin is glycyrrhizin. And it doesn’t care how pure your intentions are.

If you’ve been using licorice root and your blood pressure has been stubborn, it’s not your fault. It’s not your meds failing. It’s likely something you thought was harmless.

Stop it. Check your labels. Talk to your doctor. Your blood pressure-and your heart-will thank you.

What to Do Next

If you’re on blood pressure medication:

• Review every supplement, tea, and OTC product in your cabinet.
• Call your pharmacist and ask them to scan your bottles for licorice root.
• Get a simple blood test for potassium-this takes five minutes and could save your life.
• If you’ve been using licorice, don’t just quit-tell your doctor. They may need to adjust your meds or monitor you more closely.

There’s no shortcut. No "natural" workaround that’s safer. Licorice root isn’t evil-it’s powerful. And when you’re on medication, power without control is dangerous. Protect your health. Skip the root. Your heart will thank you.