Licorice Root and Blood Pressure Medications: How It Kills Effectiveness

It’s easy to think of licorice root as just a sweet herbal remedy-something harmless you sip in tea or chew as a candy. But if you’re taking medication for high blood pressure, this common supplement could be quietly sabotaging your treatment. In fact, it’s not just a mild interference-it’s a full-on battle between nature and science, and your blood pressure is the battlefield.

What’s Really in Licorice Root?

Licorice root comes from the plant Glycyrrhiza glabra, grown mostly in Greece, Turkey, and parts of Asia. For thousands of years, it’s been used for coughs, stomach issues, and even as a sweetener. But the sweetness isn’t just sugar-it’s glycyrrhizin, a compound 50 times sweeter than table sugar. And this is where the trouble starts.

Glycyrrhizin doesn’t just taste sweet. It acts like a hormone mimic, tricking your body into thinking it’s getting more aldosterone, the hormone that tells your kidneys to hold onto salt and water. That sounds harmless, but when your body holds onto extra fluid, your blood pressure spikes. And if you’re already on medication to lower that pressure, this is like trying to drive uphill while someone hits the gas.

How It Neutralizes Your Blood Pressure Pills

The science is clear: glycyrrhizin blocks an enzyme called 11β-hydroxysteroid dehydrogenase type 2. Normally, this enzyme keeps cortisol (a stress hormone) from binding to mineralocorticoid receptors in your kidneys. When it’s blocked, cortisol acts like aldosterone. Result? Your kidneys keep sodium. You retain water. Blood volume goes up. Blood pressure rises.

This doesn’t just make your meds less effective-it can completely undo them. Studies show:

• For people on ACE inhibitors like lisinopril, licorice can reduce effectiveness by 30-50%.
• With ARBs like losartan, blood pressure control drops by about 25%.
• Even calcium channel blockers like amlodipine lose 15-20% of their power.
• The worst case? Spironolactone, a potassium-sparing diuretic. Licorice can cancel it out entirely within 7-10 days.

A 2015 study found some people saw their systolic blood pressure jump by as much as 30 mmHg after just two weeks of regular licorice use. That’s the difference between a controlled 130 and a dangerous 160.

It’s Not Just Candy

Most people think they’re safe if they avoid black licorice candy. But here’s the catch: 95% of licorice-flavored candies in the U.S. don’t even contain real licorice root. They use anise oil for flavor-no glycyrrhizin, no problem.

But if you’re buying herbal supplements, teas, or traditional remedies, you’re not so lucky. Products labeled "licorice root," "Glycyrrhiza glabra," or "licorice extract" almost always contain glycyrrhizin. And the amount? It varies wildly. One brand might have 5 mg per serving. Another might have 50 mg. No standardization. No warning labels in the U.S.

That’s why Dr. Johanna Salge Blake, a nutrition professor at Boston University, says: "People think they’re just having a sweet tea. Then they end up in the ER because their blood pressure went through the roof."

Real Cases, Real Consequences

It’s not theoretical. Real people are getting hurt:

• A 68-year-old man in the U.S. took licorice tea daily while on lisinopril. His BP climbed from 130/80 to 185/105 in 10 days.
• A Reddit user on r/HighBloodPressure noticed his systolic pressure jumped 22 points after eating "real licorice candy" while on amlodipine.
• In New Zealand, a 55-year-old man on fludrocortisone had his BP spike to 210/115, triggering panic attacks and hospitalization.

On PatientsLikeMe, 92% of 84 posts about licorice and blood pressure meds reported worsening control. Seventeen of those cases required emergency care.

And here’s the kicker: many people don’t even know they’re consuming it. A 2019 study from Australia found 6 out of 8 patients with licorice-induced hypertension had taken herbal supplements or Chinese medicine formulas that listed "licorice root"-and they had no idea it could affect their BP meds.

What About Potassium?

Another silent danger: licorice root drains potassium. It’s not just about fluid retention-it’s about electrolyte imbalance. Studies show regular use can drop serum potassium by 0.5 to 1.5 mmol/L. Normal range? 3.5-5.0. Once it dips below 3.0, you risk muscle weakness, irregular heartbeat, even cardiac arrest.

Doctors recommend checking potassium levels every two weeks if you’re on diuretics and consuming licorice. But the better advice? Don’t consume it at all.

What Can You Do?

If you’re on blood pressure medication, here’s what actually works:

1. Check every label. Look for "Glycyrrhiza glabra," "licorice root," or "licorice extract." Avoid anything with it.
2. Assume it’s there. If you’re unsure, skip it. Herbal teas, cough syrups, laxatives, and traditional remedies are common hidden sources.
3. Ask your pharmacist. Many don’t realize licorice is in 30% of herbal laxatives and 25% of Chinese medicine formulas.
4. Choose DGL. Deglycyrrhizinated licorice (DGL) has less than 1% glycyrrhizin. It’s safe for digestion and won’t interfere with your meds.
5. Stop all licorice for 2 weeks. Glycyrrhizin’s effects can linger for up to 14 days after you stop. Don’t assume quitting today fixes your BP tomorrow.

What’s Changing?

Regulation is slow, but moving. The European Union requires warning labels on products with more than 10 mg of glycyrrhizin per serving. The U.S. FDA has issued warnings but still doesn’t require labeling.

That’s why the proposed Dietary Supplement Listing Act of 2023 matters. If passed, it would force manufacturers to list exact glycyrrhizin amounts on labels. That’s a game-changer. Until then, you’re on your own.

And here’s the truth: the supplement industry makes $187 million a year selling licorice root. But your blood pressure isn’t a profit margin. It’s your life.

Bottom Line

You don’t need licorice root to feel better. There are safer herbs for digestion, coughs, and inflammation. And if you’re managing high blood pressure, every milligram of glycyrrhizin is a threat.

Don’t rely on labels alone. Don’t assume "natural" means safe. Don’t think "a little won’t hurt." The science says otherwise. One cup of licorice tea a day, for two weeks, can undo months of medication.

If you’re on blood pressure meds, the only safe choice is zero licorice root. Not "less." Not "occasional." Zero.