Licorice and Blood Pressure Medication Interactions: What You Need to Know

Have you ever reached for a piece of black licorice candy when you’re stressed? Or sipped on licorice tea thinking it’s just a soothing herbal drink? If you’re taking medication for high blood pressure, that habit could be quietly undoing your treatment - and putting your heart at risk.

How Licorice Tricks Your Body

Licorice root isn’t just a flavor. The real troublemaker is a compound called glycyrrhizin. When you eat or drink it, your body breaks glycyrrhizin down into glycyrrhetic acid. This metabolite shuts down an enzyme in your kidneys called 11β-HSD2. That enzyme normally protects your body from cortisol - a stress hormone that acts like aldosterone, a hormone that makes your kidneys hold onto salt and water while flushing out potassium.

When 11β-HSD2 is blocked, cortisol takes over. Your kidneys start behaving as if they’re flooded with aldosterone. Result? You retain extra fluid. Your blood volume goes up. Your blood pressure rises. At the same time, you lose potassium - sometimes dangerously low levels.

This isn’t a myth. It’s a well-documented physiological effect that’s been studied since the 1950s. And it doesn’t take much to trigger it. Consuming more than 100 milligrams of glycyrrhizin per day - roughly the amount in 60 to 70 grams of black licorice candy - can cause measurable changes in blood pressure and potassium levels within just two to four weeks.

Why This Matters for Blood Pressure Meds

If you’re on medication to lower your blood pressure, your body is trying to get rid of excess fluid and relax your blood vessels. Licorice does the exact opposite. It adds fluid, tightens vessels, and lowers potassium - all things your meds are trying to fix.

This interaction hits every class of blood pressure medication - but some are more vulnerable than others.

• Diuretics like hydrochlorothiazide already make you lose potassium. Add licorice, and your potassium drops even lower - increasing your risk of muscle cramps, irregular heartbeat, and even heart failure.
• ACE inhibitors and ARBs work by relaxing blood vessels and reducing fluid. Licorice floods your system with fluid, making these drugs less effective. Your blood pressure might stay high even though you’re taking your pills every day.
• Potassium-sparing diuretics like spironolactone are meant to keep potassium up. But licorice forces potassium out anyway. It’s like turning on a faucet while trying to plug a leak.
• Digoxin (Lanoxin) is especially dangerous. Low potassium makes your heart more sensitive to digoxin. That can lead to toxic levels, causing nausea, confusion, and life-threatening arrhythmias. There are documented cases of older adults ending up in the hospital with heart failure after eating licorice while on digoxin.

What Counts as Too Much Licorice?

Not all licorice products are the same. Many modern candies labeled "licorice" are actually flavored with anise oil and contain zero glycyrrhizin. That’s fine. But traditional black licorice - especially the chewy kind - often contains real licorice root extract.

Here’s what 100 mg of glycyrrhizin looks like in real life:

• 60-70 grams of black licorice candy (about 2.1-2.5 ounces)
• 1-2 cups of licorice tea made from root
• One or two daily doses of licorice root supplements

The problem? Most people don’t know how much they’re consuming. A single piece of licorice candy might contain 5-10 mg of glycyrrhizin. Eat five a day, and you’re already halfway to the danger zone. Herbal supplements? They’re not regulated. One bottle might have 150 mg per capsule. Another might have none. Labels rarely say.

Who’s at Highest Risk?

Some people are more sensitive to glycyrrhizin than others. You’re at higher risk if:

• You’re over 60
• You’re female
• You already have high blood pressure
• You have heart disease or kidney problems
• You’re taking digoxin or diuretics

Studies show that older adults and women experience stronger blood pressure spikes and more severe potassium loss from the same dose of licorice. That’s why doctors see more cases in women over 50 who’ve been drinking licorice tea daily for years - thinking it’s "natural" and harmless.

Signs You Might Be Having a Reaction

If you’re taking blood pressure meds and start noticing any of these, consider licorice as a possible cause:

• Your blood pressure suddenly goes up, even though you’ve been consistent with your meds
• You feel unusually tired, weak, or have muscle cramps
• You notice swelling in your ankles or feet
• Your heart feels like it’s skipping beats or racing
• You’re urinating more than usual

These aren’t vague symptoms. They’re red flags. A simple blood test can show if your potassium is low (below 3.5 mmol/L) or if your cortisol-to-cortisone ratio is abnormal - a telltale sign of glycyrrhizin interference.

What Should You Do?

If you’re on blood pressure medication:

1. Stop eating black licorice candy. Read labels. If it says "licorice extract" or "Glycyrrhiza glabra," avoid it.
2. Check your teas and supplements. Many herbal laxatives, digestive teas, and "adaptogen" blends contain licorice root. Look for alternatives without it.
3. Talk to your doctor. Tell them if you’ve been consuming licorice - even occasionally. They may want to check your potassium and blood pressure more closely.
4. Don’t assume "natural" means safe. Herbal doesn’t mean harmless. Licorice is a potent bioactive compound with real drug interactions.

If you’re not on blood pressure meds but enjoy licorice, you’re probably fine - as long as you keep it under 100 mg of glycyrrhizin per day. But if you’re over 60 or have heart issues, it’s still safer to skip it.

The Bigger Picture

This isn’t just about candy. It’s about how we think about supplements and "natural" remedies. People assume that because something comes from a plant, it’s safe to mix with prescription drugs. But plants contain powerful chemicals - and licorice is one of the most clinically significant food-drug interactions in medicine.

The FDA doesn’t require manufacturers to list glycyrrhizin content on supplements. That means you’re flying blind. A bottle labeled "licorice root extract" could be a silent threat.

Doctors now routinely ask patients with uncontrolled high blood pressure: "Do you eat licorice?" If the answer is yes - even once a week - it’s often the missing piece in their treatment puzzle.

Alternatives to Licorice

If you miss the sweet, earthy flavor, try these safe swaps:

• Anise-flavored candy - tastes similar, no glycyrrhizin
• Roasted chicory root tea - rich, slightly sweet, no blood pressure effects
• Dandelion root tea - naturally sweet, supports liver and kidney function
• Stevia or monk fruit - zero-calorie sweeteners with no known drug interactions

Final Takeaway

Licorice isn’t just a flavor. It’s a hormone disruptor with real, measurable effects on your blood pressure and heart. If you’re taking medication to control hypertension, even small, regular amounts can sabotage your treatment - and put you at risk for serious complications.

Don’t wait for symptoms to appear. If you’re unsure whether your candy, tea, or supplement contains glycyrrhizin, assume it does - and choose something else. Your blood pressure and your heart will thank you.