Licorice genuinely raises blood pressure, and the effect is not subtle. A controlled trial found that just two weeks of daily licorice consumption pushed systolic blood pressure up by about 7 mmHg and diastolic by about 4 mmHg, while also increasing fluid volume in the body by roughly half a liter.1PLOS ONE. Daily Liquorice Consumption for Two Weeks Increases Augmentation Index and Central Systolic and Diastolic Blood Pressure This is not folklore or a fringe concern. The culprit is a specific compound in the licorice root, and its mechanism is well understood. But the story gets more interesting when you look at why some people are hit much harder than others.
What Licorice Does Inside Your Body
The active ingredient behind licorice’s blood-pressure effect is glycyrrhizic acid, which gets broken down in your gut into a more potent form called glycyrrhetinic acid. This metabolite interferes with an enzyme called 11-beta-hydroxysteroid dehydrogenase type 2, which normally converts cortisol into an inactive form called cortisone. When that enzyme is blocked, cortisol sticks around and starts activating receptors that are normally reserved for aldosterone, a hormone that tells your kidneys to hold onto sodium and flush out potassium.2PubMed. Licorice inhibits 11 beta-hydroxysteroid dehydrogenase messenger ribonucleic acid levels and potentiates glucocorticoid hormone action The result is that your body behaves as if it has far too much aldosterone, even though actual aldosterone levels drop.3Cardiovascular Research. The role of 11β-hydroxysteroid dehydrogenase in the pathogenesis of hypertension
What follows is a predictable cascade: your kidneys retain sodium, you retain water, your blood volume goes up, and your blood pressure climbs. At the same time, potassium gets dumped into your urine. This combination of rising blood pressure and falling potassium is so characteristic that doctors have a name for it: pseudoaldosteronism, meaning it mimics a condition where your body overproduces aldosterone, except the aldosterone is actually suppressed.
How Much Licorice It Takes
A systematic review and meta-analysis found a clear dose-response relationship between daily glycyrrhizic acid intake and blood pressure. Higher doses correlated with higher systolic and diastolic readings, and the effect showed up even at what the authors called modest doses.4Journal of Human Hypertension. The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis One safety assessment proposed an acceptable daily intake of roughly 0.015 to 0.229 mg of glycyrrhizic acid per kilogram of body weight, which for an average adult translates to a very small amount of actual licorice product.5PubMed. Risk and safety assessment on the consumption of Licorice root (Glycyrrhiza sp.), its extract and powder as a food ingredient, with emphasis on the pharmacology and toxicology of glycyrrhizin
The trouble is that glycyrrhizic acid content varies enormously between products. A Danish government inspection program that tested over 200 licorice-containing food samples between 2019 and 2022 found it in everything from pure licorice extract and soft candy to herbal teas and ice cream bars.6Food Control. Glycyrrhizinic acid in licorice products on the Danish market Concentrated products like pure licorice extract contain far more glycyrrhizic acid per gram than, say, a licorice-flavored tea. This makes it genuinely difficult for a consumer to gauge their own intake without knowing the specific product’s composition.
It also matters how long you keep eating it. The two-week trial that produced clear blood pressure increases used moderate daily amounts.7PLOS ONE. Daily Liquourice Consumption for Two Weeks Increases Augmentation Index and Central Systolic and Diastolic Blood Pressure But the most severe case reports involve people who consumed licorice products daily for months or years. One classic case described a man who ate two to three large licorice candy bars every day for six to seven years before developing full-blown pseudoaldosteronism with hypertension and dangerously low potassium.8JAMA. Licorice-Induced Pseudoaldosteronism: Hypertension, Hypokalemia, Aldosteronopenia, and Suppressed Plasma Renin Activity
What the Symptoms Look Like
Licorice toxicity tends to present with a recognizable triad: high blood pressure, low potassium, and a shift in blood chemistry called metabolic alkalosis. The high blood pressure might not come with obvious symptoms at first. Many people discover it only when they visit a doctor for something else, or when the potassium depletion gets bad enough to cause muscle weakness, cramping, or heart palpitations. In a case involving a 78-year-old man, the toxicity was caught only because doctors were investigating his stubbornly low potassium and new-onset high blood pressure. Lab work showed the classic profile: suppressed aldosterone and suppressed renin, which helped distinguish the condition from other causes of high blood pressure paired with low potassium.9PubMed Central. Licorice Toxicity Presenting As Refractory Hypokalemia and Hypertension in an Elderly Patient
When potassium drops far enough, the consequences get dangerous. Severe hypokalemia can destabilize the heart’s electrical rhythm. At least one published case report documented a lethal arrhythmia directly attributed to licorice-induced potassium depletion.10PubMed Central. Lethal Arrhythmia Induced by Licorice Another case involved a 68-year-old man with well-controlled hypertension who had been drinking one to two liters of licorice tea daily for several months. He arrived at the hospital in hypertensive emergency, with a blood pressure reading of 210/110 and potassium so low it had triggered acute heart failure, all despite taking blood pressure medication.11PubMed Central. Hypertensive emergency induced by licorice tea
The good news is that the effect is generally reversible. Once you stop consuming licorice, the enzyme gradually recovers, cortisol stops acting like aldosterone, and blood pressure and potassium levels return to normal. Recovery can take days to weeks depending on how severe the toxicity was and how long the person was consuming licorice.
Who Is Most Vulnerable
Not everyone reacts to licorice the same way, and certain groups face disproportionate risk. Sensitivity to glycyrrhizic acid is increased by older age, existing hypertension, slower digestive transit, and female sex.12Europe PMC. Licorice abuse: time to send a warning message If you already have high blood pressure, adding licorice-induced sodium retention on top of that makes things worse faster. The elderly man in the licorice-tea case is a good illustration: his blood pressure had been well controlled on two medications, but the licorice overwhelmed his treatment regimen entirely.11PubMed Central. Hypertensive emergency induced by licorice tea
People taking certain medications face particular danger. Diuretics, especially those that waste potassium like hydrochlorothiazide, can compound the potassium loss that licorice already causes. The two effects together can push potassium to critically low levels much faster than either would alone. Anyone on blood pressure medication, heart medication, or potassium-wasting diuretics should treat licorice products as something to actively avoid rather than merely limit.
Genetic Susceptibility
Beyond age, sex, and medication use, some people carry genetic mutations that make them especially vulnerable. The enzyme that licorice suppresses is encoded by a gene called HSD11B2. People who carry mutations in that gene already have a weakened version of the enzyme. For them, even small amounts of glycyrrhizic acid can tip the balance toward a full-blown pseudoaldosteronism state. A clinical analysis concluded that carrying an HSD11B2 mutation is a genetic risk factor for licorice-induced hypertension, and that herbal medicines containing licorice may be contraindicated for these individuals.13PubMed Central. Herbal Medicine Containing Licorice May Be Contraindicated for a Patient with an HSD11B2 Mutation Most people do not know whether they carry such a mutation, which makes it hard to identify high-risk individuals before they run into trouble.
Licorice During Pregnancy
Pregnancy adds another dimension to the licorice question, because glycyrrhizic acid can cross the placenta and affect the developing fetus. The same enzyme that licorice blocks in adults also exists in the placenta, where it normally shields the fetus from excessive exposure to the mother’s cortisol. A Finnish cohort study found that heavy glycyrrhizin exposure during pregnancy roughly doubled the risk of being born before 38 weeks of gestation, with an odds ratio of 2.5.14PubMed. Birth outcome in relation to licorice consumption during pregnancy
A follow-up study from the same cohort tracked the children into adolescence and found more troubling patterns. Girls whose mothers consumed high amounts of glycyrrhizin (500 mg per week or more) were taller, heavier, and showed signs of more advanced pubertal development. Both boys and girls in the high-exposure group scored about 7 points lower on intelligence tests, had poorer memory performance, and had over three times the odds of attention-related behavioral problems compared with children whose mothers consumed little to no glycyrrhizin.15PubMed. Maternal Licorice Consumption During Pregnancy and Pubertal, Cognitive, and Psychiatric Outcomes in Children These are observational findings, and the researchers used the cautious language appropriate to that study design. But taken together, they paint a picture that is hard to dismiss: heavy licorice intake during pregnancy appears to carry real developmental risks.
Hidden Sources You Might Not Expect
When most people think of licorice, they picture black candy. But glycyrrhizic acid shows up in a surprisingly wide range of products. Herbal teas are a major and often overlooked source. The patient who developed a hypertensive emergency was drinking licorice tea, not eating candy.11PubMed Central. Hypertensive emergency induced by licorice tea Many “throat coat” and digestive teas list licorice root as a key ingredient, and people tend to drink tea daily without thinking of it as a medication. A person sipping two or three cups of strong licorice tea every day can accumulate a meaningful dose of glycyrrhizic acid over time.
Licorice root is also a common ingredient in traditional herbal medicine formulations, particularly in Chinese and Japanese (kampo) medicine, where it appears in many multi-herb combinations. Because licorice is often one of several ingredients, patients and practitioners may not immediately connect it to blood pressure changes. Smokeless tobacco is yet another source that rarely gets mentioned. The licorice used as a flavoring agent in some smokeless tobacco products may contribute to sodium retention and poor blood pressure control in users.16Europe PMC. Does smokeless tobacco cause hypertension?
One important distinction: many products labeled as “licorice flavored” in the United States actually use anise oil to create the characteristic flavor and contain no real licorice root at all. Anise oil does not contain glycyrrhizic acid and does not carry the same blood pressure risk. If you are trying to avoid glycyrrhizic acid specifically, check the ingredient list for “licorice root,” “licorice extract,” or “glycyrrhiza” rather than relying on the flavor alone.
Why Some People React More Than Others
Even among people with no genetic mutations and no special risk factors, there is a surprising amount of individual variation in how strongly licorice affects blood pressure. Part of the explanation lies in your gut bacteria. Glycyrrhizic acid is not the compound that actually inhibits the enzyme. It first needs to be converted by intestinal bacteria into glycyrrhetinic acid, the active metabolite. In animal studies, when glycyrrhizin was given orally, the parent compound never appeared in the blood at all; only the bacterially produced metabolite showed up, and it lingered for about 20 hours.17PubMed. Bioavailability study of glycyrrhetic acid after oral administration of glycyrrhizin in rats; relevance to the intestinal bacterial hydrolysis Germ-free animals that lacked gut bacteria showed essentially no absorption of the active metabolite, confirming that intestinal microbes are doing the heavy lifting.
The specific bacteria responsible have been identified: species from the genera Bacteroides and Eubacterium handle the main conversion pathway, while Streptococcus LJ-22 handles a minor alternative route.18Biological and Pharmaceutical Bulletin. Biotransformation of Glycyrrhizin to 18β-Glycyrrhetinic Acid-3-O-β-D-glucuronide by Streptococcus LJ-22, a Human Intestinal Bacterium Research in rats has shown that the abundance of Lactobacillus and Bacteroides in the gut positively correlates with how much active metabolite reaches the bloodstream, while higher levels of Escherichia-Shigella correlate with lower absorption.19PubMed Central. The Effect of Gut Microbiome Perturbation on the Bioavailability of Glycyrrhizic Acid in Rats
Studies using a traditional Japanese herbal medicine containing glycyrrhizic acid found large individual differences in how much active metabolite people absorbed. The researchers found that differences in gut microbiota composition could largely explain this variation, and that multiple bacterial species worked together rather than any single species being responsible.20Biological and Pharmaceutical Bulletin. Impact of Gut Microbiota on the Pharmacokinetics of Glycyrrhizic Acid in Yokukansan, a Kampo Medicine This means that two people eating the same amount of licorice can end up with very different levels of the active compound in their blood. One person’s gut flora might efficiently convert most of the glycyrrhizic acid into its potent form, while another person’s might convert much less. There is currently no practical test to tell you which camp you fall into.
What Licorice Does to Your Arteries Beyond Simple Pressure
The blood pressure story has a layer that goes beyond just fluid retention. The same two-week trial that measured the blood pressure increase also found that licorice raised a measure called the augmentation index, which reflects how much pressure waves bounce back from the peripheral arteries toward the heart. In the licorice group, this index climbed from about 7% to 11%, and aortic pulse pressure went up by about 4 mmHg.7PLOS ONE. Daily Liquourice Consumption for Two Weeks Increases Augmentation Index and Central Systolic and Diastolic Blood Pressure In plain terms, licorice made the arteries stiffer and increased the workload on the heart beyond what the raw blood pressure numbers alone would suggest. This matters because central arterial stiffness is considered an independent risk factor for cardiovascular events. A person whose arm-cuff blood pressure rises modestly might actually be experiencing a more significant strain on their cardiovascular system than the numbers would imply.
The study also separated peripheral blood pressure from central blood pressure, the pressure your aorta and heart actually experience. Central systolic pressure rose by about 8 mmHg, slightly more than the peripheral measurement. This distinction is clinically meaningful because central pressure is a better predictor of organ damage than what a standard blood pressure cuff reads. Licorice, in other words, is not just a mild fluid-retention issue. It appears to alter vascular function in ways that amplify its cardiovascular impact.
The Anise Confusion and Other Misconceptions
One of the most common misconceptions is that all black licorice candy contains real licorice. In much of the world, particularly the United States, products labeled as licorice candy are often flavored with anise oil rather than licorice root extract. If the ingredient list does not mention glycyrrhiza or licorice extract, the product probably poses no blood pressure risk from glycyrrhizic acid. In Northern European countries, however, real licorice extract is standard in candy, and glycyrrhizic acid levels in these products can be substantial.
Another misconception is that deglycyrrhizinated licorice (DGL) carries the same risk. DGL is a processed form of licorice that has had most of the glycyrrhizic acid removed. It is commonly sold as a supplement for digestive complaints. Because the problematic compound has been stripped out, DGL does not cause the same blood pressure or potassium problems. If you enjoy the taste of licorice and want to avoid the cardiovascular risk, DGL supplements or anise-flavored products are the standard alternatives.
A subtler misconception is that licorice toxicity requires enormous amounts consumed over years. The evidence does not support that. The meta-analysis found blood pressure effects even at modest doses, and the controlled trial produced clear changes in just two weeks.4Journal of Human Hypertension. The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis The dramatic case reports involving years of heavy consumption grab attention, but they represent the extreme end of a spectrum that starts much closer to what many people would consider normal snacking or tea-drinking behavior. A person who habitually drinks a few cups of licorice root tea per day is not doing something obviously reckless, yet that level of intake is enough to move the needle on blood pressure and potassium, especially in someone already at risk.