Licorice can raise blood pressure within about two weeks of daily consumption, and the effect is dose-dependent. In a controlled trial, healthy volunteers who ate licorice daily for just two weeks saw their systolic blood pressure climb by roughly 7 mmHg and diastolic by about 4 mmHg, with simultaneous increases in fluid volume. The speed and severity of the rise depend on how much you eat, how often, and your individual biology, but the timeline is surprisingly short for something most people think of as candy.
What the Two-Week Trial Actually Showed
The clearest evidence for how quickly licorice acts comes from a Finnish trial that gave healthy adults about 290 milligrams of glycyrrhizic acid per day for 14 days, roughly the amount in a modest daily portion of real licorice candy. After two weeks, both peripheral and central blood pressure rose significantly. Peripheral systolic pressure went up by about 7 mmHg and diastolic by about 4 mmHg, while central (aortic) systolic pressure climbed by about 8 mmHg. The participants also gained about half a liter of extra fluid volume, and measures of arterial stiffness worsened, meaning the heart had to work harder to push blood through the arteries.1PubMed Central. Daily Liquorice Consumption for Two Weeks Increases Augmentation Index and Central Systolic and Diastolic Blood Pressure
These were healthy people with normal blood pressure to start. The fact that measurable changes showed up so quickly, in people who weren’t already at risk, suggests that someone with borderline or elevated blood pressure could see a meaningful shift even sooner, or a larger one over the same timeframe. And two weeks was simply when the researchers measured; it’s possible the rise began earlier and was already building during the first week. Nobody has published a day-by-day timeline with daily blood pressure measurements after licorice initiation, so we don’t have a precise “day one” answer, but the best available evidence puts the window for noticeable change somewhere in the first one to two weeks.
Why Licorice Has This Effect
The active compound is glycyrrhizic acid, which your gut bacteria and liver convert into a molecule called glycyrrhetinic acid. That molecule blocks an enzyme in your kidneys that normally deactivates cortisol before it can latch onto receptors meant for aldosterone, the hormone that tells your kidneys to hang on to sodium and dump potassium.2PubMed. Licorice inhibits 11 beta-hydroxysteroid dehydrogenase messenger ribonucleic acid levels and potentiates glucocorticoid hormone action When the enzyme is blocked, cortisol floods those receptors and mimics an excess of aldosterone. The result is that your body retains sodium and water while losing potassium, a combination that drives blood pressure up.3Cardiovascular Research. The role of 11β-hydroxysteroid dehydrogenase in the pathogenesis of hypertension
This is why the condition is sometimes called pseudoaldosteronism: your body behaves as though aldosterone levels are sky-high, but if you test actual aldosterone, it’s often low. The distinction matters clinically because it means standard treatments that block aldosterone production won’t help; instead, the fix is to stop the licorice.4PubMed. Licorice-induced hypertension and syndromes of apparent mineralocorticoid excess
How Much Is Enough to Cause Problems
A systematic review and meta-analysis that pooled data from trials using at least 100 milligrams of glycyrrhizic acid per day found a consistent blood pressure rise: on average about 5.5 mmHg systolic and about 3 mmHg diastolic. The review also found a strong dose-response relationship, meaning the more glycyrrhizic acid people consumed daily, the higher their blood pressure went.5Journal of Human Hypertension. The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis
To translate that into food: 100 milligrams of glycyrrhizic acid can be found in as little as about 10 to 50 grams of licorice candy, depending on the brand and concentration. Some European licorice products, particularly Dutch and Scandinavian varieties, are quite concentrated. A person snacking on a bag throughout the day can easily hit or exceed 100 milligrams. It doesn’t take a dramatic binge. The meta-analysis noted that even what would be considered modest daily intake was enough to push blood pressure and potassium in the wrong direction.
There is no universally agreed-upon “safe” daily limit. The European Commission’s Scientific Committee on Food has previously suggested that 100 milligrams of glycyrrhizic acid per day is the upper boundary for most adults, but individual sensitivity varies widely enough that some people develop symptoms well below that threshold. The FDA classifies licorice-containing products as food supplements without strict dose limits on packaging, which contributes to people underestimating the risk.6PubMed Central. Licorice abuse: time to send a warning message
Who Is More Vulnerable
Not everyone reacts to the same dose of licorice the same way. Sensitivity to glycyrrhizic acid increases with age, is more common in women, and is amplified by pre-existing high blood pressure or conditions that slow digestion (since a longer gut transit time means more of the compound gets absorbed).7Therapeutic Advances in Endocrinology and Metabolism. Liquorice – All sorts of side effects and interactions If you already take medications for blood pressure or heart failure, licorice can undermine those drugs by working against them at the kidney level, creating a frustrating picture of “resistant hypertension” that doesn’t respond to the usual treatments.8PubMed Central. Bioactive Candy: Effects of Licorice on the Cardiovascular System
Genetics play a role, too. A study of people who developed hypertension from licorice found that about 20 percent of them carried variants in genes that control sodium channels in the kidneys, compared with under 4 percent in the general population. Those variants make the kidney more efficient at reabsorbing sodium, so when licorice tips the balance even further, blood pressure climbs faster and higher.9PubMed. Licorice-induced hypertension and common variants of genes regulating renal sodium reabsorption In rarer cases, people carry mutations in the gene for the very enzyme that licorice blocks. For those individuals, even small amounts of licorice can trigger a full-blown syndrome of high blood pressure and dangerously low potassium, because they already have reduced enzyme activity to begin with.10PubMed Central. Herbal Medicine Containing Licorice May Be Contraindicated for a Patient with an HSD11B2 Mutation
The Potassium Problem
Blood pressure gets most of the attention, but falling potassium is often the more immediately dangerous consequence. Because the mechanism pushes your kidneys to excrete potassium while retaining sodium, people who consume licorice chronically can develop significant hypokalemia. Potassium is essential for normal muscle and nerve function, including the electrical signaling that keeps your heart beating in rhythm.
Case reports illustrate how serious this can get. One patient arrived at the hospital with muscle weakness so severe she couldn’t move her limbs, traced back to chronic licorice consumption that had driven her potassium dangerously low.11PubMed. An unusual cause of hypokalemic paralysis: chronic licorice ingestion In a more extreme case, a woman developed a hypertensive crisis with blood pressure reaching 239/114 mmHg and acute fluid buildup in her lungs, requiring emergency treatment.12PubMed Central. A life-threatening case of pseudo-aldosteronism secondary to excessive liquorice ingestion These are the far end of the spectrum, but they demonstrate that the same mechanism responsible for a modest blood pressure increase can, with enough licorice and enough time, escalate into a medical emergency.
How Long the Effect Lasts After You Stop
One reason licorice catches people off guard is that the effects don’t vanish the moment you stop eating it. The enzyme inhibition is reversible, but recovery can take anywhere from days to several weeks, depending on how much licorice was consumed and individual factors.13PubMed Central. A hypokalemic muscular weakness after licorice ingestion: a case report In one documented case, a patient’s potassium wasting and elevated blood pressure persisted for two weeks after completely stopping licorice, even with potassium supplements and medication.11PubMed. An unusual cause of hypokalemic paralysis: chronic licorice ingestion
This lingering effect makes sense pharmacologically. Glycyrrhetinic acid, the active metabolite, has a long half-life in the body and accumulates with repeated dosing. Researchers measuring serum levels in people who consume licorice regularly have found widely varying concentrations, from barely detectable to quite high, which partly explains the range of recovery times.14PubMed. Identification of glycyrrhizin metabolites in humans and of a potential biomarker of liquorice-induced pseudoaldosteronism: a multi-centre cross-sectional study The practical takeaway: if you’ve been eating licorice daily and your blood pressure or potassium is off, you may need to wait a few weeks after quitting before labs and blood pressure readings return to baseline.
Hidden Sources You Might Not Expect
When clinicians talk about licorice and blood pressure, they don’t just mean black licorice candy. Glycyrrhizic acid shows up in a surprising range of products. One published case described a patient whose unexplained hypertension and low potassium were finally traced to licorice root extract hidden in herbal teas and sugar-free chewing gum she consumed in large quantities every day.15AACE Clinical Case Reports. The Hidden Liquorice: Apparent Mineralocorticoid Excess Caused by Inadvertent Exposure to Liquorice Root Extract Neither product had “licorice” prominently featured in its marketing, but both contained the root extract as a flavoring or sweetening agent.
Other common hiding spots include certain throat lozenges, herbal supplements (particularly those used in traditional medicine systems), some tobacco products, and various European confections that don’t obviously look like licorice candy. “Deglycyrrhizinated licorice” (DGL) is a processed form that has had most of the glycyrrhizic acid removed, specifically to avoid these cardiovascular effects. If you see DGL on a supplement label, it’s generally considered safe from a blood pressure standpoint. But regular licorice root extract, licorice powder, or products listing glycyrrhizin as an ingredient carry the full risk.
It’s worth noting that most “licorice-flavored” candy sold in the United States, particularly the red varieties, is flavored with anise rather than actual licorice root. Those products don’t carry the same blood pressure risk. The distinction matters: actual licorice root extract is what causes the enzyme inhibition. If the ingredient list doesn’t include glycyrrhiza, licorice root, or glycyrrhizin, the anise-flavored product is not the concern here.
Licorice During Pregnancy
The same enzyme that licorice blocks in your kidneys also exists in the placenta, where it serves as a barrier preventing the mother’s cortisol from reaching the fetus. When pregnant women consume high amounts of licorice, that barrier is weakened, and the developing baby is exposed to more cortisol than normal. A Finnish study following children born to mothers who ate heavy licorice during pregnancy (500 milligrams or more of glycyrrhizin per week) found that the girls were taller, heavier, and showed more advanced pubertal development, while both boys and girls scored roughly 7 points lower on IQ tests, had poorer memory, and were more than three times as likely to show attention and behavioral problems compared to children whose mothers ate little or no licorice.16American Journal of Epidemiology. Maternal Licorice Consumption During Pregnancy and Pubertal, Cognitive, and Psychiatric Outcomes in Children
An earlier study by a similar research group in the same Finnish cohort, examining the children at around age eight, had already found decrements in verbal and visuospatial abilities and increased externalizing behaviors like aggression and rule-breaking in the high-exposure group.17American Journal of Epidemiology. Maternal Licorice Consumption and Detrimental Cognitive and Psychiatric Outcomes in Children These are observational studies, so they can’t prove licorice caused the outcomes, but the biological mechanism is plausible and the dose-response pattern across both studies is consistent enough that many national health authorities now recommend pregnant women avoid licorice products entirely.
When Licorice Intake Mimics a Medical Condition
One of the underappreciated hazards of licorice is diagnostic confusion. A patient presenting with resistant hypertension, low potassium, and low aldosterone can look, on paper, like they have a rare adrenal disorder. Clinicians who don’t ask about dietary habits, including herbal teas and supplements, may order expensive hormone panels and imaging studies searching for an adrenal tumor or a genetic enzyme deficiency. In one published case, a patient with long-standing unexplained hypokalemia and uncontrolled hypertension was worked up extensively before the real cause, excessive licorice ingestion, was uncovered.18PubMed Central. Pseudohyperaldosteronism, liquorice, and hypertension
The distinguishing clue is that aldosterone levels are actually suppressed rather than elevated, because the body recognizes the sodium retention and tries to compensate by dialing down its own aldosterone production. But this finding alone doesn’t immediately point to licorice unless someone thinks to ask. If you’re dealing with unexplained hypertension or low potassium, mentioning all dietary supplements, herbal products, and candy habits to your doctor is genuinely helpful, not just a formality.
Interactions With Common Medications
Licorice doesn’t just raise blood pressure on its own; it can interact with several drug categories in ways that make existing treatments less effective or side effects worse. Diuretics that cause potassium loss, such as hydrochlorothiazide or furosemide, become more dangerous alongside licorice because both push potassium down. The combination can drop potassium to levels that trigger heart rhythm abnormalities. Similarly, people on digoxin for heart failure face increased toxicity when potassium falls, making licorice consumption a genuine safety concern.8PubMed Central. Bioactive Candy: Effects of Licorice on the Cardiovascular System
Corticosteroid medications already mimic some of the same effects licorice produces, and combining them can amplify fluid retention and electrolyte imbalance. For people taking blood pressure medications of any class, regular licorice consumption can create a puzzling picture where the drugs seem to stop working. The patient gets dose increases, additional drugs, and specialist referrals, when the real solution is stopping the licorice. Given how rarely dietary history is taken in detail during rushed clinical visits, this scenario plays out more often than the medical literature probably captures.