Licorice Root Extract 4:1 (Glycyrrhiza glabra)
Mechanism of Action +
### Pharmacokinetics and Metabolism of Glycyrrhizin The primary active constituent of Glycyrrhiza glabra is glycyrrhizin (also known as glycyrrhizic acid), a triterpenoid saponin that typically comprises 7% to 10% of the root's dry weight. Upon oral ingestion, glycyrrhizin is poorly absorbed in its native form. Instead, it undergoes extensive hydrolysis by the intestinal microbiome, specifically by bacteria possessing beta-glucuronidase activity. This enzymatic cleavage removes the two molecules of glucuronic acid, yielding the aglycone, 18-beta-glycyrrhetinic acid (GE). GE is highly lipophilic and is rapidly absorbed across the intestinal epithelium into the portal circulation. Once in the liver, GE is metabolized by cytochrome P450 enzymes and undergoes phase II conjugation, primarily glucuronidation and sulfation, before being excreted into the bile. A significant portion of GE undergoes enterohepatic recirculation, which dramatically extends its half-life in the human body, often leading to cumulative physiological effects with chronic daily dosing.
### Inhibition of 11-Beta-Hydroxysteroid Dehydrogenase (11β-HSD) The most profound pharmacological mechanism of glycyrrhetinic acid is its competitive inhibition of the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2). In healthy human physiology, 11β-HSD2 is highly expressed in aldosterone-selective tissues, such as the distal convoluted tubules and collecting ducts of the kidneys, as well as the colon and salivary glands. Its primary role is to catalyze the conversion of active cortisol into its inactive metabolite, cortisone. Because the mineralocorticoid receptor (MR) has an equal affinity for both aldosterone and cortisol, and because circulating cortisol levels are orders of magnitude higher than aldosterone, 11β-HSD2 acts as a crucial 'gatekeeper' enzyme. It prevents cortisol from illicitly activating the MR.
When licorice extract is consumed, GE potently inhibits 11β-HSD2. This leads to a localized surge in intracellular cortisol within the renal tubules. The excess cortisol binds to and activates the mineralocorticoid receptor, mimicking the effects of hyperaldosteronism. This activation upregulates the epithelial sodium channel (ENaC) and the Na+/K+-ATPase pump on the basolateral membrane. The physiological result is aggressive sodium reabsorption, obligate water retention, and the simultaneous excretion of potassium and hydrogen ions. Clinically, this manifests as volume-expanded hypertension, hypokalemia, and metabolic alkalosis—a condition known as pseudohyperaldosteronism. This mechanism is the exact reason Examine.com grades Licorice with an 'F' for Blood Pressure, denoting a strong, reliable detriment (increase) in blood pressure across multiple human trials.
### Antioxidant and Anti-Atherogenic Pathways: Glabridin Beyond the triterpenoids, licorice root is rich in polyphenols and flavonoids, the most notable being glabridin, an isoflavan. Glabridin is highly lipophilic and readily incorporates into the lipid bilayer of low-density lipoprotein (LDL) particles. Once embedded, it acts as a potent chain-breaking antioxidant. It scavenges reactive oxygen species (ROS) and inhibits the oxidative modification of LDL by macrophages and endothelial cells. Oxidized LDL (ox-LDL) is a primary driver of atherogenesis, as it is taken up by macrophage scavenger receptors, leading to foam cell formation and the development of atherosclerotic plaques. Clinical data from Examine.com highlights a Grade C evidence tier for licorice's ability to moderately improve LDL oxidation, a benefit largely attributed to the glabridin content. Furthermore, glabridin has been shown to inhibit the activity of cytochrome P450 3A4 (CYP3A4) and CYP2B6 in vitro, which may have implications for drug-herb interactions.
### Gastrointestinal Mucosal Defense Licorice has been used historically for gastrointestinal complaints, specifically ulcers and gastritis. The mechanism here is multifaceted. Glycyrrhizin and its derivatives stimulate the proliferation of gastric mucosal cells and increase the secretion of mucin, enhancing the protective mucosal barrier against gastric acid and pepsin. Additionally, licorice extracts inhibit the enzymes 15-hydroxyprostaglandin dehydrogenase and delta-13-prostaglandin reductase. By inhibiting these enzymes, licorice increases the local tissue concentration of prostaglandins (specifically PGE2 and PGF2-alpha) in the stomach lining. Prostaglandins are critical for maintaining gastric mucosal integrity, promoting blood flow, and stimulating bicarbonate secretion. This mechanism is similar to the protective effects of synthetic prostaglandin analogs used in ulcer therapy, and it explains the traditional efficacy of licorice in treating peptic ulcer disease.
### Dermatological Mechanisms: Tyrosinase Inhibition In dermatological applications, licorice extracts are frequently utilized for their skin-lightening and anti-erythema properties. The flavonoid liquiritin and the isoflavan glabridin are the primary active agents. Glabridin is a potent inhibitor of tyrosinase, the rate-limiting enzyme in melanogenesis (the production of melanin). By inhibiting tyrosinase activity in melanocytes, glabridin reduces the synthesis of eumelanin and pheomelanin, effectively lightening hyperpigmented skin and ameliorating conditions like melasma. Concurrently, liquiritin does not inhibit tyrosinase but rather induces the dispersion of existing melanin, accelerating its removal from the epidermis. The anti-inflammatory properties of these flavonoids also make topical licorice effective for managing the erythema and pruritus associated with eczema and atopic dermatitis.
### Endocrine and Hormonal Modulation Licorice root also interacts with the broader endocrine system. Examine.com notes a Grade C evidence tier for a small increase in cortisol, directly related to the 11β-HSD inhibition discussed earlier. However, licorice also exhibits mild phytoestrogenic activity. Certain isoflavones in the root can bind to estrogen receptors (ER-alpha and ER-beta), acting as selective estrogen receptor modulators (SERMs). Depending on the endogenous estrogen environment, they may exert weak estrogenic or anti-estrogenic effects. Furthermore, high doses of glycyrrhizin have been shown to inhibit 17-hydroxysteroid dehydrogenase and 17-20 lyase, enzymes involved in the biosynthesis of testosterone. While Examine.com notes 'No effect' on Luteinizing Hormone (Grade D) and Estrogen (Grade D) in specific small trials, the potential for licorice to lower serum testosterone in males has been documented in other literature, making it a compound of interest (and caution) for endocrine modulation.
Does licorice root interact with any medications? +
What not to mix with licorice extract? +
Who should not take licorice root extract? +
Is licorice root bad for the heart? +
How much licorice root is safe per day? +
What are the benefits of licorice root for women? +
How is licorice root used for skin whitening? +
How long does licorice stay in your system? +
What are the side effects of licorice on the skin? +
What does a 4:1 extract mean? +
What is DGL (Deglycyrrhizinated Licorice)? +
Can licorice root help with heartburn? +
Does licorice root increase cortisol? +
Can I take licorice root while pregnant? +
Does licorice root cause low potassium? +
How does licorice root affect testosterone? +
Is licorice root good for ulcers? +
Can licorice root help with eczema? +
Everything About Licorice Root Extract 4:1 (Glycyrrhiza glabra) Article
## Introduction to Licorice Root Extract Licorice root (*Glycyrrhiza glabra*) is one of the oldest and most widely utilized botanicals in human history. The name *Glycyrrhiza* is derived from the Greek words for "sweet root," a nod to its primary active compound, glycyrrhizin, which is estimated to be 50 times sweeter than sucrose. Historically, its therapeutic use dates back to the Roman Empire, where Pliny the Elder recommended it as an expectorant. It also serves as a foundational herb in Traditional Chinese Medicine (TCM), known as *Gan Cao*, where it is often used to harmonize other herbal ingredients in complex formulas.
Today, Licorice Root Extract is available in various concentrations, such as a 4:1 extract, meaning four parts of the raw root are concentrated into one part of the extract. While it is famous as a flavoring agent in candies and tobacco, its clinical applications in sports nutrition, gastroenterology, and endocrinology are profound. However, licorice is a double-edged sword: it possesses incredible healing properties for the gut and cardiovascular system, but its standard form carries significant risks for blood pressure and potassium balance.
## The Biochemistry of Glycyrrhiza glabra To understand licorice, you must understand its two primary classes of active compounds: triterpenoid saponins and flavonoids.
**Glycyrrhizin and Glycyrrhetinic Acid:** The root contains 7% to 10% glycyrrhizin. When you consume licorice extract, your gut bacteria cleave glycyrrhizin into its active aglycone, glycyrrhetinic acid. This compound is a potent inhibitor of an enzyme called 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme normally lives in your kidneys and converts active cortisol into inactive cortisone. By blocking this enzyme, licorice causes a localized surge of cortisol in the kidneys. This excess cortisol binds to mineralocorticoid receptors, tricking the body into thinking it has high levels of aldosterone. The result? Your body aggressively holds onto sodium and water while flushing out potassium.
**Glabridin and Liquiritin:** On the other side of the biochemical spectrum are the flavonoids. Glabridin is a powerful antioxidant isoflavan. It is highly lipophilic, meaning it loves fat. It embeds itself into your LDL cholesterol particles and acts as a shield, preventing reactive oxygen species from oxidizing the LDL. This is crucial because oxidized LDL is the primary driver of arterial plaque buildup. Liquiritin, another flavonoid, gives the root its yellow color and is highly prized in dermatology for its ability to disperse melanin and brighten the skin.
## Gut Health and Gastric Support The most common and clinically supported use for licorice root is the treatment of gastrointestinal complaints, specifically dyspepsia, gastritis, and peptic ulcers. Licorice does not merely neutralize stomach acid like an over-the-counter antacid; it actively heals the mucosal barrier.
It achieves this by inhibiting enzymes that break down prostaglandins in the stomach. Prostaglandins are lipid compounds that promote blood flow to the stomach lining and stimulate the secretion of protective mucus and bicarbonate. By keeping local prostaglandin levels high, licorice extract helps the stomach build a thick, robust shield against its own acid and pepsin. For this purpose, doses ranging from 760mg to 15g of the whole root (or equivalent extract) have been used historically.
## Cardiovascular Impacts: The Good and the Bad Licorice presents a fascinating paradox for cardiovascular health, clearly reflected in the Examine.com evidence database.
**The Good: Reducing LDL Oxidation (Grade C)** Examine.com highlights a Grade C evidence tier for licorice's ability to moderately improve LDL oxidation. In clinical trials, participants consuming licorice extract showed a significant reduction in the susceptibility of their LDL cholesterol to oxidative stress. This anti-atherogenic effect is largely attributed to the glabridin content, which scavenges free radicals before they can damage the lipid particles.
**The Bad: Blood Pressure Detriment (Grade F)** Conversely, Examine.com assigns licorice a Grade F for blood pressure, indicating a strong, reliable negative effect. Across 5 studies involving 137 participants, standard licorice consumption caused a moderate to severe increase in blood pressure. This is the direct result of the glycyrrhetinic acid-induced sodium and water retention discussed earlier. Chronic consumption of standard licorice extract can lead to a condition known as pseudohyperaldosteronism, characterized by dangerous hypertension and hypokalemia (low potassium).
## Cortisol and the Endocrine System Because licorice inhibits the breakdown of cortisol, it effectively extends the half-life of this stress hormone in the body. Examine.com notes a Grade C evidence tier for a small increase in circulating cortisol following licorice ingestion.
In the realm of alternative medicine, this mechanism is sometimes leveraged to treat "adrenal fatigue" or chronic exhaustion, providing the body with a prolonged cortisol curve to maintain energy and blood pressure. However, this must be managed carefully. Furthermore, licorice exhibits mild phytoestrogenic activity and has been shown in some literature to potentially lower testosterone levels by inhibiting the enzymes responsible for its synthesis (17-hydroxysteroid dehydrogenase).
## DGL vs. Standard Extract: What You Need to Know Because of the severe blood pressure risks associated with glycyrrhizin, the supplement industry developed Deglycyrrhizinated Licorice (DGL).
DGL is licorice root extract that has been processed to remove the glycyrrhizin, typically leaving less than 1% remaining. By removing this compound, DGL eliminates the risk of 11β-HSD2 inhibition, meaning it will not cause sodium retention, potassium loss, or hypertension.
Crucially, DGL retains all the beneficial flavonoids (glabridin, liquiritin) and polysaccharides. Therefore, if you are using licorice for gut health, heartburn, or antioxidant support, DGL is the vastly superior and safer choice for long-term use. Standard extracts (like a 4:1 whole root extract) should only be used short-term under medical supervision, typically for acute respiratory or specific endocrine applications.
## Synergies and Stacking Licorice extract is rarely used in isolation in traditional medicine. Modern research supports several synergistic combinations: * **Licorice + Lycopene:** Examine.com notes that combining licorice with lycopene (the red pigment in tomatoes) works synergistically to prevent LDL oxidation, offering compounded cardiovascular protection. * **Licorice + Panax Ginseng:** A classic adaptogenic stack. Combined with Oriental bezoar, this trio is thought to reduce stress-induced biomarker changes, harmonizing the HPA axis. * **Licorice + Cranberry:** This combination confers synergistic anti-inflammatory and antibacterial effects, particularly useful for protecting the gut and urinary tract microbiomes.
## Safety, Side Effects, and Contraindications The safety profile of standard licorice extract is highly dose- and duration-dependent. The acceptable daily intake (ADI) for glycyrrhizin is suggested to be 0.2 mg/kg/day. Exceeding this through high doses of standard extract can lead to severe adverse reactions.
**Contraindications include:** * **Pregnancy:** Drugs.com explicitly states that use during pregnancy should be avoided. Licorice has reputed abortifacient effects and has been linked to negative effects on the neuroendocrine function and cognitive behavior of children born to mothers who consumed high amounts. * **Hypertension and Heart Disease:** Due to its fluid-retaining properties, it is strictly contraindicated for anyone with high blood pressure or congestive heart failure. * **Hypokalemia:** It will exacerbate low potassium levels, potentially leading to lethal cardiac arrhythmias. * **Hormone-Sensitive Cancers:** Due to its estrogenic activity, individuals with a history of breast, ovarian, or uterine cancer, or endometriosis, should avoid it.
If you are scheduled for surgery, Drugs.com recommends stopping licorice at least two weeks prior to avoid complications with blood pressure and potassium levels during anesthesia.