The question of whether licorice can aid in weight loss is common, stemming from its long history in traditional medicine and modern research into its plant compounds. The focus is on the root and extracts of the plant Glycyrrhiza glabra, not the confectionary product. This natural substance contains several bioactive molecules that interact with the body’s metabolic systems. Scientific investigation has begun to explore the mechanisms and outcomes of using these extracts for body weight management. This article examines the scientific evidence behind the claims of licorice’s effect on body composition.
How Licorice Compounds Influence Metabolism
Licorice root contains compounds that may interfere with the body’s fat storage and breakdown processes. The main components of interest include triterpenoids, such as glycyrrhizin, and flavonoids, such as glabridin and licochalcone A. These molecules exert their effects by interacting with key enzymes involved in lipid metabolism and hormone regulation.
One primary mechanism involves the triterpenoid glycyrrhizin, which is metabolized in the gut to glycyrrhetinic acid. This metabolite inhibits the enzyme 11β-hydroxysteroid dehydrogenase Type 1 (11β-HSD1), found abundantly in fat cells and the liver. By blocking 11β-HSD1, licorice may reduce the local conversion of inactive cortisone into active cortisol within adipose tissue. Lower levels of local cortisol in fat cells are theorized to promote fat breakdown and discourage new fat accumulation.
The flavonoid compounds found in licorice also demonstrate anti-obesity potential through different pathways. Specifically, glabridin has been shown in laboratory models to inhibit adipogenesis, the process by which new fat cells are created. This compound works by suppressing the expression of genes and transcription factors, like PPARγ and C/EBPα, which drive fat cell differentiation and maturation. These dual actions—reducing the local activity of a fat-promoting hormone and inhibiting the creation of new fat cells—provide the theoretical basis for licorice’s effect on body composition.
Scientific Findings on Weight Reduction
Several human studies have investigated the direct impact of licorice extracts on measurable weight loss outcomes. Findings consistently show a reduction in body fat rather than overall body weight. In one study, healthy subjects consumed 3.5 grams of licorice extract daily for two months, resulting in a reduction in body fat mass and percentage, even though their Body Mass Index (BMI) did not significantly change.
Another randomized, double-blind, and placebo-controlled trial focused on Licorice Flavonoid Oil (LFO) in overweight subjects. Participants who consumed 300 milligrams of LFO daily for 12 weeks showed a significant reduction in body fat mass. This reduction was the main factor contributing to the observed difference in body weight and BMI compared to the placebo group. Licorice extracts have also been noted in clinical trials targeting visceral fat, the metabolically active fat stored deep within the abdomen.
A study involving subjects with a BMI between 23 and 30 demonstrated that 12 weeks of licorice extract supplementation led to a significant decrease in the abdominal fat area, including both visceral and subcutaneous fat. In overweight or obese women with Polycystic Ovary Syndrome (PCOS), adding licorice extract to a low-calorie diet proved more effective at improving obesity indices, including body weight and total body fat, than the diet alone. Despite these promising results, the current research is limited by small sample sizes, short study durations, and the use of highly concentrated extracts rather than whole licorice root, which makes broad conclusions about long-term effectiveness difficult.
Safe Consumption and Potential Side Effects
While some licorice compounds may offer metabolic benefits, consuming licorice extract for weight management requires careful consideration due to the presence of glycyrrhizin. This compound is responsible for pseudoaldosteronism, a well-documented condition that mimics the effects of excess aldosterone in the body. This occurs because glycyrrhizin blocks the enzyme that normally deactivates cortisol in the kidneys.
The resulting imbalance can lead to significant side effects, including the retention of sodium and water, which causes elevated blood pressure (hypertension). It can also lead to a drop in blood potassium levels (hypokalemia), which may cause muscle weakness and abnormal heart rhythms. Due to these risks, regulatory bodies recommend limiting glycyrrhizin intake to less than 100 milligrams per day.
For individuals interested in the potential benefits without the risk of glycyrrhizin-related side effects, Deglycyrrhizinated Licorice (DGL) is available. DGL is processed to remove the majority of the glycyrrhizin, making it safer for consumption, though it is typically used for gastrointestinal issues. Licorice extract should be avoided by individuals with pre-existing heart conditions, high blood pressure, kidney disease, or those who are pregnant, as these conditions increase sensitivity to the adverse effects of glycyrrhizin.