Licorice root dosage and safety
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Licorice Root Dosage: Safe Levels and Toxicity Risks
Safe Dosage Ranges in Animal and Human Studies
Animal studies show that high doses of licorice root extract (up to 2,000 mg/kg as a single dose and up to 1,000 mg/kg daily for 120 days) did not cause toxicity or death in mice, with no significant changes in blood pressure, blood tests, or organ health observed . In humans, daily doses of licorice root extract containing up to 217 mg of glycyrrhizin for four weeks were generally well tolerated, with no significant side effects in most healthy volunteers. However, higher doses (380 mg and 814 mg glycyrrhizin per day) led to side effects such as headache, high blood pressure, low potassium, and fluid retention, especially in individuals with underlying health risks or those taking oral contraceptives .
Safety Profile and Side Effects
Licorice root is generally considered safe at low to moderate doses for short-term use. However, chronic or high-dose intake can cause serious side effects, mainly due to glycyrrhizin, the main active compound. These side effects include pseudoaldosteronism (a condition mimicking excess mineralocorticoid hormones), hypokalemia (low potassium), and hypertension (high blood pressure) 68. The risk of these side effects increases with higher doses, longer duration of use, older age, constipation, low blood protein, liver dysfunction, and use of certain medications like diuretics .
Special Considerations for Dosage and Toxicity
The relationship between licorice dosage, toxicity, and efficacy can be complex, especially when combined with other herbs. For example, in animal studies, increasing the dose of licorice in combination with kansui (another traditional herb) increased toxicity and reduced efficacy, with a critical threshold between a 2:1 and 1:1 ratio of kansui to licorice . This highlights the importance of careful dosing and awareness of potential interactions.
Safety Assessments in Extracts and Supplements
Licorice root extracts from different sources have shown good safety profiles in laboratory tests, with no evidence of toxicity or irritability in animal models and no detectable heavy metals . In clinical trials, supplementation with 1,000 mg/day of licorice root extract for 12 weeks in women with nonalcoholic fatty liver disease was well tolerated and led to improvements in liver health and metabolic markers, with no major adverse effects reported .
Hepatoprotective and Detoxifying Effects
Licorice root extract has demonstrated protective effects against liver damage and toxicity from certain drugs and pesticides in animal studies, further supporting its safety at moderate doses 45. However, these benefits do not eliminate the risk of side effects at higher doses or with prolonged use.
Conclusion
Licorice root is generally safe at low to moderate doses for short-term use, with most studies supporting daily intakes of up to 200 mg glycyrrhizin or 1,000 mg extract as safe for most healthy adults 12610. Higher doses or long-term use increase the risk of serious side effects, especially in sensitive individuals or those with underlying health conditions 268. Monitoring for symptoms like high blood pressure and low potassium is important, and licorice should be used cautiously in combination with other herbs or medications. Always consult a healthcare provider before starting licorice supplements, especially for prolonged use or higher doses.
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