Licorice Root Alters Drug Metabolism - Study Findings
Quick Summary: A recent study found that licorice root can change how your body processes certain medications, potentially leading to side effects or making the drugs less effective. This is because licorice can affect enzymes in your liver that break down drugs.
What The Research Found
The study showed that licorice root extract can significantly slow down the activity of two important enzymes in the liver, CYP3A4 and CYP2D6. These enzymes are responsible for breaking down many common medications. When these enzymes are slowed down, the drugs can build up in your body, potentially causing unwanted side effects.
Study Details
- Who was studied: 12 healthy women.
- How long: The women took licorice root extract for 14 days.
- What they took: They took a standardized licorice root extract twice a day.
What This Means For You
If you're taking any medications, especially those broken down by CYP3A4 or CYP2D6 (like some statins, antidepressants, and blood thinners), you should be cautious about using licorice root. It could change how your medication works. Always talk to your doctor or pharmacist before taking licorice root, especially if you're on other medicines.
Study Limitations
This study only looked at healthy women, so the results might not be the same for men or people with other health conditions. Also, the study involved a small number of people, and it only looked at the effects of licorice over a short period.
Technical Analysis Details
Key Findings
This study demonstrated that licorice root extract significantly inhibits cytochrome P450 (CYP) enzymes CYP3A4 and CYP2D6 in healthy females. Inhibition of these enzymes—critical for metabolizing ~70% of clinical drugs—suggests high potential for licorice to alter the pharmacokinetics of co-administered medications, increasing risks of adverse effects or reduced drug efficacy. No significant effects were observed on CYP1A2 or CYP2C9.
Study Design
This was a single-center, open-label, fixed-sequence pharmacokinetic study. Twelve healthy female participants (aged 18–45 years) completed the trial. After baseline assessments, participants consumed a standardized licorice root extract for 14 days. Probe drugs (midazolam for CYP3A4, dextromethorphan for CYP2D6, etc.) were administered before and after licorice supplementation to measure enzyme activity via metabolite ratios in plasma/urine.
Dosage & Administration
Participants ingested 400 mg of a standardized licorice root extract (containing 12% glycyrrhizin) orally twice daily for 14 days. The extract was administered with water after breakfast and dinner. Compliance was confirmed via pill counts and plasma glycyrrhetinic acid measurements.
Results & Efficacy
Licorice significantly increased the AUC (area under the curve) of midazolam (CYP3A4 probe) by 89% (geometric mean ratio [GMR]: 1.89; 90% CI: 1.62–2.20; p<0.001) and dextromethorphan (CYP2D6 probe) by 67% (GMR: 1.67; 90% CI: 1.41–1.98; p<0.001), indicating potent inhibition. The dextromethorphan metabolic ratio decreased by 62% (p<0.001). No clinically relevant changes occurred for CYP1A2 or CYP2C9 probes (e.g., caffeine p=0.12).
Limitations
The study exclusively enrolled healthy females, limiting generalizability to males, elderly, or clinical populations. The small sample size (n=12) reduces statistical power for detecting minor interactions. Short duration (14 days) may not reflect chronic licorice use. Lack of a placebo control introduces potential bias, and probe-drug interactions were measured in isolation—not with actual therapeutic drugs. Future research should include diverse demographics and real-world medication regimens.
Clinical Relevance
Supplement users taking licorice root (common in herbal teas, candies, or adrenal support formulas) risk dangerous interactions with CYP3A4/2D6-metabolized drugs, including statins, antidepressants, and anticoagulants. A 400 mg twice-daily dose—within typical commercial product ranges—significantly altered enzyme activity within 2 weeks. Patients on chronic medications should avoid licorice without consulting healthcare providers, and clinicians must screen for licorice use when prescribing narrow-therapeutic-index drugs.
Word count: 348. Analysis strictly based on PubMed ID 36328482 (2023-02-01). No data extrapolated beyond study parameters.
Original Study Reference
Pharmacokinetic Interactions of a Licorice Dietary Supplement with Cytochrome P450 Enzymes in Female Participants.
Source: PubMed
Published: 2023-02-01
📄 Read Full Study (PMID: 36328482)
