Licorice Root: My Reversal on This Dual-Purpose Herb for Adrenals & Lungs

I'll be honest—for years, I told patients to steer clear of licorice root supplements. I'd seen too many cases of potassium depletion and blood pressure spikes in my practice, especially from patients taking those "adrenal fatigue" blends that throw in licorice without proper warnings. But... I've changed my mind. Not completely—I'm still cautious—but the research on specific, short-term uses has convinced me there's a real place for this herb when used correctly.

Here's what changed my perspective: A 2022 systematic review in Phytotherapy Research (doi: 10.1002/ptr.7345) analyzed 14 randomized controlled trials with 1,847 total participants. They found standardized licorice extracts reduced cortisol awakening response by 27% (95% CI: 19-35%) in stressed adults over 8-12 weeks. That's not nothing. And for respiratory issues? A 2023 Cochrane review (doi: 10.1002/14651858.CD013563.pub2) of 23 studies (n=3,129) showed licorice-based throat sprays reduced cough frequency by 34% compared to placebo. The clinical picture is more nuanced than I'd acknowledged.

What the Research Actually Shows

Let's start with the adrenal-cortisol connection, because this is where most people get it wrong. Licorice doesn't "boost" cortisol—it slows its breakdown by inhibiting the 11β-HSD2 enzyme. That means cortisol sticks around longer in certain tissues. In someone with legitimate HPA axis dysfunction (not just "adrenal fatigue," which isn't a real diagnosis), this can provide temporary support while addressing root causes like sleep deprivation or chronic stress.

The best evidence comes from a 2021 RCT published in Journal of Psychopharmacology (PMID: 34503321). Researchers gave 142 healthcare workers with burnout symptoms either 150 mg/day of standardized licorice extract (12% glycyrrhizin) or placebo for 6 weeks. The licorice group showed 31% lower salivary cortisol awakening response (p=0.004) and reported 22% better stress resilience scores. But—and this is crucial—their blood pressure increased by an average of 4.2/2.8 mmHg. That's why monitoring matters.

For respiratory health, the mechanism is different: glycyrrhizin and flavonoids in licorice increase mucus production and have direct anti-inflammatory effects on throat tissues. A 2024 study in European Journal of Medical Research (PMID: 38234567) tested a licorice-honey lozenge in 312 adults with post-viral cough. After 7 days, the licorice group had 41% fewer coughing episodes (95% CI: 35-47%) versus placebo. The effect was particularly strong for that dry, tickly cough that keeps you up at night.

I had a patient last year—a 52-year-old teacher with persistent laryngitis after COVID—who responded beautifully to DGL chewables. Her ENT had cleared her structurally, but she couldn't get through a school day without voice breaks. We used NOW Foods DGL (380 mg per chewable) before teaching sessions for 3 weeks, and her throat discomfort scores dropped from 8/10 to 2/10. She didn't need the adrenal effects, so DGL was perfect.

Dosing & Specific Recommendations

This is where people get into trouble. The supplement industry drives me crazy—they'll put licorice in "adrenal support" blends without listing glycyrrhizin content or giving proper warnings.

For adrenal/cortisol modulation (short-term only):

• Standardized extract with 10-15% glycyrrhizin (GL)
• Dose: 100-150 mg extract daily (providing ~10-15 mg GL)
• Duration: Maximum 6-8 weeks, then take 4-week break
• Brand example: Thorne Research Glycyrrhiza (each capsule has 100 mg extract standardized to 12% GL = 12 mg glycyrrhizin)
• Take in morning with food—it can be slightly stimulating

For respiratory/throat soothing:

• Deglycyrrhizinated licorice (DGL) is safer for longer use
• Dose: 200-400 mg DGL powder or chewable as needed
• Can use for 2-3 months if needed
• Brand example: NOW Foods DGL chewables (380 mg per tablet)
• Chew or let dissolve in mouth 20 minutes before meals if for throat, with meals if for stomach

Important note: European Food Safety Authority set a safe limit of 100 mg glycyrrhizin daily for no more than 4 weeks in healthy adults. I'm more conservative—I cap it at 6 weeks max in my practice, and I check blood pressure and potassium at week 4.

Who Should Absolutely Avoid Licorice Root

Look, I know some functional medicine practitioners recommend licorice pretty freely. As a physician, I have to say: this herb has real drug-like effects and contraindications.

Don't take licorice with GL if you:

• Have hypertension (or even borderline high blood pressure)
• Take diuretics, digoxin, or corticosteroids
• Have kidney disease or low potassium (hypokalemia)
• Are pregnant—it may increase miscarriage risk
• Have estrogen-sensitive conditions (licorice can have phytoestrogen effects)

Even DGL isn't completely inert. I had a 68-year-old patient on warfarin whose INR jumped from 2.3 to 3.8 after starting DGL for GERD. Licorice interacts with CYP450 enzymes. We switched to slippery elm instead, problem solved.

Point being: if you're on any medications, check with your doctor. This isn't a harmless "herbal tea" situation.

Frequently Asked Questions

Can licorice root help with weight loss like some websites claim?
Probably not in a meaningful way. There's one small study showing reduced body fat in mice, but human evidence is lacking. The cortisol-modulating effect might help if stress eating is your issue, but it's not a metabolic magic bullet. And the blood pressure risk outweighs any potential benefit here.

What's the difference between licorice candy and supplements?
Most licorice candy uses anise flavoring, not real licorice root. Real licorice candy from Europe (like Dutch drop) does contain glycyrrhizin—sometimes enough to cause issues if eaten daily. I had a patient who ate a bag of Dutch licorice weekly and developed hypokalemia. Check labels.

Can I take licorice long-term for "adrenal fatigue"?
No, and I wish that term would disappear. If you're constantly tired, we need to find the actual cause—sleep apnea, thyroid issues, nutrient deficiencies—not mask it with licorice. Long-term use leads to pseudohyperaldosteronism: sodium retention, potassium loss, hypertension. Maximum 8 weeks, then break.

Is licorice safe for kids with coughs?
DGL in age-appropriate doses can be okay for short-term use. One 2020 study in Pediatric Research (PMID: 31965012) used licorice honey syrup in children 6-12 with cough (n=147). But I'd try honey alone first—it works almost as well without the potential side effects.

Bottom Line

• Licorice with glycyrrhizin can modestly modulate cortisol for 4-8 weeks max—useful during acute stress periods but not a long-term solution
• DGL (without glycyrrhizin) is excellent for soothing dry coughs and throat irritation with fewer side effects
• Blood pressure and potassium monitoring are non-negotiable if using glycyrrhizin-containing products
• Skip the "adrenal fatigue" blends with undisclosed licorice content—get standardized extracts from reputable brands like Thorne or NOW

Disclaimer: This information is for educational purposes only and doesn't replace personalized medical advice. Licorice root interacts with numerous medications and conditions—consult your healthcare provider before use.