[toc]Whether it’s Dr. Oz, Andrew Weil, or the Mayo Clinic talking about it, this root extract has been a trending topic in the media.
Some natural remedy websites purport it offers heartburn benefits which might rival omeprazole (i.e. Prilosec, Zegerid), ranitidine (Zantac), and lansoprazole (Prevacid).
In addition to using licorice for GERD (gastroesophageal reflux disease) and LPR (laryngopharyngeal reflux), you also hear some reviews claim it helps their stomach ulcers, H. pylori infections, gastritis, IBS, and to reduce gas and bloating.
But what does the science really say about this dietary supplement?
If the toxic compound has been removed, is it safe to use long term?
What is DGL licorice?
The difference between regular licorice root vs. DGL licorice is that with the latter, it’s deglycyrrhizinated. That means the plant’s poisonous glycyrrhizin compound has been almost entirely removed. This compound is considered bad for you, at least in excess, because it can cause high blood pressure and lower your potassium levels. Those side effects might be avoided by using a deglycyrrhizinated version (1).
Its most often sold in a supplement form and when used as directed, it is believed to be safe (2). Most foods have actually done away with natural licorice extract since it can be dangerous.
You will see the ingredients on Twizzlers, Red Vines and other candies don’t list licorice extract (and haven’t for decades). For the flavors trying to replicate the taste, they will list “natural flavors” which often includes the use of anise oil.
On the other hand, black licorice usually is the real deal and still does contain glycyrrhizin. In high dosages this compound is poisoning and an overdose is possible. That’s why the FDA warns people to “to avoid consuming large amounts” of the candy (3).
You can still enjoy the flavor safely, if you purchase the right kind.
Black licorice candy side effects can be avoided by using a 1/8th teaspoon of unsweetened pure DGL powder for flavoring, such as what Vital Nutrients sells.
If you want candy that’s premade, the only brand we know of is Meltzer’s. They use real licorice root extract in their mint pastilles, without all the glycerhizinic acid. Their pastilles also contain digestive-friendly anise, fennel, and cardamom. You can buy Meltzer’s on Amazon.
History of health benefits
The licorice root has been one of the 50 fundamental herbs in traditional Chinese medicine (TCM). They use the Glycyrrhiza uralensis plant (Chinese licorice) for allegedly detoxifying the spleen, stomach, and for helping with phlegm from coughing. They believe it replenishes qi (vital energy).
All of the TCM claims are unproven, but recently published research suggests it might “stimulate detoxification system via Nrf2 activation” (a signaling pathway in the body) (4).
The closely related and more common Glycyrrhiza glabra (traditional licorice) has been used for much of Ayurveda medicine’s history. Exactly how long is unknown, but they call it yashtimadhu. It’s often chewed when someone starts losing their voice as well as for digestive health (5).
There is a laundry list of other things they believe it helps too such as ulcers/wound healing, fertility (aphrodisiac and semen quality) and as a mild laxative (albeit not one that causes diarrhea).
As with the Chinese, the Ayurvedic claims have not been proven. Neither used it for weight loss, so how that concept came about is unknown.
In modern medicine, it was sold in Europe as part of an OTC treatment for peptic ulcers. Marketed under the name Caved-S, it was originally made by the German pharma company Viatris (now owned by Meda) (6). Here was the ingredient list for each Caved-S chewable tab (7):
- 380 mg of DGL licorice
- 100 mg bismuth subnitrate
- 100 mg aluminum hydroxide gel
- 200 mg magnesium carbonate
- 100 mg sodium bicarbonate
- 30 mg powdered frangula bark (Alder buckthorn)
This product was popular in the 70’s through the 90’s. After the invention of proton pump inhibitors (PPIs) like Prilosec and others, the popularity of Caved-S weened and it was eventually discontinued.
On the topic of it and similar remedies, the European Medicines Agency said the following in 2011: There are no clinical data in the scientific literature to support a “well-established medicinal use.”
Caved-S was not marketed in the United States. DGL licorice tablets for acid reflux (or any other disease) have not been evaluated by the FDA. Licorice has only been sold as a dietary supplement and therefore…
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
For the digestive supplements consisting of multiple ingredients, you will see many that combine slippery elm, aloe vera juice, or mastic gum and DGL licorice, since those plants are believed to be beneficial (albeit also unproven). Additionally, the Mayo Clinic mentions chamomile and marshmallow extract on their alternative medicine page about GERD (8).
The popularity of these combos are not surprising given that media darlings like Dr. Weil have discussed mastic gum and Dr. Oz has highlight slippery elm for GI disorders. Yet just the plain ol’ licorice root – preferably in the deglycyrrhizinated form – might offer some unique advantages those other plants don’t.
So what evidence is there to suggest chewables and capsules might be effective or beneficial as a dietary supplement? Let’s take a look…
Surprisingly high in antioxidants
To be clear, this has nothing to do with gastrointestinal side effects, but it’s fascinating nonetheless.
The ORAC value, which is an in vitro measurement of antioxidant activity, is very high for this root extract. Dried Glycyrrhiza glabra (the same kind used in confectioneries and supplements) measures out at 102,945.
That’s almost the exact same as pure acai powder, which is 102,700.
Everyone hypes acai bowls as being a superfood, when in reality they’re often loaded with added sugars. The 24 oz. Jamba Juice Açaí Primo Bowl has almost the same amount of sugar as 2.5 cans of Coke!
The ORAC value of the licorice deglycyrrhizinated has not been measured, but even after processing, it still likely would contain a high amount of antioxidants.
Because given natural licorice’s starting value of 102,945, even if 90% of the antioxidants were destroyed in the process, you would still have more antioxidants than raw ashwagandha root (8,487), maca (6,100), and spirulina (5,970)
Theories of gastrointestinal advantages aside, the high amount of antioxidants make real licorice a superfood worthy in its own right.
Licorice for acid reflux?
It’s understandable why many seek natural remedies to get rid of heartburn.
Long term use of proton pump inhibitors (PPIs) have been shown to interfere with the absorption of vitamin B12, iron, calcium, magnesium, zinc, and folic acid (9) (10) (11) (12).
Plus, there are lesser known possible side effects with PPI’s, such as increased risk for bone fractures, pneumonia, interstitial nephritis (kidney inflammation), and enteric infections (like E. coli, Salmonella, and Streptococci) (13).
Does DGL licorice help acid reflux, like those synthetically created meds? No and people who claim that are not basing their opinion on human clinical trials. Those haven’t even been done!
That being said, while it remains unproven, there is evidence to suggest this root might help to some degree, with few or even no side effects.
It may have been used for ages in Ayurveda, but modern science has found how licorice works; the theory is that it reduces inflammation and inhibits certain enzymes which may worsen symptoms, such as heartburn (14). Luckily, those benefits appear to be unrelated to the dangerous glycyrrhizin compound (15):
“G. glabra (almost devoid of glycyrrhizin) exhibits anti-inflammatory property likely through the inhibition of PGE(2), TXB(2) and LTB(4) in mammalian cell assay system….”
Those are activated or released by cells in response to inflammation.
While it is possible to patent methods of processing this root, the extract – or active ingredients – which come from it are not eligible for patent protection.
Considering that, it’s no surprise only a handful of controlled studies on humans have been done and they involve branded combinations, instead of this ingredient on a stand-alone basis.
Caved-S studies
While no longer made, this branded OTC remedy mentioned above was sold for decades in Europe, Canada, and South Africa.
Initially, the research from the 1970’s did not find it to have a healing effect on stomach ulcers (16). However a more extensive clinical study done during the 1980’s suggested its long term effects might be comparable to cimetidine (Tagamet), which was one of the most popular OTC heartburn medications during that era. Cimetidine is a H2 receptor antagonist which reduces stomach acid.
A 1982 single-blinded study involving 100 patients compared 1g of cimetidine versus 6 tablets of Caved-S per day. Cimetidine only worked better during the first 2 weeks for night pain. Based on metrics at 6 and 12 weeks, for the side effects of gastric ulcers it was said (17):
“There was no significant difference between the two drug regimens”
After the first year of continued use, the rate of ulcer occurrence in each group was the same (14%).
Based on a 1985 double-blinded controlled study with another 100 patients, using Caved-S licorice with Zantac’s active ingredient (ranitidine) did appear safe, but there didn’t seem to be any added benefit for the healing or prevention gastric ulcers (18).
After 2 years of taking Zantac’s compound (150 mg nightly), both with and without Caved-S twice daily, the difference in the recurrence rate was still not significant. No serious side effects had been experienced, but this confirmed there was no added benefit in taking both together (19).
While the history of Caved-S is interesting, unfortunately it’s not an apples to apples comparison. That OTC treatment contained proven antacids along with the unproven herbal ingredients. Some also believe it was a low dosage of DGL per tablet, relative to some pure supplements for sale today.
Licorice vs. placebo for upset stomach
Functional dyspepsia (FD) is the medical term for the feeling of movement in the upper digestive tract, near the ribs.
Different than the sensation of heartburn, dyspepsia is one of the most common side effects of acid reflux/GERD. Using a branded supplement for DGL called Gutgard, researchers wanted to see if might improve this problem (20).
- Randomized, double blind, and placebo controlled study.
- 50 adults were given the supplement or a placebo.
- The supplement group received a daily 150 mg dosage (75 mg twice daily).
- For 30 days, each group took their pills.
The results?
Those on the licorice extract experienced a 55% decrease in their symptom score, compared to only a 19% decrease for placebo.
For what they call the global efficacy score (patients without symptoms or with “marked improvements”) they found a 0% improvement for the placebo group, versus a 56% improvement for the DGL group. Adverse side effects were not reported.
Atherosclerosis
This is the hardening of your arteries as you age, due to the buildup of plaque.
In the past, doctors believed there wasn’t much which could be done to prevent this disease. During the past couple of decades research has found that actually, diet may greatly influence the rate of atherosclerosis.
One of the factors contributing to the disease is bad cholesterol; the LDL form (26).
Lipid peroxidation (the oxidation of LDL cholesterol) has been found to be “a crucial step in the pathogenesis of atherosclerosis” (27).
One of the least known theorized benefits of licorice which may turn out to be the most impressive – how it might reduce LDL oxidation. So far, two human studies seemed to have demonstrated this.
The first was a double-blind study involving 19 young adult males. How much licorice was taken per day was not much, just 60 mg of the extract. This was used for 6 months and the result was a 20% reduction in LDL oxidation (28).
The other was a short term cohort study involving 10 men who took 100 mg daily for 2 weeks. During that time there was a 33-44% increase in lag time to oxidation (29).
While both are small studies, the differences observed are profound. Obviously much more research is needed to validate this suspected benefit. If it turns out to be the real deal, perhaps it’s the high antioxidant content of licorice (and the types it contains) which are responsible for reducing LDL oxidation.
Can it help H. pylori infections?
Helicobacter pylori is a spiral-shaped bacteria that is found in the digestive tract. Generally, its presence is considered benign. Yet when it runs rampant, the CDC says it is the cause of up to 80% of gastric ulcers and 90% of duodenal ulcers (the first part of the small intestine) (21).
Does DGL licorice kill H. pylori? There is evidence to suggest it might. So far the research is very preliminary and involves non DGL licorice, but both would be expected to have the same or similar effect on the bacteria, if it works.
A double-blind study evaluated 40 patients with peptic ulcers and the presence of H. pylori. They were divided into 2 groups (22).
The first group received:
- amoxicillin (antibiotic) – 500 mg taken 3 times/day, after eating (15 days)
- metronidazole (antibiotic) – 250 mg taken 4 times/day, after eating (15 days)
- omeprazole (Prilosec) – 20 mg taken 2 times/day, 30 minutes before eating (30 days)
- bismuth subnitrate (for peptic ulcers) – 500 mg taken 3 times/day, 30 minutes before eating (30 days)
The second group received the same regimen, except with licorice in place of the bismuth subnitrate.
The results?
“Our findings showed that licorice could be suggested as a replacement in treatment for quadruple therapy when this regimen is not available while licorice has a low-cost, highly tolerable and with minimal side-effects.”
A year later in 2014, a similar study involving 60 patients concluded the same and also said “it may also be effective in resistant strains” (23).
How does the licorice help? 2016 research using gerbils found it (24):
“…significantly attenuated H. pylori-infected gastritis in gerbils and has the potential to be developed as a new therapeutic drug.”
They said this because of the root’s apparent effect on their gastric mucous membrane – a barrier against the H. pylori bacteria. How long does it take DGL licorice to work may have something to do with that – the time it takes for the healing of the gastric lining.
If further research validates this, that could explain why licorice as a purported instant natural remedy for acid reflux is not something you hear. How long it takes to work may be several weeks at minimum, if it ever ends up being studied and validated in a clinical setting.
Research in 2017 out of India found that the flavonoid-rich extract of the root seemed to work well with the gut friendly probiotics found in humans (25).
Side effects
Before removal of the dangerous glycyrrhizin poison, eating as little as 2 ounces per day of black licorice for 2 weeks might give you an irregular heart beat (arrhythmia) if you’re over the age of 40.
That’s according to a warning on the FDA’s website (30). But is DGL licorice safe, since the compound has been largely removed?
Here’s what the National Center for Complementary and Integrative Health (NCCIH) says about the root’s safety (31):
“In large amounts and with long-term use, licorice root can cause high blood pressure and low potassium levels, which could lead to heart and muscle problems. Some side effects are thought to be due to a chemical called glycyrrhizic acid. Licorice that has had this chemical removed (called DGL for deglycyrrhizinated licorice) may not have the same degree of side effects.”
That’s all they say on the topic and the word “may” is not very helpful in that context. It’s not clear what their definition of removal is.
How much glycyrrhizic acid there is in licorice root will naturally be between 6% and 14% (32). Given how toxic it is, there still may be a relatively high amount of this poison in some candy, even after you factor in the root extract being heavily diluted with sugar and flour.
The percentage of glycyrrhizic acid may be as high as 3% in the pure supplements which remove it, while some have almost none, such as Kaneka’s ‘Glavoinoid Rich Oil’ which they sell to some supplement companies for use in capsules. Kaneka’s process leaves under 0.005% glycyrrhizin.
Paperwork filed with the FDA by Kaneka claims their product “generally had no adverse effects” (33).
Obviously there’s a big difference between a product that may be 3% or 0.005%. For that reason, it’s unfair to lump all of these “deglycyrrhizinated” products together when really, some probably shouldn’t be called that term to begin with!
Too much or an overdose of DGL licorice is not documented in medical literature, or at least there’s nothing about it in the NIH’s PubMed database. Regardless, you should not assume high quantities are risk free. To be safe, you should only use the manufacturer’s recommended dosage/serving size.
While the cardiovascular problems are believed to be linked to the glycyrrhizic acid, ultimately little is known about what other potential reactions might happen separately. Here are a couple to consider…
Drug interactions
Can DGL licorice raise blood pressure? It’s not known to do so on its own, but once you factor in medications, the answer becomes less clear.
When it comes to regular licorice with the glycyrrhizin still intact, there are known interactions, including (34):
- Angiotensin-converting enzyme (ACE) inhibitors or diuretics – May decrease effectiveness of these.
- Anticoagulants – May interfere with warfarin and other medications for preventing blood clots.
- Corticosteroids – May worsen side effects.
- Insulin – May worsen side effects.
- Laxatives – May increase potassium loss.
- Oral birth control – May cause lower potassium and higher blood pressure.
- Digoxin – Users of this herbal supplement are known to experience problems when mixing.
It is unclear which of these issues – if any – might occur with both the DGL and non DGL licorice.
For example, the reports of women on birth control pills experiencing lower potassium and higher blood pressure with regular licorice are documented. Whether the same has happened with birth control and DGL is unclear.
Given the lack of side effects for deglycyrrhizinated being documented, you should consult your doctor before using if you are on any prescriptions.
Likewise if you plan to take DGL licorice with omeprazole or another medication for GERD, even if it’s one that’s over the counter like Prevacid or Zantac. There are reviews which claim to successfully use both together without interaction, but everyone’s circumstances are different so you shouldn’t do the same unless your doctor gives you the go ahead.
Estrogenic effect
Does it lower testosterone?
Soy is often assumed to be the best (or worst, if you’re a man) phytoestrogen food, however flax seeds have over 300% more activity.
Among supplements, black cohosh is often used post-menopause, but research has shown that licorice estrogen dominance is also significant and might offer a similar benefit of some degree (35). Though for men and women not wanting that, this would be a side effect.
The good news?
Research suggests it’s the plant steroid glycyrrhizin, in glycyrrhetic acid, which appears to be the biggest cause of the anti-androgen effect and it’s “weak” at that (36) (37) (38). The licorice testosterone blocker concern should be much less of a worry for versions that remove the glycyrrhetic acid.
Even for those who eat black licorice which contain the full amount, estrogen boosting or testosterone lowering should be of little concern:
- The effect of glycyrrhizin on free testosterone in men is unknown. In animal studies, it took extremely high amounts relative to their body weight (39) (40).
- When you eat the candy, it’s mostly sugar and not a concentrated form of the root.
- For most people, the candy is not a daily or even weekly treat.
Is DGL licorice safe during pregnancy?
In 2009, the University of Edinburgh published a study which found that women who ate 500 mg of glycyrrhizin per week were more likely to have children with a lower IQ and/or behavioral problems like ADHD (41).
That was based on 321 mothers who had 8 year old kids. Out of them, 64 were said to have eaten large amounts during their pregnancy – a weekly equivalent of at least 3.5 ounces of black licorice candy. 46 of the mothers had a lower “moderate” consumption.
Why do they think that happened? The scientists suspect the glycyrrhizin affected the placenta, allowing stress hormones from the mother to enter the womb and be absorbed by the baby.
Even though this is only one study and a theory, it deserves attention.
If you’re a pregnant woman or are trying to get pregnant, to be safe you should avoid authentic licorice altogether. Even supplements made with the DGL version should be avoided, since a minuscule amount of glycyrrhizin will still be present.
How much DGL should I take?
If you choose to use licorice supplements for acid reflux or another purpose, remember that and other health benefits are currently unproven. You will see different strengths/dosages for sale of these supplements:
200 or 300 mg per serving on the low end, 450 to 500 mg for mid-range, and 770 mg for those marketed as “high potency.” Depending on the brand, some of those serving sizes may entail more than one capsule or chewable tablet.
For non-pregnant healthy adults, the common side effects of licorice don’t seem to be observed with these dosages. So staying within the daily dose listed on the supplement facts label – and not exceeding it – seems like a good idea.
When it comes to food sources, whether it’s Red Vines black licorice, a higher end brand like Panda, or one that’s organic, they’re almost always made with wheat flour.
The nice thing about making from scratch using gluten free DGL powder is that it can be 100% celiac friendly AND contain dramatically lower amounts of the glycyrrhizin. Orgran GF licorice, the only brand we know of that is wheat free, doesn’t even use deglycyrrhizinated. So a homemade recipe is your only option for that!
If you do choose to make candy or other confectioneries, make sure the amount you eat per day of the powder remains within the serving size listed on its label.
Where to buy (and which brand)
You’re unlikely to find a DGL supplement for sale at Walmart, Trader Joe’s, and other discount retailers. Vitamin Shoppe, Vitamin World, and Whole Foods do carry a couple brands, as well as some Walgreens and CVS locations.
Not many manufacturers make it. It’s noticeably absent from the product lines of Nature Made, Nature’s Way, Kirkland (Costco), and Jarrow Formulas, just to name a few.
Review the label carefully because you will see that some of these same brands sell a pure licorice supplement, not the safer version with the glycyrrhizin removed. Nature’s Way is one example.
Not all products will be vegan or vegetarian. A few contain milk and use gelatin capsules.
Some sell similar alternatives, like Jarrow Formulas mastic gum (some people use mastic gum and DGL licorice together).
If you’re looking for organic DGL you will be out of luck, because we’re unaware of anyone who makes it. This is most likely because of the inevitable processes which are necessary to remove the glycyrrhizin.
For the capsule form, the best DGL licorice brands include Enzymatic Therapy, Natural Factors, Now Foods, Planetary Herbals, Puritan’s Pride, Solaray, Solgar, Swanson, and Thorne. You can also buy it from Life Extension, as part of their EsophaCool chewable formula which contains other useful ingredients.
Based on our reviews, we like the chewable Enzymatic Therapy tablets the most. This vegetarian formula is soy free, dairy free, and yeast free. For diabetics, they also have a sugar free version available on Amazon.
Available in a lower dosage is Natural Factors chewable, which may be a better idea for those using it for the first time.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.