Licorice Root Side Effects: 7 Ways It May Harm Your Health

Reviewed By Registered Dietitian Nutritionist Julie Freeman, MA, RDN, LDN, RYT
by Ravi Teja Tadimalla

Licorice root extract has a sweet flavor and is a popular ingredient in candies and other beverages. Though it seems to offer certain benefits, excess intake may cause harm. Research shows that over-intake of licorice can lead to elevated blood pressure levels and headaches.

There is more information on licorice root side effects that tell us why it may not be the right choice for all. In this post, we have covered the most common side effects that excess of licorice can cause.

What Are The Side Effects Of Licorice Root Extract?

1. May Elevate Blood Pressure Levels

There are several studies to back this up. Some reports recommend individuals with high blood pressure to avoid licorice root extract altogether.

It is often linked to salt and water retention as it suppresses aldosterone – which is a hormone responsible for controlling sodium levels in the body. One study stated that licorice tea caused hypertension in patients, and quitting it resolved the condition in two weeks (1).

Licorice was also identified as a root cause of secondary hypertension. The root contains glycyrrhizic acid, which contributes to its pro-hypertensive properties (2).

2. Might Cause Constipation

Excess amounts of licorice root extract can lead to hypokalemia (low levels of potassium), with constipation being one of its symptoms (3), (4).

The onset and severity of the symptom usually depend on the dose and duration of licorice intake (3).

It is believed that licorice may cause diarrhea or aggravate irritable bowel syndrome in some individuals. However, there is no sufficient information to prove this effect. If you have any bowel issues, please check with your doctor before consuming licorice (as there is a possibility that you may react to it negatively).

3. May Lead To Headaches

The glycyrrhizin is the culprit. It is known to trigger headaches. A Massachusetts study found that excessive consumption of the extract could lead to the constriction and dilation of cerebral arteries, often leading to thunderclap headaches (5).

In rare cases, it is complicated by hemorrhagic strokes (5). Though the condition is reversible, the symptoms can be severe.

4. May Lead To Dizziness And Fatigue

A study published in the Journal of Clinical Neurology and Neurosurgery reported the development of hypertensive encephalopathy in a 15-year-old boy after ingestion of a candy containing licorice (6).

This form of hypertension is accompanied by vomiting, dizziness, headaches, and visual problems (7).

Licorice may also cause apparent mineralocorticoid excess, another condition characterized by hypertension. The symptoms of this condition include dizziness, headaches, and general and muscular fatigue (8).

5. May Cause Hormonal Imbalances

Mice studies have shown that isoliquiritigenin, a compound in licorice, may cause Hormonal Imbalance by interfering with the sex hormones in the ovaries. It may disrupt the production of sex hormones (9).

One major reported side effect of licorice root is reduced levels of testosterone in men (10). Some believe it may also increase estrogen and prolactin levels in women, though more research is warranted.

6. May Harm Baby During Pregnancy

Studies show that licorice consumption during pregnancy may harm the developing offspring (11).

Adolescents exposed to large amounts of licorice when in the womb performed less well in cognitive tests (11).

The glycyrrhizin in licorice was also found to be associated with preterm delivery. Hence, pregnant women are suggested to stay away from licorice (12). Some experts believe that licorice can induce preterm labor by mimicking the effects of estrogen (the female sex hormone). However, we need more research in this regard.

Licorice is also believed to cause miscarriage. There is no evidence to support this information, though.

The effect of licorice in breastfeeding women has not been studied well. Hence, breastfeeding women should avoid it.

7. May Cause Allergic Reactions

Excess licorice intake has been associated with allergies like asthma and contact dermatitis (13). It may also interfere with blood-thinning medications like warfarin (13).

Anecdotal evidence suggests that those allergic to peas or legumes may also be allergic to licorice. However, research is limited to support this data.

How Much Licorice Root (in mg) Is Safe?

The actual dosage of licorice could be hard to determine as it is available in various forms, including candies, supplements, and beverages. As per the European Union, 100 mg/day is the upper limit for the intake of glycyrrhizin, which is present in about 70 grams of licorice (13).

Another study has declared the safe upper limit of licorice to be 1 to 5 grams per day (13).

Given the ambiguity, you should consult your doctor regarding licorice dosage.


Licorice root is available in different forms – as a root extract, powder, and licorice tea. Its adverse effects could be serious, more so in pregnant and breastfeeding women. Please avoid licorice intake if you are likely to be affected by its side effects. If you are a healthy individual and choose to consume licorice, consult your doctor regarding the dosage.

Expert’s Answers For Readers’ Questions

Does licorice cause weight gain?

There is no information that licorice may cause weight gain. In fact, some research states that it may help slow down weight gain. The effects were more pronounced with licorice root powder (14).
It is believed that licorice may affect the hormones related to metabolism, and this may lead to unhealthy weight gain. However, there is no research to support this.

Does licorice damage the liver?

Anecdotal evidence suggests that individuals with liver disease must stay away from licorice. There is no research to back this up. In fact, one rat study states that licorice could actually be beneficial for the liver (15).

15 sources

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Ravi Teja Tadimalla

Ravi Teja Tadimalla is a Senior Content Writer who specializes in writing on Health and Wellness. He graduated from SRM University, Chennai, and has been in the field for well over 4 years now. His work involves extensive research on how one can maintain better health through natural foods and organic supplements. Ravi has written over 250 articles and is also a published author. Reading and theater are his other interests.