Chronic Fatigue Syndrome (CFS) and Licorice

Licorice root has been used across many traditions as an herbal treatment for many different conditions. Some herbalists or Traditional Chinese Medicine practitioners might recommend taking licorice root to treat chronic fatigue.

Based on the theory mentioned above that CFS might be related to low blood pressure, the herb licorice has been recommended for CFS by some herbalists. Licorice raises blood pressure (and causes other potentially harmful effects) when taken in high doses for a long time.

Read more details about Licorice.

Unfortunately, there is yet no evidence that it works for chronic fatigue syndrome, but this may be in part due to the fact that extensive research on licorice has not yet been conducted. However, other treatments to raise blood pressure have thus far proven to be ineffective for chronic fatigue syndrome.²⁴

Safety Issues

Use of whole licorice has not been associated with significant adverse effects in the short term. However, two or more weeks of use may cause high blood pressure, fluid retention, and symptoms related to loss of potassium. ¹ Such effects are especially dangerous for people who take the drug digoxin or medications that deplete the body of potassium (such as thiazide and loop diuretics ), or who have high blood pressure, heart disease, diabetes, or kidney disease.

Current evidence indicates that individuals who wish to take whole licorice on a long-term basis without any risk of these side effects should not consume more than 0.2 mg of glycyrrhizin per kilogram of body weight daily. ² For a person who weighs 130 pounds, this works out to 12 mg of glycyrrhizin daily. Based on a typical 4% glycyrrhizin content, this is the equivalent of 0.3 grams of licorice root.

Whole licorice may have other side effects as well. For example, it appears to reduce testosterone levels in men. ³ For this reason, men with impotence , infertility , or decreased libido may wish to avoid this herb. Licorice may also increase both the positive and negative effects of corticosteroids such as prednisone and hydrocortisone cream. ^{4 5} In addition, some evidence suggests that licorice might affect the liver's ability to metabolize other medications as well, but the extent of this effect has not been fully determined. ⁶ Whole licorice possesses significant estrogenic activity, ⁷ and some evidence indicates that licorice increases risk of premature birth. ⁸ For these reasons, it shouldn't be taken by pregnant or nursing women, or women who have had breast cancer.

Maximum safe doses for young children, nursing women, or those with severe liver or kidney disease have not been established.

It is believed, but not proven, that most or all of the major side effects of licorice are due to glycyrrhizin. For this reason, DGL has been described as entirely safe. However, comprehensive safety studies on DGL have not been reported.

Interactions You Should Know About

If you are taking:

• Digoxin : Long-term use of licorice can be dangerous.

• Thiazide or loop diuretics : Use of licorice might lead to excessive potassium loss. ⁹

• Corticosteroid treatment : Licorice could increase both its negative and positive effects. Do not take licorice internally if using corticosteroids.

• Aspirin or other anti-inflammatory drugs : Regular use of DGL might help lower the risk of ulcers.

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