A Spotlight on Black Licorice and its Darker Side

Black licorice. You either love it or you hate it. Some delight in the intense spice flavor that comes with a bite of licorice and others find it repulsive and gag at the mere scent of it. As a divisive food and old-timey treat, black licorice has a long history of being a chewy confectionery and a popular flavor for drinks and tobacco in many parts of the globe. Licorice (scientifically referred to as Glycyrrhiza glabra) is a flowering plant that comes from the legume family. Its roots contain the flavor that we know as licorice and are commonly extracted for various uses. While it shares similar flavoring compounds, it is not related botanically to anise or fennel as some may think. (though sometimes they are used instead of licorice to evoke the same flavor profile)

What makes black licorice so sweet?

The iconic scent and flavor of licorice come from a mix of different compounds, but the one that gives it most of its sweetness is glycyrrhizin (a compound that is about 50 times sweeter than sugar!) This sweetness is different than regular sugar in that it more closely resembles sweeteners like Sweet ‘n’ Low which is comprised of saccharin. Some people vehemently dislike this type of sweetness which is also known to linger on the tastebuds for longer. Many people claim to dislike how “sickeningly sweet” it is and feel that it strongly dominates whatever you taste in your mouth for many minutes even after it is consumed. Others say that their aversion comes from the glycyrrhizin tasting more bitter than sweet.

This bitterness can be attributed to herbal medicine, which licorice is also known to be useful for. There are many patented licorice-based medicines in China, where its extract is used in the treatment of bronchitis, colds, cough, and upper respiratory diseases. Glycyrrhizin, glycyrrhizinic acid, isoliquiritin, and glycyrrhizic acid are the most notable substances used for health benefits as they possess anti-cancer, anti-microbial, and anti-inflammatory properties. Excessive consumption that allows for the build-up of these compounds, however, may lead to serious adverse health effects.

Consequences of Overconsumption

Like most things in life, licorice is best enjoyed in moderation, but for more sinister reasons than you may think. Eating more than 57g of black licorice a day for at least 2 weeks could potentially cause serious health problems, such as an increase in blood pressure and an irregular heart rhythm (arrhythmia). This happens because of an excess of glycyrrhizic acid in the body. Normally your body is able to process glycyrrhizic acid into glycyrrhetinic acid, which is relatively harmless in small amounts, but when larger concentrations are present in the body, it can inhibit an enzyme that assists in converting active cortisol (the hormone that controls adrenaline) into inactive cortisone. You can imagine what too much active cortisol might do to your body, and this imbalance like this can wreak havoc on your body. 

Cortisol is a hormone that plays a role in your fight-or-flight response and is similar chemically and structurally to aldosterone, which during a stressful event can signal to the body to hold on to water if you’re dehydrated. It does this by binding to structures in the kidneys that cause sodium to be pulled from urine in order to trigger osmosis and cause water to stay in your cells. Sodium has a +1 charge, however, and if it’s taken from the urine, then another +1 charge must replace it. This is done by potassium which can then replace the sodium in the urine and be excreted from the body. Now, when cortisol is present in concentrations that are dangerously high, it can be concluded that it would cause your body to pull more sodium from your urine, and you would lose more potassium right? 






Cortisol (left) & Aldosterone (right)

This leads to hypokalemia or low potassium presence in blood, which can be detrimental to the muscles of your body especially one of your most essential muscles, your heart. Potassium is an ion in your body that signals a relaxation of your muscles after a contraction. If there isn’t enough potassium present in your blood, then your muscles will stay contracted, which can be especially bad for your blood vessels and your heart. This is where the increased blood pressure and arrhythmia can restrict proper oxygen flow throughout your body and cause your organs to shut down.


No Need to Panic

Now, of course, the chances of this happening to the average black licorice fan are very slim as long as the treat is enjoyed in moderation. Since most people wouldn’t eat 57g of black licorice every day, I think it’s safe to say that fearing death by licorice overdose won’t be found in anyone’s nightmares. All in all, black licorice is a novel sweet with an interesting chemical makeup that is loved (or hated) by many across the globe.



Pastorino G, Cornara L, Soares S, Rodrigues F, Oliveira MBPP. Liquorice (Glycyrrhiza glabra): A phytochemical and pharmacological review. Phytother Res. 2018 Dec;32(12):2323-2339. doi: 10.1002/ptr.6178. Epub 2018 Aug 17. PMID: 30117204; PMCID: PMC7167772.

Wahab S, Annadurai S, Abullais SS, Das G, Ahmad W, Ahmad MF, Kandasamy G, Vasudevan R, Ali MS, Amir M. Glycyrrhiza glabra (Licorice): A Comprehensive Review on Its Phytochemistry, Biological Activities, Clinical Evidence and Toxicology. Plants (Basel). 2021 Dec 14;10(12):2751. doi: 10.3390/plants10122751. PMID: 34961221; PMCID: PMC8703329.



Abby is a 3rd-year undergraduate student at Georgia Tech majoring in Biology with a pre-med track. She loves all things biology from bacteria and cells to plants and animals. In particular, she enjoys learning about pathology and molecular biology and hopes to one day work in the medical field where she can learn forever. In her free time, Abby enjoys doing arts & crafts with her enormous sticker collection, watching mystery shows, and finding tasty restaurants to try with her friends.