Even if you have never heard of it before, chances are you drank it. Glucuronolactone is a naturally-occurring substance and a lesser-known ingredient in energy drinks like Red Bull. It is also added to pre-workout supplements touted to increase physical performance, stamina, endurance, and detox. Find out if the popular claims about its benefits are valid and learn the potential dangers. What Is Glucuronolactone?
Glucuronolactone is a normal product of glucose breakdown in the liver. All connective tissues contain it, as well as many plant gums. The amounts found in food and those produced in the body, though, are negligible compared to the dosage in energy drinks and supplements [ 1 ].
Glucuronolactone is an ingredient in certain energy and sports drinks, such as Red Bull. As a supplement, it’s available in the powder/capsule form.
It is advertised as a supplement to enhance athletic performance, detoxify the liver, and reduce mental fatigue. However, clinical research about the specific effects of this compound is scant. Snapshot
Naturally occurring substance
No reported side effects and toxicity
Might have heart- and liver-protecting benefits
Might aid in cancer prevention
Combined with potentially harmful ingredients into energy drinks
Lack of clinical trials
Very few animal studies
Animal studies only examined its breakdown products
What Does Glucuronolactone Do?
Glucuronolactone converts to glucuronic acid in the body. This conversion occurs back and forth; there are equal amounts of each molecule in the body [ 2 ].
Glucuronic acid is involved in detox and the breakdown of glucose, as part of a specific pathway crucial for creating fatty acids, amino acids, and DNA components (known as the Pentose Phosphate Pathway) [ 3 ].
Upon glucuronolactone ingestion, glucuronic acid levels (in both blood and urine) will rapidly increase [ 4 ].
Glucuronic acid plays a key role in a detox pathway known as glucuronidation . It binds to chemical and environmental toxins, pharmaceutical drugs, and cancer-causing molecules. By joining with glucuronic acid, these toxins become [ 5 , 6 , 7 ]: More soluble
Transported faster in the body
Eliminated through urine or feces
Another product of glucuronolactone breakdown is called D-glucaro-1,4-lactone. About 25% of glucuronolactone is quickly converted to it. This compound is a potent inhibitor of beta-glucuronidase , an enzyme dominantly produced by your gut bacteria . Various tissues can also make it in lower amounts (the liver, spleen, kidney, gut, endocrine glands and sexual organs) [ 1 , 8 +].
Gut bacteria that make beta-glucuronidase can break down complex carbohydrates. However, this enzyme reverses the glucuronidation process, which slows down detox. Its levels rise with exposure to chemical and environmental pollutants, such as tobacco smoke and heavy metals [ 9 , 10 ].
High levels of beta-glucuronidase may point to [ 11 ]: Liver inflammation and cirrhosis Liver inflammation Tuberculosis Cancers: brain, colon, pancreatic, breast and prostate Potential Benefits of Glucuronolactone No valid clinical evidence supports the use of glucuronolactone for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit. 1) Exercise Performance The effects of glucuronolactone on exercise performance and endurance have been studied in humans, but only as an ingredient in functional energy drinks.Taking a pre-workout energy supplement (mix of caffeine, taurine, glucuronolactone, beta-alanine , creatine , and amino acids) 10 minutes before resistance exercises significantly increased workout performance in eight resistance-trained men [ 12 ].In a clinical trial of 12 trained cyclists, consumption of Red Bull energy drink 40 minutes prior to exercise increased endurance and overall physical performance [ 13 ].That said, energy drinks contain numerous ingredients aside from glucuronolactone, including caffeine , taurine , glucose, and B-vitamins. Therefore, the observed benefits cannot be attributed to glucuronolactone alone. In a rat study, high doses of glucuronolactone enhanced physical performance and increased stamina given shortly before swimming exercises [ 14 ]. 2) Cognition (Nootropic Effects) In a study of 36 participants, drinking Red Bull (composed of sugar, taurine, glucuronolactone, and caffeine) led to significant improvements in attention, concentration, and memory [ 15 ].Drinking Red Bull improved driving quality, reduced variation in speed, and lowered mental strain from prolonged driving in 24 healthy volunteers [ 16 ].In an observational study of 10 graduate students, drinking Red Bull led to faster motor reaction time, improved attention and decision making when compared to the control group [ 17 ].Once again, Red Bull contains caffeine and other active ingredients that likely contributed to these results. In the lack of clinical research, we can’t estimate the nootropic effects of pure glucuronolactone. No clinical evidence supports the use of glucuronolactone for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based studies; they should guide further investigational efforts but should not be interpreted as supportive of any health benefit. 1) Blood Clotting and Antioxidant Protection In a study on human plasma, a product of glucuronolactone breakdown (D-glucaro 1,4-lactone) decreased damage to the blood proteins caused by free radicals. It reduced the excessive clumping of platelets that can lead to heart disease and stroke. This effect is amplified in combination with the antioxidant resveratrol , found in red wine [ 18 , 19 , 20 ]. 2) Liver Detox Glucuronolactone might protect the liver by enhancing the glucuronidation detoxification pathway.In rats with liver disease, D-glucuronolactone lowered liver inflammation ( IL-6 , NF-κB ) and tissue injury markers. In addition, it increased antioxidant liver enzyme activity ( SOD , glutathione , and glutathione peroxidase ) [ 21 ]. 4) Cancer Prevention Supplementation with a glucuronolactone breakdown product (D-glucaro 1,4-lactone) inhibited breast tumor growth in rats [ 22 ].In rats with liver cancer, the same compound increased survival rates from 45% to 70%. It also reduced the levels of a cancer marker, alpha-fetoprotein [ 23 ].Glucuronolactone plays a role in detoxifying the body from […]