Aegeline, also known as N-[2-hydroxy-2(4-methoxyphenyl) ethyl]-3-phenyl-2-propenamide, is an ingredient that has been added to some dietary supplements, especially ones marketed for weight loss and muscle building. Naturally found in the Aegle marmelos (bael) tree, which is used in Ayurvedic medicine, aegeline also can be synthesized (created in a laboratory). Some research studies (animal and laboratory) suggest this plant might have anti-cancer, anti-inflammatory, and antioxidant properties, but we have found no studies reporting aegeline’s effectiveness for weight loss or muscle development in humans.
In 2013 FDA issued a warning letter about aegeline in two dietary supplement products, because it was not receognized as a legitimate ingredient for dietary supplements. At that time dietary supplements with synthetic aegeline had been associated with 90+ cases of acute liver injury, some even leading to death. Since then, studies with animals have shown that products containing ageline can result in hepatotoxity. Less severe side effects include fatigue, nausea, and jaundice. More information is provided in this LiverTox article from the National Institutes of Health.
The concentration of aegeline in dietary supplements is likely higher than in nature, so aegeline’s “long history of use” in traditional medicine is not sufficient evidence for safety. Furthermore, individual ingredients in a dietary supplement formulation might be safe at the amounts used, but when combined with ingredients might produce serious side effects. One such example was OxyELITE Pro (New Formula; available in 2014), which contained aegiline together with other ingredients. Because there is insufficient information about the safety of aegeline, use of products with this ingredient is discouraged.