Guggul (or gum guggul) is the yellowish resin produced by the mukul myrrh, a thorny shrub native to India and the Middle East. Approximately 6 to 8 feet in height, the mukul myrrh is essentially leafless most of the year. When present, the leaves consist of one to three small, ovate leaflets with serrated edges. Mukul myrrh has small, brown to pink, unisexual flowers, which eventually give way to red, ovate fruit, each containing a single seed. Upon injury, the shrub exudes a resinous substance, or guggul, which is used for health purposes.
The active constituents in guggul are a group of compounds known as guggulsterones.
Most studies on guggul have used doses providing the equivalent of 25 mg of guggulsterones twice daily. Side effects such as headache, mild nausea, belching, and hiccups have been reported in a small number of patients. Because guggul may interfere with the activity of some drugs, people taking prescription medication should only take guggul under a physician's supervision.