Guggul products are derived from the gum resin of the small, thorny mukul tree (Commiphora mukul) of India's semi-arid plains. The mukul tree is related to another tree (Commiphora molmol and C. myrrh) whose bark is the source for myrrh, another gummy substance with healing properties. Guggul gum is used to produce standardized or purified extracts called gugulipids or guggulsterones. Heart drugs based on guggul extracts are sold in India, where almost all of the research on guggul has been done in the past thirty years.