Synephrine HCL, synonymously referred to as Bitter Orange, or oxedrine, is a nutritional supplement commonly used for weight loss and substitute for the now restricted drug ephedrine.

 It appears in fat burners as "synephrine hcl", or it can be derived from citrus aurantium, also known as "bitter orange." Bitter orange has been used in traditional Chinese medicine and by indigenous people of the Amazon rainforest for nausea, indigestion, and constipation. 

Current uses of bitter orange are for heartburn, loss of appetite, nasal congestion, and weight loss. It is also applied to the skin for fungal infections such as ringworm and athlete's foot. The commonly recommended dose for Synephrine HCL is extremely small