Diethylpropion is a sympathomimetic stimulant drug marketed as an appetite suppressant. Chemically, it is the N,N-diethyl analog of cathinone. Its mechanism of action is similar to other appetite suppressants such as sibutramine, phentermine and dextroamphetamine. Diethylpropion is an amphetamine that stimulates neurons to release or maintain high levels of a particular group of neurotransmitters known as catecholamines; these include dopamine and norepinephrine. High levels of these catecholamines tend to suppress hunger signals and appetite. Diethylpropion (through catecholamine elevation) may also indirectly affect leptin levels in the brain. It is theorized that diethylpropion can raise levels of leptin which signal satiety. It is also theorized that increased levels of the catecholamines are partially responsible for halting another chemical messenger known as neuropeptide Y. This peptide initiates eating, decreases energy expenditure, and increases fat storage. It is used in the management of exogenous obesity as a short-term adjunct (a few weeks) in a regimen of weight reduction based on caloric restriction.

Cathine, known as D-norpseudoephedrine, is a psychoactive drug of amphetamine class, found naturally in Catha edulis (khat). It is a norepinephrine and dopamine releasing agent, and has thermogenic and anorectic effect. In the United States, cathine is classified as a Schedule IV controlled substance. Cathine hydrochloride is used as an appetite suppressant during the first few weeks of dieting to help establish new eating habits.