"Senomyx's products work by amplifying the intensity of flavors. This is done by isolating human fetal kidney cells in order to enhance taste receptors. Because very small amounts of the additive are used (reportedly less than one part per million), Senomyx has no obligation to report their ingredients to the consumer. Senomyx products fall under the broad category of "artificial flavors." For the same reason, the company's chemicals have not undergone the FDA safety approval[citation needed]."