Luxuriant eyelashes are considered to be highly attractive by most cultures – kohl has been used since the Bronze Age to protect and enhance lashes. More recently, mascara and eyelash extensions have become almost universal beauty aids. Now Allergan has announced that the US Food and Drug Administration (FDA) has approved the use of Latisse™ to enhance eyelashes. Bimatoprost, the active ingredient of Latisse™ was first approved in 2001 to lower intraocular pressure in people with chronic glaucoma or ocular hypertension. Patients treated with bimatoprost experienced eyelash growth as a side effect of the treatment. Bimatoprost is a prostaglandin analogue which is believed to bind to prostaglandin receptors in the dermal papilla and outer root sheath of the eyelash. Although the precise mechanism of action is unknown, prostaglandin receptors are thought to play a role in the development and regrowth of the hair follicle by increasing the percentage of hairs in the anagen (active growth) phase, as well as increasing the duration of the anagen phase. Following daily application of Latisse™, users can expect longer, fuller and darker eyelashes in as little as eight weeks, with full results in sixteen weeks. To maintain the effect, application must be continued – if discontinued the eyelashes will gradually return to pre-treatment appearance over a period of weeks to months (the average length of the eyelash hair cycle).