Let’s imagine a day in the life of a legal-drug user. It begins with a wake-up energy drink. By midday, several cigarettes have calmed frazzled nerves before an appointment at the plastic surgeon’s office for wrinkle-smoothing Botox injections. A diet pill before dinner helps stem the appetite, and its stimulating effects can later be partially offset with a beer or two Advil PMs. And if performance needs enhancing, there are beta blockers for onstage performers, Viagra for middle-aged men, hormone-delivering “libido patches” for middle-aged women, and Adderall for students hoping to focus their concentration.