In light of circadian research, prescriptions like “Take Once Daily” are terrifyingly vague, reports The Atlantic.

The idea is that biological rhythms, daily oscillations in physiological processes, make the morning body a functionally different creature from the same body at night. There are peak times of day for each organ’s cell division and metabolism, as well as core temperature and gene expression. Moreover, our illnesses are rhythmic, and our pathogens have body clocks. It makes for a major strategic advantage over disease, and the current resistance in the medical field—a misconception that timing effects are somehow minor—is no longer tenable.