Daily Patterns in the Timing of Medication and Supplement Intake

Background/Objectives: The timing of medication intake can influence therapeutic efficacy and adverse effects, yet little is known about when medications are actually taken in daily life. We aimed to characterize real-world temporal patterns of medication and dietary supplement use at the population level. Methods: We analyzed time-stamped medication and dietary supplement records from 26,069 adults enrolled in the myCircadianClock smartphone application, generating a population-scale atlas of real-world intake timing. Results: Across more than 200,000 intake events, medication use exhibited daily patterns, with most therapeutic classes following one of two dominant patterns: morning- or evening-predominant intake. In contrast, dietary supplements displayed four distinct temporal patterns, largely corresponding to morning, meal-associated, or bedtime use. Medication timing was highly consistent across age and sex, although the types of medications consumed varied substantially with age. While the timing of many medications aligned with general chronotherapy recommendations, every therapeutic class exhibited considerable variability, with a substantial proportion of intake events occurring several hours outside the predominant intake window. Conclusions: This population-scale atlas provides the first comprehensive description of real-world medication and dietary supplement timing. These findings suggest that temporal adherence may be considered an important dimension of medication-taking behavior.