The time it takes for tart cherry supplements to work can vary significantly from person to person and depends on several factors. These factors include the individual's overall health, the specific health condition being targeted, the dosage and form of the tart cherry supplement, and how consistently the supplement is taken. For some individuals, the effects of tart cherry supplements may be noticeable relatively quickly, within a few days to a week. However, for others, it may take longer, possibly several weeks or even months, to experience the desired effects.