This is a few ideas, but they all would work together.

Some medications are designed to be slow release, and they tend to give an average duration of efficacy. However, there are many factors which affect this duration meaning for some people their medication could last up to 14 hours before they wear off and for others it could be as little as 10 hours.

1 - It would be really useful if we could mark when the medication has worn off, as a time stamp with the original medication taken entry so that over time we can find our own, personal, average duration.

2 - It would be extremely helpful if this personal average duration could be part of the weekly reporting too.

3 - I know people have already mentioned time-stamping symptoms - this would also be useful in this use case because then if we forget to log the ‘end’ of the medications usefulness, seeing the time when the symptoms reappear could help us fill in that duration on a later date based on the symptom time-stamp.

4 - Same goes for hunger, actually - also mentioned in another suggestion, but also helpful for correlating with symptoms and medication efficacy.

5 - Finally, I think this may also have been mentioned as a separate suggestion, but perhaps having a notification / pop-up asking whether our medication is wearing off when we enter a symptom and it’s been at least x hours (customisable) since our last dose. (example, I set up the notification with a minimum of 8 hours after taking the dose, then 9 hours after taking meds I mark the ‘fatigue’ symptom so a pop-up appears saying ‘you took this medication x hours ago, could it be wearing off now?’)