Fat-soluble vs water-soluble
Fat-soluble vitamins — A, D, E, and K — are absorbed better alongside some dietary fat, so a meal is the natural anchor for them. Water-soluble vitamins like B and C are more flexible and can be taken with or without food.
Many people find B vitamins suit the morning, since they are tied to energy metabolism, while magnesium is often taken in the evening. None of this is strict, so use it as a loose guide.
One routine that ties it together
Rather than memorizing a timetable, it is easier to group what you take together and set a reminder. Pillog lets you schedule each dose, check it off from the notification, and see your month as a card, all stored on your phone with no account and no ads.
If you take several supplements, a pharmacist can help you group them sensibly and flag any worth spacing apart.