Two options exist once you land, and they are not the same. Keep the same clock time in the new zone, which compresses or stretches the gap between doses. Or keep your body's schedule, which means the dose fires at a new local time. This shows you both.
Time zone dose planner
Home time → local time
Your flight
Offsets are hours from UTC. London in summer is +1, New York is −4, Tokyo is +9.
| Dose at home | Keep local time | Keep your body's schedule |
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Deciding which column to follow
For most things, the middle column is fine — switch to local time and stop thinking about it. For a medication with a narrow window, the right column is the one that preserves what the prescription actually asked for, at the cost of an awkward local time for a few days.
Which of your medications belong in which column is a question for your pharmacist, and it takes about thirty seconds to ask. There is more on what breaks and why in medication reminder time zone changes, and the rest of the trip checklist is in travelling with medication.
Where the medication allows it, anchoring a dose to a meal rather than a clock time sidesteps the whole question — your meals shift with you. Doz supports meal-anchored doses for exactly this reason.
Common questions
Should my doses follow local time or my body?
It depends on the medication, and it is a medical question rather than a settings question. For a vitamin it does not matter. For anything on a strict interval it does. Ask your pharmacist which of your medications actually care, and only adjust those.
What is the risk of just switching to local time?
Flying east and keeping the same clock time shortens the gap between your last dose at home and your first dose abroad. Flying west lengthens it. For a medication with a narrow window, a gap that is several hours too short or too long is the thing to avoid.
Do meal-anchored doses need adjusting?
Much less. If a dose is tied to a meal rather than a clock time, it moves with your meals as your day shifts, which is usually what you want on a trip.
One thing this cannot do
This is an arithmetic tool, not medical advice. It works out dates and times from numbers you type in — it does not know your medication, your prescription, or what you should do if something goes wrong. Anything about changing a dose, spacing doses differently, or handling a missed dose is a question for your doctor or pharmacist.