Probably less than you are afraid of. Big ships have stabilisers, and on a calm itinerary a lot of people genuinely never feel the ship move.
Two things reliably help if you are worried. Position: low and mid-ship moves least, because a ship pivots around its middle — the high decks and the pointy ends swing most. And horizon: being able to see it settles most people faster than anything else, so get outside rather than lying in a dark cabin cataloguing how you feel.
Where it does bite is rough water on exposed routes. A transatlantic in winter is a different proposition from a Caribbean loop, and nobody should book their first cruise on a crossing.
We are not going to recommend remedies — ask a pharmacist, they will ask you the right questions first. But if you have found something that works, this is the thread for it.
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