Vitamins and other pills are allowed in your carry-on luggage. The vitamins need to go through the X-ray machine at security. An alternative option is to allow the screeners to inspect your vitamins and other medications. To avoid any problems, carry your vitamins in the original packaging so the screeners are able to see what it is.
Pack your vitamins separately from other items that might leak during travel, such as hairspray, cleanser or other liquid toiletries. For longer vacations, consider buying a small container of your over-the-counter vitamins once you arrive at your destination. This eliminates the risks present during air or car travel. If the vitamins are affected by hot, humid conditions at your destination, you won't lose your regular, large bottle of vitamins.