It’s not uncommon to find multivitamins or individual vitamin supplements that migrated to the back of the cabinet and are now past their expiration date. Although it may not be dangerous to take expired supplements, they won’t be as strong as when you first bought them. The FDA does not require that supplements have expiration dates, but most reputable vitamin companies will try to determine when the supplement loses its potency.
Potency
The main issue with taking vitamins after their expiration date is that they lose their potency and therefore their effectiveness. Generally, an expiration date indicates the last date of their highest level of potency. You are likely taking a vitamin to get some health benefits, so you want your vitamins to be as effectively potent as possible. If a label says it contains a certain amount of a vitamin, after a year or two there may only be half as much because it breaks down over time. It is difficult to quantify how much is degraded, therefore, its best to just throw away expired vitamins and supplements.
Side Effects
Expired vitamins do not go bad like food does and they do not turn into poison or toxins. Many expiration dates are set very conservatively because it benefits the supplement company. It is not dangerous to take expired vitamins, but as mentioned, the vitamins will lose their potency. There have been no documented cases of illness or death from expired vitamins, but throw the supplements away if they have an off smell or have changed color.
Proper Storage
If not stored properly, vitamins will lose their potency even faster. Exposure to heat, light, and air can cause vitamins to degrade faster. Store the vitamins in their original containers in a cool, dry place. Do not allow the vitamins to be exposed to heat or light. Many of the B-vitamins are very sensitive to light exposure. Some supplements require refrigeration or other special storage, so always follow the directions on the bottle.
Disposal of Vitamins
If your vitamins are expired and you want to toss them, get rid of them properly. It is important not to flush them in the toilet or throw them into the trash. Putting them into the water supply can possibly hurt other people and organisms. If an animal or child gets into the trash and accidentally consumes the vitamins, they could get sick. It is better to mix the vitamins with used coffee grounds or cat litter and then put that into a container with a lid.
http://healthyeating.sfgate.com/vitamins-expire-bad-7219.html
Will Hayes Fitness of Charlotte, NC 