You may buy of bottle of vitamins or minerals, take them for a few weeks and then stop. They may stay in your medicine cabinet for a few years without you thinking about the expiration date -- until you decide to start taking the supplement again. While you may think twice about taking zinc that's past its expiration date, taking expired minerals won't hurt you.
Food and Drug Administration Regulations
The United States Food and Drug Administration does not require manufacturers to put expiration dates on their vitamins and minerals. Manufacturers do this voluntarily, possibly so that you'll buy a new bottle of zinc because your old one has expired or to ensure that you get the full potency of the supplement, since theoretically your zinc could lose potency after its expiration date. Expiration dates indicate the date that the manufacturer can guarantee full effectiveness and safety as determined by how long it tested the product, according to the Harvard Medical School Family Health Guide -- not how long the drug actually is safe and effective.
Minerals and Stability
Minerals generally do not oxidize or degrade as long as you store them properly, and zinc falls into the mineral category. Minerals will last almost forever, Margaret Woltjer, Ph.D., reports on the Healthy Alternative Solutions website. Store zinc in a cool, dark and dry location.
Length of Time
The military, loath to throw out medications that have expired, conducted tests on the efficacy of prescription and over-the-counter medications after expiration. The tests found that of the 100 drugs tested, 90 percent were still safe and effective to use 15 years after they expired, the Harvard Medical School Family Health Guide reports.
If you need a prescription medication to treat a health condition, don't take expired drugs, since they could lose potency over time and might not adequately treat your medical condition. Zinc supplements generally are not essential for your health. While expired supplements could lose potency, they won't have any harmful effects if you take them. Medical authorities state expired drugs are safe to take, even years after their expiration dates, the Harvard Medical School Family Health Guide reports.