About Vitamin Expiration Dates

From The New York Times:

Vitamins and dietary supplements are not required to carry expiration dates on their labels. ....

If companies want to print a “use by” or “best by” date on their supplement labels, they can do so voluntarily. But they are then required to honor those claims, said Tod Cooperman, the president of ConsumerLab.com, a popular independent testing company.

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The vast majority of ingredients in supplements decompose gradually over time, which makes them less potent, but not necessarily unsafe — unless, for example, they happen to grow mold. ....

If stored away from heat, light and humidity, supplements generally last about two years after the date of manufacture before the concentrations fall below 100 percent of the amounts listed on the label. But the window is only about a year for probiotics, liquids and oils, which are more fragile.

“If a probiotic label suggests refrigeration, do so,” Dr. Cooperman said. “Then return the bottle quickly back to the refrigerator before moisture gets in, as this will activate the organisms, causing them to briefly live and then die.”