Expired products won’t become toxic, but they’ll gradually lose potency beyond the best used by date. Probiotics, fatty acids and liquids should be used as soon as possible after the best used date since they’re more vulnerable to loss of potency. Most supplements in pill or powder form can be used for another year past the best by date. Minerals, which are very stable, could even be used for two years past the best by date. We don’t have research documentation on the rate of potency loss beyond the best by date.