All drugs and vitamins start to age or break down the day after they are manufactured. Most all products are safe to take up to 1 year after expiration date. The concern is that the product may be less effective, the dosage may vary. Not all substances deteriorate at the same speed. For example: Vitamin A deteriorates one third faster then other vitamins. Quality vitamin manufacturers will beef up their vitamin A slightly to cover the time period that this vitamin may be on their shelf, distributors shelf, retailers shelf or in your home. A quality manufacturer will be sure their vitamins are approximately at the listed strength on the label at time of expiration.