Products made under the above conditions, if stored properly in unopened bottles, should last at least two years before any loss of potency occurs, and, once opened, they should hold up for at least one year. Initial quality is paramount.
http://www.life-enhancement.com/magazine/article/1734-supplement-expiration-dates-how-reliable-are-they
Excluding certain prescription medicines such as nitroglycerin, insulin, and liquid antibiotics, most medicines stored under reasonable conditions retain at least 70% to 80% of their original potency for at least 1 to 2 years after the expiration date, even after the container has been opened.
http://www.consumermedsafety.org/safe-medicine-storage-and-disposal/what-does-a-medicine-s-expiration-date-mean
Actually, it's the date up until which the drug manufacturer can guarantee that the medicine is fully potent and safe to take based on product testing. Expiration dates are typically conservative to make sure you get what you paid for—a fully potent and safe medicine.
http://www.consumermedsafety.org/safe-medicine-storage-and-disposal/what-does-a-medicine-s-expiration-date-mean
MUFFIN, Oklahoma City A This is a commonly asked question, and the answer must be qualified. Regarding drugs, the FDA has monitored what they call the shelf life extension program (SLEP) of drugs for the past 20 years for the United States Department of Defense.
http://www.life-enhancement.com/magazine/article/1734-supplement-expiration-dates-how-reliable-are-they
Buy vitamins in small quantities so they stay fresh and potent. Check the expiration date on your vitamin supplements for the first indication of how long they'll last. Vitamin supplements typically bear an expiration date of a year or so from the time they're manufactured. If you store them properly, they should stay potent for at least this long. After the expiration date, you can still expect to use them without harm, but there's no guarantee on potency. Using vitamins that have passed their expiration date isn't likely to hurt you, but it might not help you much, either. Vitamins tend to lose their potency over time -- by as much as 20 percent to 40 percent. Some nutrients, such as folic acid and vitamin B-12, lose around 10 percent of their potency after six months, according to the United Natural Products Alliance.
http://healthyeating.sfgate.com/long-vitamin-supplements-last-bottle-11224.html
So, clean out your medicine supplies regularly, and replace any medicines that are more than a year or two beyond its expiration date. Reference: 1) Drugs past their expiration date. The Medical Letter on Drugs and Therapeutics. October 8, 2002;44(1142):93-94.
http://www.consumermedsafety.org/safe-medicine-storage-and-disposal/what-does-a-medicine-s-expiration-date-mean
Drug manufacturers are required to stamp an expiration date on their products. On over-the-counter (OTC) medicines, the expiration date is often printed on the label or carton under EXP (see photo) or stamped without ink into the bottom of a bottle, carton, or the crimp of a tube.
http://www.consumermedsafety.org/safe-medicine-storage-and-disposal/what-does-a-medicine-s-expiration-date-mean
Life Enhancement Products uses only vitamins manufactured by the successor company to Hoffmann-La Roche, as well as amino acids, hormones, herbs, and other supplements from the world’s premium producers. Lyon RC, Taylor JS, Porter DA, Prasanna HR, Hussain AS.
http://www.life-enhancement.com/magazine/article/1734-supplement-expiration-dates-how-reliable-are-they
For example, the vitamin C developed by Hoffmann-La Roche has been found to outlast other vitamin C products by many years (unopened samples have maintained their purity and potency for up to 20 years). Other vitamin C products have been found to darken, changing color from brown to gray to black in only a few years.
http://www.life-enhancement.com/magazine/article/1734-supplement-expiration-dates-how-reliable-are-they
(With all that testing, the cost of the SLEP study must have been staggering!) But we do know, from stress and stability studies of individual supplements, that there is a great deal of variability, just as there was in the SLEP study. The principal factor that determines shelf life is initial quality.
http://www.life-enhancement.com/magazine/article/1734-supplement-expiration-dates-how-reliable-are-they
how long after expiration date can vitamins be used?
The vitamins can be used for 1 to 2 years after the expiration date. After expiration date, vitamins can be used for 1 to 2 years.