Is Insulin That Expires In A Month Still Good?

There are a lot of stories and anecdotes going around stating that expired insulin is still usable even though less potent. Some of these accounts even claim that expired insulin is still better than no insulin at all, which is wrong, and could be harmful for people who may believe it. Is insulin that expires in a month still good, yes, but any less than that and it may have reduced potency, none at all, or have adverse effects.

Credit image: Brian J Mantis

Problems Associated with Expired Insulin

While some expiration dates on medicines are very conservative, the risk is still too high and there is usually a very good and logical reason why those expiration dates were put there. Technically, some medicines should still have 90% of their potency a month before the expiration date, so insulin that expires in a month is still good enough for use. However, some medicines become toxic after the marked expiration date, which is why you can see some medicines expiring in years but some that expire in a matter of days.

Injectible insulin is less forgiving with expiration dates due to the issues of crystallization and degradation. Expiration dates are not pulled out of a hat and in the case of crystallization and degradation, disregarding said expiry dates could result not only in insulin’s loss of potency, but also in fatal harm, since degradants usually turn into toxic materials after expiring. (This applies to a large number of injectible medicines as well)

Even if the expired insulin is not toxic and has just lost a large part of its potency, it can still be harmful for diabetics specially those who are afflicted with type 1 diabetes mellitus. The type 1 case of diabetes happens to people whose body has become incapable of making insulin on its own. A type 1 diabetic who uses expired insulin will not receive his body’s required amount, and may trigger an attack of hypoglycemia.

Hypoglycemia is a serious health problem that is caused by too much sugar in the bloodstream for long periods of time. This affliction normally damages the vessels and organs that supply blood, and can lead to heart diseases, strokes, kidney diseases and visual problems as well as permanent brain damage. Hypoglycemia also has immediate effects that mimic an epilepsy attack both in severity and look, which can result in improper treatment if misdiagnosed.

There have been cases where insulin that expires in a month is still good enough for type 1 diabetics, in spite of the 10% reduction in potency, but I do not recommend risking a diabetic’s health just to prove something, when it would be much safer and practical to discard the expired or soon to be expired vials, and just buy a new one. Insulin may be relatively expensive these days, as with all things. But health has never been an aspect of life that benefits from being stingy – “you get what you pay for” applies perfectly when it comes to medicine and health. Saving on money does not necessarily equate to saving a person’s life.

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