OC, if you dig back through the archives, there are a few posts that touch on the notion of Shelf Life and Expiration Date as it applies to Lugol's and other commercial Iodine product. I remember reading several of these myself, one of them as recently as 2 days ago (I remember 'cause I contributed to a few of those threds). What you will find is that there has yet to be a hard and fast answer to the "shelf life?" question. There are some good reasons why it's difficult to provide a hard and fast answer for this. Chief among these will be that there are too many variables too difficult for the average do-it-yourself home product consumer to validate through their own efforts. You either trust the Expiration Date, ignore it, or try to find some happy middle ground.
I do not want to portray this as a clear conensus, but the general sentiment is that the Expiration Date likely to be affixed to a commercial but genuine Lugol's Solution product is kaka ..... means very little to the actual life of usefulness that product will provide you while it is on your shelf. To a large extent, such a date is put on products only as a matter of what passes for law these days. This kind of Expiration Date is more likely to have been fixed at whatever date it was for less than genuine reasons. I say this moreso as it pertains exclusively to true Lugol's Solution made from reasonably pure I2 / KI / water. If these ingredients were reasonbably pure to begin with, there is not much other stuff present to "break down" into other ingredients over time other thant the trace amounts of impurities that exist in all grades of purity. Compare this with products that are made from the get go contain various preservatives , additives, chemicals, what not. Granted, in the beginning of the shelf life, these additives may have been pure. Over time, the more variables (like - the more ingredients there are to start off with) the better the chances for these ingredients to oxidize and combine and continue to oxidise and or break down over time (hard to predict how much time) so that the product eventually becomes changed from it's origin due to slowly being diluted with whatever it is that it's breaking down into.
Going back to Lugol's, even the best ingredients will contain tiny amounts of impurity, and over time these may cause the collective product to gradually break down into containing harmful byproducts. Everybody tends to interpret "expiration date" and "born on" product labels a little differently. I know some people who have developed a pattern that one day a week, they walk through their house with a big garbage can, throwing into it any and all household products for which they find it is now a day or more beyond the date indicated on the label. On the other hand, I also know some people who literally never throw out anything, no matter what kind of commercial product it started out as - food, cleaner, medicine, beer, you name it. Again, we all will find our happy medium somewhere between these two.
Thanks much for this info Wombat. I agree about the unofficial shelf lives. I have a product from Lane Labs, "Skin Answer" that they can't sell anymore, that I bought 8 years ago. It is still working great. Color has changed and maybe potency; but it works for me.
I could not find shelf life for Lugol's; but this is interesting from a government site. It regards KI only, in tablet and liquid. Should be similar to Lugol's iodine/iodide. It seems that the tablets will last longer.
As with all drug products, the manufacturer must specify an expiration date of the drug on either the package or the individually wrapped tablet. The NRC distributes two tablet strengths of potassium iodide, 130 and 65 mg tablets. The shelf life of IOSAT 130 mg tablets is 7 years and the shelf life of ThyroSafe 65 mg tablets is 6 years.
For States interested in extending the shelf life of KI, the FDA has published guidance exit icon on shelf life extension for the tablet form of potassium iodide. Extending the shelf life of KI tablets is possible due to the inherent stability of the chemical form. However, the tablets must be stored under the conditions specified by the manufacturer to be considered for shelf life extension. In addition, this guidance only is intended for Federal agencies and State and local governments that maintain KI stockpiles under the conditions specified by the manufacturer.
The liquid formulation of KI also has a shelf-life of 5 years. The extension guidance does not apply to this product form."
I have a bottle of "Tincture of Iodine" that show and expiration date of July of 1983!! That's 24 years.
It still looks the same. Some of the alcohol may have evaporated every time I opened it and it is now down to about 1/5th of what it was. I added some Lugol's to it so the applicator could pick up more than a dot.
According to Mr. Les Shannon, VP of Clarkson Labs, "Do not let the solution get to cold or the Iodine could precipitate out. Lugols is very stable otherwise and it should be good for about 30 years." The lack of expiration dates on bottles is one sign of this. After much web-surfing, I found other indications that this is correct. The shelf-life issue seems to have been fabricated by those who want to limit us to purchasing small quantities at exorbitant prices. Considering the difficulty in preventing it from being diverted into meth manufacuting otherwise, I can see their point of view. If a one-ounce bottle will last about a year, so what if it costs $10 or so?