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So I have 2 bottles of Dusta but I looked at my last order and just realized they are (2) years old. Company I ordered from claims that they are good for at least one year if stored properly.
They have been stored in my dresser drawer in a cool dark environment.
What do you guys think? Loss of potency? To much time? Or still usable?
Thanks!
Old post I'm aware, but here goes.
The VAST majority of stable substances do not lose very much potency with age. There are exceptions for some things like vitamin C, that truly does degrade in a year. But almost everything has either a very, very short life(weeks to months), or nearly unlimited.
Pharmaceutical shelf life is determined by estimating how long a product will remain at 95% potency. So if a product has a shelf life of "1 year" it means it loses about 5% potency in the first year.
While many products have decelerated rate of potency loss, almost nothing has an accelerated rate of loss. So if something has a shelf life of "1 year" it losses no more than 5% potency per year.
I had some benzole peroxide that was 15 years old. It has a shelf life of "6 months". Meaning it should lose 5% potency in the first six months. Well, obviously it can't have -50% strength, but surely it could be inert, right?
It could have. But it seemed to work almost identically to my fresh tube. If it lost potency I don't think it could have been more than 1/4. And that was 30x it's listed shelf life.