If you have a good stopper and make sure you wipe it before and after with alcohol pad and use a new needle every single time you poke through, I have used the same vial for 6 months. I could have gone longer probably, but it ran out.

If it is a good rubber stopper, that in itself is supposed to reseal keeping bacteria out. I have used a vial over a year before. It is for sure good after 30days or longer

So.. there are two things going on here. A sealed vial of Test C (or fill in the blank) is good for quite a while, some people say 2-3 years, others say a lot longer.

The 30 day window you are talking about is using the vial within 30 days of breaking the seal. It’s not that Test turns bad or “expires”, it’s recommended to throw after that time due to bacteria entering the vial and compound. Like the said, the actual compound is still good for years but the microorganisms growing in said compound are not.

I’ve stretched out a vial after breaking seal to up to 60 days, never had a problem. I’m sure a lot has to do with if the compound is in oil, which type of oil, water, etc. I would imagine water based compounds are prone to bacteria a lot more than oil but that’s it my opinion.

hey Garrett, to answer your question, personally I wouldn't worry about using a vial 2-3 months after first use. It all depends on how you dose the vial and I sure as heck wouldn't bin a vial that still had a good amount of test left if I was running my cruise dose for example.