I have an opened bottle of Mag-10 that I can’t, for various reasons, start using for at least three weeks. Will the stuff still be OK 3-5 weeks after opening? Can I store it at room temperature or should I put it in the fridge?
You would probably be OK for the 3 week period but I think almost all open fluids should be refrigerated to be safe.
I have posted about this before, and the basic response from Bill R. was that a few weeks at room temp should be fine, but for prolonged periods (many months), refrigeration would be a good idea.
No it’s not ok…send it to me to my address : For the Handsome Bastard who can NOT order any prohormons because the FUC#%N custom regulations in his country 
Just kidding,put it in the fridge and enjoy it latter.