So you need .6% acetic acid if you want to prolong it life and not have to keep it in the fridge.
You will see 6% all over the place but you need to dilute to .6% using distilled water, the 6% acetic acid, and a whatman filter with a sterile vial. You take 10 parts distilled water to 1 part 6% acetic acid into a syringe, then twist on a whatman filter to the syringe and put a pin on the end of the filter (this is how it comes standard) and inject into a new sterile vial.
Having said that you can store IGF with Bac Water for a few weeks up to a month if its kept refrigerated.
Ive done this and it works. If you go the acetic acid route you also can dilute it by drawing up your IGF dose based on the amount of acetic acid you mixed it with then draw in some bac water to dilute and make the PIP less.