Question:
How long before protein breaks down?

I've heard that once protein powder is mixed, the protein only lasts for a short time before the protein is rendered useless. How long does it last? Also, how about the individual pre-mixed protein drinks such as Isopure glass bottles. How long does the protein last once the bottle is opened?    — y0maria (posted on December 30, 2003)

December 31, 2003
I'm not sure about the isopure in the bottles...but, thought someone had called the maker and they said like 24 hours or something. As far as mixes...I think the general consensus is that they start to lose effectiveness after about 1/2 hour. Hope that helps!
   — eaamc

January 1, 2004
I too was told 1/2 an hour before it starts to be useless...I however thought that was kinda odd. So I called the manufacturer of my protein, they told me 24 hours from the time it was mixed with any liquid, but it must be kept cold and mixed well after it has sat. Look on your lable and see if there is a phone #, call them and ask.
   — jennap