Oxygen degrades the flaxseed oil. That is why most bottles have some antioxidants in there to protect it from O2. Now when you shake the bottle, or put it in your shake, all you're doing is speeding up the process of degrading the flax. Just pour out a tablespoon and drink, that's the best way to take it. And keep refrigerated. Some supplement shops have caught on and keep flax refrigerated now, which is good thing.