I looked all over the bottle and couldn't find one. I did noticed there is a white crusty buildup around the cap though. They also changed the design of the bottle since I bought it..which definitely shows the age of my bottle lol! I tried doing a quick Google search and didn't find an answer, I was wondering if one of the other members knew or asked Dr. Tim which I know at least back in the day he would respond to emails about his products.mattgirl said:I wouldn't think so as long as it was sealed up. Is there a best by date on the bottle? If not then I have to think it is good until all used.