I bought 20 ampoules of hydroxo online and it has a use by date of 2019 on. Next time I'm thinking of getting 100 to save on the postage. I'm injecting about every two weeks, so at that rate, they would probably go over the date before I'd finished using them. Silly question maybe, but if I carried on using them past the date, would the quality be affected? Has anyone used them after the date on the pack and still been OK? Or would it be better to buy less but more often and just stump up the postage.