Hi Melissa! Once you dilute the tincture with water & honey, it has a lower level of preservation (alcohol percentage) than straight tincture does. I’ve used propolis tincture in a lotion and sadly it got moldy within a month or so, so it’s a lot less effective when diluted. However, there’s a good chance these throat sprays (at least the tincture based ones) last longer than a few weeks, but I like to play it on the safe side and try to use them up by that time. :)