In my experience I felt a physical reaction to the grapefruit seed extract within 2 minutes. The caprylic acid and probiotic I took were both enteric-coated, but I felt a reaction to both of them within 10 minutes. As far as determining die-off, it's pretty unlikely you would react to all three of them unless you had candida. They shouldn't make you feel terrible, but if they do you can always stop them. I can't predict how you will react to them if at all, that's a risk you will have to take if you so choose. It sucks but it's the only way I know of to try to heal yourself.