I usually notice a touch of improvement that night.. but it isn't until day 4 (after a one day treatment) that It really hits me dramatically and helps.. now if I get a loading dose the IVIG itself is hard on my body it seems.. so it took a bit longer.. the first treatment I had (4 days of it)... i was better, but thought maybe it was placebo effect.. it wasn't until the next treatment 3 weeks later that it was like BOOM _ I woke up my old self... I haven't gotten back to that good in a few years.. but it was amazing.. so sometimes it can take a bit... Good luck!!