Last night I had the chills from the injection. It had been a while since that had happened so it make me wonder if had something to do with getting a little off schedule. The duration of the chills was less than normal or I was able to sleep through most of it. Of course where there are chills the hot flashes come in the morning and there was no disappointment this time. While I was drenched it lasted the average amount of time of about an hour. On a plus side the injection went very well last night.