That's why I found it best to just keep upping my magnesium, then you are not going from one extreme to the other. Most laxatives can be a bit unpredictable (I don't know if it was you I told but syrup of figs is gentle and good for not doing that, for me anyway)
You can only get it online these days.
With the magnesium, I just keep track of how bad it is and take a bit more, maybe twice recommended, but usually one and a half dose works well.