You can add a view and add a filter to that view which filters requests which have domains of your choice in them. Add the domain(s) your site is hosted on and

You can add a view and add a filter to that view which filters requests which have domains of your choice in them. Add the domain(s) your site is hosted on and you'll get rid of most referrer spam; it seems like they call the GA API directly with your UA code, without providing a destination host. Caveat: the filter did not apply retroactively to my data and only started working from the date of its inception.