What it does
SLS is such a reliable irritant that researchers use it as a positive control in skin irritation studies. That should tell you most of what you need to know about putting it on your face twice a day.
It is not dangerous — it is simply harsher than a facial cleanser needs to be, and it removes more of the skin barrier lipids than gentler surfactants do. The tight, squeaky feeling afterwards is not cleanliness, it is your barrier complaining.
Do not confuse it with sodium laureth sulfate (SLES), which is milder, or with cocamidopropyl betaine and the glucoside family, which are gentler still and clean perfectly well.
