What an interesting question! I don’t know so much about make-up primer, but it is a clay-based formula, so I would imagine it could quite easily work as a mask. If you painted it on to your skin and allowed it to dry, theoretically, yes, it should absorb the oils and impurities and help for oil control. In my mind I would imagine it may be a bit drying to use as a make-up primer… however, if you’d like to try it, by all means go ahead. It certainly can’t cause you any harm.