I saw this movie in the 80’s I’m almost 100% sure I didn’t see it on TV. There was an alien in the form of a naked woman that was turning people into sand by (I think) kissing them. The protagonist defeats the alien (possibly) by stabbing her. The actress playing the alien looked a lot like Jennifer Connoley (to an 8 year old), but I’m sure she wasn’t doing those types of movies yet.
Sounds like Lifeforce (1985).
Bump