Finally, “The Substance” is very much a woman’s movie. The way writer-director Coralie Fargeat presents Demi Moore and Margaret Qualley — the matter-of-fact way in which she films their bodies, and the trust that she elicits from them — has the unmistakable stamp of a woman director. This is obvious within minutes.

The Substance” blowtorches a single idea for two hours and 20 minutes, and narratively it turns to ashes by minute 40. It’s easier for a movie to become a talking point that way. Film festival buzz, which “The Substance” enjoyed at its Cannes world premiere,

The actress stars alongside Margaret Qualley and Dennis Quaid in Coralie Fargeat’s gleefully grotesque movie about an aging celebrity who takes an experimental drug that gives her a younger self.