If you read any review of The Substance, you expect this movie will Speak To The Issues of “beauty standards”, “fear of aging”, “the male gaze”, und so weiter. This is cheap. What is interesting about The Substance is that simultaneously, in this film men functionally do not exist. It passes at least two levels of inverted Bechdel test. Two men never talk to each other except about a woman. In fact two men never talk to each other - there is a brief scene where one speaks, thinking out loud (about a woman, at that) while another is present, and that is it.
In fact this might be the only film that explores autogynophelia from the perspective of a woman - that is, a real, non-pharmaceutical woman deriving enjoyment from her experience as a youngerhottertighter version of herself, without necessary recourse to any external observer at all. In the same way that men lift ultimately for themselves (you’re looking yuge today, king), in this film a woman’s beauty is fundamentally about reinforcing her internal self-image and defining her external status objectively, rather than putting on a display for anyone in particular.
This might seem paradoxical when the setting is some vapid exercise TV show. We have lovely, meta shots of camera lenses as they in turn take in shots of the best asses you will ever see. We even have a producer, Dennis Quaid, evaluating, yes, Margaret Qualley / Sue has “it”, and Demi Moore / Elisabeth is no longer ban(k)(g)able enough for TV. But no one is trying to appeal to him - he merely judges, correctly, one’s objective appeal, which is first and primarily perceived and enjoyed by the possessor. You are not buying off the teller at the bank - he’s just the messenger noting that you had the money, and you enjoy it first, Scrooge McDuck style, by personal experience, even absent any spending. Big line go up.
(Incidentally these camera shots are described by some reviewers as “pornographic” - you will never find porn with this much thirsty contemplation of bodies in motion. It’s erotic, for sure, but the eroticism is because it displays the beauty of a really, really nice ass, pair of lips etc, rather than a vulgar display of sexuality-as-such. The beauty generates sexual appeal as a side effect, but there is ironically nearly no “sexuality” in the sense of a man and a woman advancing on each other portrayed in the film.)
The premise of the film is that the titular Substance splits off a youngerhottertighter “version of one’s self”, with the proviso that you must alternate weeks of consciousness with them. (You can see where this is going.) The setup here is interesting - the anonymous purveyor of The Substance insists repeatedly “there is no ‘she’ and ‘you’, you are one”. This is… not true. There is no continuity of consciousness. Even identical twins are not “one” in some metaphysical sense, let alone a fissioned product of yourself.
What this seems to be is a metaphor for society, maaan. Specifically, the society of women, and the relationship between younger and older. “Respect the balance”, the purveyor insists. Of course obviously a movie needs to happen and something needs to go wrong, so Sue starts slurping more and more life-force from Elisabeth in order to, literally, enjoy herself, that is, her experience of being young and attractive, and Elisabeth passive-aggressively binge eats and leaves the apartment a shithole. Plenty of people live in shitty apartments without near murdering their relatives, so it's pretty clear who ends up taking more in this negative-sum game.
Ironically, a man with a properly working Outlook calendar would have fixed this. And in fact, Dennis Quaid’s producer character is all to happy to accommodate Sue’s week-on week-off schedule, although he doesn’t know the true reason. But there is no archetypal “Dad” enforcing actual respect between de facto mother and daughter. Instead, left to their own devices, they prey upon each other - first the old by attempting to vicariously live through the young, with minimal respect for their independent identity, and then the young by exploiting the old until it’s time to secret away hideous haggish Grandma in a closet.
There is a resolution of this, but it devolves into a monster movie and is not ultimately satisfying in resolving these tensions. I guess they could have… followed the rules? What’s the fun in that?! We’re doing the cover of Vogue on Tuesday!