Sparkle is in the wrong place at the wrong time when she overhears Harvey’s plans to cancel her show – she’s in the men’s room at the aerobics studio because the women’s room is out of order. Their meeting takes place as Harvey head-on slurps down an endless supply of shrimp. Fargeat prefers close-ups of his chewing with his mouth open because she prefers to make even the most mundane activities look absolutely disgusting and repulsive.

This directorial instinct is a feature, not a bug. Fargeat makes films full of blood, guts and gore – and she wants you to see every drop of it. Her last film, the 2017 rape and revenge film Revenge, literally painted the walls of his apartment with blood. “The Substance” increases arterial spray by approximately 10,000 gallons.

But I’m getting ahead of the bloody story here. After being locked up, Sparkle gets into a serious fender bender. Not only does she return without a scratch, but she also comes back with a new idea, secretly presented to her by her ER nurse. Not only does his face look young, it also looks preternaturally smooth. As Sparkle soon finds out from the USB stick in her coat pocket, the nurse’s youthful appearance is thanks to The Substance.

What is the substance? It is a drug that creates a younger version of you from your own DNA. The new They’ll graphically fall off your back, complete with squishy sound effects. The two halves must spend alternating weeks in the real world; one is active while the other remains inactive. To stay alive, the active version must inject spinal fluid from the deactivated version into its body every day.

The seven day rotation is the non-negotiable part of using The Substance. The punishment for violating this principle is not nice.

“Remember, you are one!” says the creepy voice that operates the substance’s help hotline. The way he answered the phone made me laugh every time he called. And it’s often invoked because such strict rules are meant to be broken early and often.

After a brief bout of disbelief, Sparkle injects herself with the neon green goo she finds in locker 503 of an abandoned warehouse. This locker is constantly being filled with the items she needs to make this experiment work. Shortly after taking The Substance, Sue (Margaret Qualley) emerges from her back. Fargeat’s camera scrutinizes Sue’s feminine features so wildly that Russ Meyer looks like Walt Disney.

Immediately after stitching Elisabeth’s back (you can see every stitch in loving close-up), Sue heads to Harvey’s studio to audition for the new aerobics show. Of course she gets the job. Sue also becomes addicted to her newfound fame and repeatedly chooses to ignore the seven-day rotation rule. Poor Elisabeth is feeling the effects.

And what cruel consequences these are! You’ll need an Odie-strong stomach to get through “The Substance.” The last 20 minutes or so of this film – the best part – consists of non-stop blood and gore, mostly with the old-school practical effects that fans like me prefer. The delightful yuck factor made me forgive the film’s numerous problems.

Despite a very good performance from Moore, the makeup and effects departments led by Pierre-Olivier Persin, Bryan Jones, Pierre Procoudine-Gorsky and Jean Miel are the film’s MVPs. “The Substance” is only truly interesting when it fills the screen with images that make you gag and squirm. Luckily we get a lot of these images. Imagine the eternal youth-as-beauty horror-comedy Death Becomes Her, directed by Re-Animator helmer Stuart Gordon, and you’ll get a good idea of ​​what to expect here.

Although the film aims to be a scathing commentary on women and aging in Hollywood, there is very little substance to be found here. Qualley is as one-note as a silent movie villain, except she twerks instead of twirling her mustache. There’s more to Moore and it’s fun to see her return to her roots in the horror genre, but Elisabeth’s unexplored self-loathing existed long before she got older.

Plus, Moore looks amazing, so it’s hard to believe anyone would fire her because of her looks.

It’s not that The Substance hasn’t had time to explore its themes. The film lasts 140 minutes. If it had been 90 minutes, we could be talking about a classic. If there’s anything that “The Substance” desperately needs a shot at to reveal a leaner, tighter version of itself, it’s that film’s Cannes Award-winning script.

★★★

THE SUBSTANCE

Screenplay and direction: Coralie Fargeat. With Demi Moore, Margaret Qualley, Dennis Quaid. At AMC Boston Common, Landmark Kendall Square, Alamo Drafthouse Seaport, AMC Causeway, Suburbs. 140 min. R (lots of nudity, lots of blood)

This review has been updated with the names of the film’s F/X and makeup supervisors.

Odie Henderson is the film critic for the Boston Globe.