It turns out, putting the two dudes who scripted “The Hangover” (and “Bad Moms”) in charge of writing and directing a midlife crisis moms at a spa farce wasn’t the smartest move ever.

“Spa Weekend” — a title as colorless as the product — is a laugh-free farce of the “Girls Trip,” “Bridesmaids,” “Joy Ride” variety. Only old and moldy.

Think of it as a passing of the torch, from the Goldie, Lily, Jane, Rita or Jada generation to new “funny women of a certain age,” and you still won’t have lowered your expectations enough.

It’s meant as a break-the-rules/cut loose farce of the “Bad Moms” school — only funnier. Or funny. It doesn’t work. Ever.

Mid-50s Leslie Mann is birthday gal Jane, one of the four tween moms, “friends since middle school,” who do a girls’ get-away at the Solstice Spa up the California coast from their busy busy lives. She’s a lawyer, no longer married and lovelorn.

“The tough one,” Coco (Michelle Buteau) is newly divorced and ignoring her anger management issues as she shares custody and mocks her husband for taking up with an older woman.

Sophie (Anna Faris, at her least amusing) is still married, trying to hang onto a job as gopher/assistant to a hapless rich brat who can’t bear to run out of Cheetos when she’s out of town.

And Mel, “the crazy one,” the one most of them agree to not invite, is played by just-turned-50 Isla Fisher at her most Aussie and over-the-top. She’s just the one to fix up Jane up with the “manotantric” yoga instructor (Peter Thurnwald) at the spa.

“She’s on the ‘older’ side, but she’s got a porno body!”

That’s the comic level of the dialogue, here. The bar is so low on the physical comedy that pretty much any “accident” or pratfall carries the success or failure of the movie with it.

Erika Heynatz doesn’t do much with the role of spa guru/owner, a role that could have been a comic highlight in more skilled hands. Kathryn Hahn wasn’t available?

Actresses who clear 50 have few choices, and it’s almost too much to hope that a “First Wives Club” or “Something’s Gotta Give” or anything with a little dignity and message to it will be there when that AARP card arrives in the mail. It’s not out of order to try a little late career “raunchy” and lewd. But if it isn’t funny, limited choices or not, you should know better.

Faris and Fisher know funny. Mann? Well, she’s married to Judd Apatow. She, more than anybody, should know better and beg for a little script doctoring.

It’d be mean to point out who is battling Mother Time the hardest, or to name who is suffering from “Sandra Bullock Face” owing to fillers. Because that’s beside the point.

Let’s put the blame for this fiasco where it lies and repeat that old Hollywood maxim that applies –and how.

“Old guys (behind the camera) can’t do comedy.”

Rating: R, pot use, suggested sex, profanity

Cast: Leslie Mann, Anna Faris, Michelle Buteau, Peter Thurnwald, Erika Heynatz and Isla Fisher

Credits: Scripted and directed by Jon Lucas and Scott Moore. A Black Bear release.

Running time: 1:37