Nikki Glaser is throwing major shade at the Ozempic critics ... saying they're just thin white women feeling threatened.

The comedienne didn't hold back on "The Tonight Show Starring Jimmy Fallon," saying she’s all for people using the weight-loss drug and wants them to feel comfortable talking about it -- despite the shame from thin folks who she says want you to stay fat.

Nikki gave more context, saying thin women are mad because being thin is all they’ve got -- while bigger people have had to work on their personality, and if they got skinny too, they'd be the total package.

She also calls out the people whining that Ozempic was originally developed to treat Type 2 diabetes ... saying they’ve never cared until now -- but suddenly they're upset diabetics can’t get their meds because everyone's using it for weight loss.

In true Nikki fashion, she wraps it up with a savage message to the Ozempic haters -- "You’re just upset that Kathy Bates has a thigh gap!"

Ozempic has become the ultimate Hollywood soap opera -- Oprah, Sharon Osbourne and others have been on the bandwagon, while Jillian Michaels, Kate Winslet and more are opposed to its widespread use.