Sam Asghari dropped several dozen pounds following his split from Britney Spears ... and while lots of folks in Hollywood are using meds to shed weight, Sam's not hopping on that trend.

We got Britney's ex leaving Equinox gym, and our photog asked him about his dramatic weight loss and his secret to losing 35 to 40 pounds.

Sam says his body transformation is NOT the result of Ozempic ... a prescription diabetes medication that's becoming widely popular among celebs and average folks as a diet drug.

Even Oprah recently admitted she's using meds to lose and maintain weight, and she refuses to be shamed about it.

But, Sam says he's been putting in work at the gym and watching what he eats -- telling us fitness often comes down to diet.

Sam's always been fit, but now he looks more toned and cut than ever and he says being in shape's always been a priority for him ... which is evident to anyone with eyes.

He's also got some tips for anyone looking to lose a few pounds -- in his eyes you don't have to resort to meds as long as you keep your hands out of the cookie jar.