"Botched" star Dr. Terry Dubrow is over the moon about Oprah opening up about using weight-loss medication ... 'cause, in his eyes, it's a move that could save lives.

Dr. Dubrow joined us Thursday on "TMZ Live," singing Oprah's praises for admitting she's used meds as part of her weight loss journey ... and telling us the trend of shaming folks for using medication like Ozempic needs to stop.

He says celebs have been hesitant to be as honest as Oprah was ... often attributing their weight loss to working out or hormones, but in the doc's eyes, it's time they felt comfortable to speak candidly.

Dr. Dubrow thinks a really popular celeb, like O, opening up the discussion could start a trend -- or at least a discussion -- that leads to the general public warming to the use of these meds to combat obesity.

As he points out, we wouldn't shame people who take insulin for diabetes ... so doing so for someone who needs it to lose weight is equally ridiculous.

As we reported, Oprah lost 40 lbs this year and told PEOPLE the medicine she was prescribed was a healthier alternative for her -- this after she realized her struggles with weight loss were less about willpower and more about the brain.