India, Oct. 31 -- A few days ago, a 45-year-old woman came to me seeking treatment for obesity. She was not diabetic, but was about 20 kilos overweight and could be a suitable candidate for medication. I began explaining tirzepatide (Mounjaro), including its benefits and potential side effects. She cut me short. "I don't want Mounjaro. I've heard a lot about its side effects."

I asked what she would prefer instead.

"Retatrutide. All my friends are taking it."

I asked whether she understood its potential risks and knew that it had not yet been approved for routine clinical use. She replied that she had learnt enough about it from Instagram and Reddit. Here was someone worried about the side effects of an established medicine, yet reques...