I think there are lots of people on it. A best friend of mine says tonnes are taking it - she's been on it for 1 few months. We live in an affluent middle-class area and the general impression is that people are definitely on it. Not openly. Of course the naturally slim people advise against it - with their fake concern - because they want to maintain the monopoly on being slim!
I asked the nurse about it during my smear test, as she told me I was at higher risk of breast cancer, being obese, and she said loads are on it, including quite a few of the GPs at my large surgery, and some of the nurses.
I think while there are people judging the use of it, people like me will remain quiet about it. I will only share it with others if I suffer side effects that make it harder to keep it quiet.
I am on it secretly - my DH, my best friend and my boss know. And that is it. My teenage DDs don't know, no other family at all, and no one at my sports club.
Funnily enough - I saw a fellow player at my sports training this week and she had noticeably lost a tonne of weight. She is tall and broad like me and her clothes were loose. I had just started MJ but it didn't enter my mind at the time when I saw her. I said "hey skinny-minny - you look fab, you've lost loads of weight" (I know her well enough to say this!). She said in a very non-committal way "ahh well, you do what you can" or something like that, and shut it down. In retrospect I'd be surprised if she's not on it! But that's her business. I'm not telling anyone so I don't expect her to mention it.