To be totally accurate, it is Ozempic (semaglutide) that has been around for 20 ish years, but only recently approved for weight loss. Mounjaro (tirzepatide) is newer and only been in use for 8 years or so. They are both the same kind of chemical with a similar action (GLP-1 agonist).
Mounjaro has been shown via research to be more effective for weight loss and has fewer side effects.
Both are safe, as with any regulated medicine, if used as directed by the prescribing doctor.
I've been taking it for 10 weeks now, started at just about 22 stone, and am now 18st 10lbs or so. It suppresses my appetite and makes me feel full quicker. I don't have any urge or interest in snacking or in high fat, high sugar or salty foods. The things I feel like eating are high protein, lots of fresh salad or veg. I eat three times a day, a lot smaller portions than I would ever have done before. I don't feel hungry or like I'm starving myself.
When going out for meals, I choose smaller things and eat less of them, I don't usually finish the kind of portion that most places serve. I still enjoy what I'm eating but just have a lot less, and leave what I can't eat.
I've had one instance of digestive upset, and I think it was caused by eating something dodgy but I had quite a large reaction which is unusual for me. Took a couple of days to settle down, but that was it. Other than that, I've not had anything side effect wise.