Mounjaro - how quickly did you notice its effect?

[Doobydolly]

Hello, I'm about to start taking Mounjaro tomorrow on the starter dose of 2.5mg, and wondered if any of you who have been taking it for a while can tell me how soon the effects kicked in. Given that a full dose is 10mg plus, I am dubious that such a small dose will do anything at all, given how large I am and how huge my appetite is. Would love to hear from you with any feedback! Thank you.

Thank you so much for your reply. I wasn’t sure whether you stoped using it at your goal weight or if it was normal to continue. Unfortunately there is a lot of negative press online so it’s hard to know what to believe.
it has never been an option not to loose weight. Once the consultant said it was needed I was 100% going to do it. The question mark is over if I get help or try to do it with just diet and exercise. It’s just nice to get the insight from people already going through it. Thanks again

@LottieAnne07 In your situation I would absolutely use medication to help you with the diet and exercise. Maintenance of weight lost is an issue regardless of how you get there, and using a weight loss medication will help you get there more effectively than doing it without treatment.

Because these medications are relatively new, what you do when you get to goal weight is not something that there’s clear guidance on yet. It’s also up to you as an individual as to how you think you’d manage if you stopped taking the medication immediately.

Don’t think of it as a quick fix.

It’s a tool to help you lose weight and works brilliantly, but also medication for obesity so without it, you’re likely to regain the lost weight unless you make drastic changes to your diet and exercise regime and improve your metabolism.

Most people with at least 5 stones to lose aim to stay on MJ for at least a year or two to maintain once they reach their target weight. I’ve lost 4 stones so far and still need to lose at least another 1.5 stones and I expect to stay on a low dose for the next couple of years to help re-set my body’s ability to metabolise food more efficiently.

I noticed it within the first week on 2.5mg 🙂 I was sceptical at first, but it really helped quiet the constant hunger and made it easier to eat less without feeling awful. I’m on a medically supervised programme too, which made me feel much safer starting, and it’s been more affordable than I expected as well 😅

I noticed it in the first week even on 2.5mg, mainly just less food noise and getting full a lot quicker 😅 I’m doing it through a medically supervised programme with regular check-ins, which really helped me feel safer starting. It’s actually been more affordable than I expected too 🙂

Hi Brenda. I've gone back on Mounjaro last Friday. I started it in May 2025 & lost 3 & half stone by November but had to stop it for Gynae surgery plus although I was fine on 2.5 going up to the 5mg gave me stomach pains which after an Endoscopy was found to be Gastritis. This time my GP has advised I stay on 2.5. I can't get it through the NHS because even though my BMI is over 40 & I have Osteoarthritis in both knees I still don't need the criteria for NHS. So, aged 72 I'm paying £189 monthly. I'm a bit concerned because this time around I don't seem to have had any side effects & not lost a pound & not sure I'm feeling less hungry. I'm drinking more water this time as I don't want Gastritis again I'm also trying to keep my protein up. But, nothing seems to have changed. My starting weight last May was around 22 stone, after losing all I did & stopping last November I put a stone back on from January 2026. I just hope Mounjaro works again for me this time around because I don't feel it is. Maybe, I'm too old now. Good luck with it all Brenda. xxx

I felt the same before starting Mounjaro, I didn’t think the lowest dose would do much. For me it wasn’t instant, it was more gradual over time. I use the programme support for check-ins, but honestly it’s been more about learning simple routines and not overthinking food day to day.

MJ effect instant
second week wore off at day 5
third week wore off at day 3
every dose up instant effect first week (8-12 weeks before upping dose, 7 months 4st loss 5st total)

second round (7 week break after cold turkey at 12.5) no effect but a similar effect to week 3-4 first 1-2 weeks of upping doses (now on 10 about to start 12.5)

looks and feels

first to shift was underwear 22-18 at about 15kg loss
bra at about 15-20 kg loss (2 cup sizes and 3 strap sixes, still at this size now despite another 5-10 kg loss )
clothes 20 kg down and 4 sizes down (in denial due to the brain not catching up)

now in denial of being size 18 but reality 14-16 (down from 22-24 / 25-30 kg/4-5st) and about to shift into the new size (when I allow myself that and accepting that I’m a smaller size)

I felt the same before starting Mounjaro, I didn’t think the lowest dose would do much. For me it wasn’t instant, it was more gradual over time. I use the programme support for check-ins, but honestly it’s been more about learning simple routines and not overthinking food day to day.