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Weight loss injections/treatments

Discuss weight-loss injections and treatments, including personal experiences. Mumsnet hasn't checked the qualifications of anyone posting here. You may wish to speak to a medical professional before starting any treatments.

Mounjaro - Has anyone ever become ill from Mounjaro or had any bad side effects?

22 replies

Biosblbay · 07/05/2026 10:35

I am currently 14 stone 6, a size 14 BMI 38 and would love to get back to 11 stone being a size 10-12 which is what I was before having my two children. I do join gym but I just don’t have the time working a full time job and having 2 children under the age of 3. I am considering mounjaro but I have quite bad health anxiety so I would be so worried taking mounjaro, hence this post to find out how people have found it, if they would recommend or if they wouldn’t.

I have spoken to many people that have taken Mounjaro, and the worst side effect I heard was severe diarrhoea, but other than that most people have been fine.

Please tell me your stories to help me make a final decision. Thank you! X

OP posts:
TheBroonOneAndTheWhiteOne · 07/05/2026 10:40

I've been on it for 28 months and I'm nearly at my goal now.
I've lost 9st 12lb.

I've had very few side-effects. Just very occasional nausea and a bit of heartburn and that was very much at the beginning.
I just took dimenhydrinate and Gaviscon if I needed to.

Foodieforsure · 07/05/2026 10:41

Lost 3.5 stone but ended up in hospital as I was so ill with sickness, I couldn't eat for a week and swallowing my saliva made me throw up. The side effects were always there when taking it, but after the hospital admission I knew I had to come off it.

RoseField1 · 07/05/2026 10:43

If you ask this question you'll get people saying yes. What you won't get is people who didn't get any significant side effects, and there are many more of us than those who did. Nobody can make your decision for you; is it worth the risk of side effects to lose weight and be healthy? Only you know this.

Branleuse · 07/05/2026 10:46

I've been on it a year now.
When I first started taking it I was super thirsty and had to drink loads.
I think it can make me a bit tired and I had a few gastric side effects in the beginning, but I've found side effects to be manageable and worth it.
I am quite sensitive to medication so I thought it would be worse. It's only a weekly injection too, so if you do get any side effects, they will usually be over in a few days even in the beginning

Clefable · 07/05/2026 10:50

Just remember when weighing things up that at 38 BMI, you are already putting severe pressure on your body and organs. Just because the damage may not be visible yet doesn’t mean it isn’t happening. What people often fail to think about when talking about the side effects of jabs is that the side effects of long-term obesity are often much more widespread and dangerous.

WeepingInASunlitRoom · 07/05/2026 10:53

D+V with sulphur burps (disgusting!). I've been on it for almost two years. Lost five stone in one year and it's taken me nearly another year to lose one more stone. I still have a stone to go to get to top end of healthy weight.

Because of the side effects, I keep my dose low which is why the second year's loss has been so very slow. I increase gradually, and made it to 7.5mg but after a few weeks on that, the D+V came back and as I had to travel for work and present to hundreds of people, I came off altogether for a week and restarted at 2.5mg. I put five pounds back on! So have just painstakingly lost that again as I build back up to 5mg where I will probably accept I am at my limit. I just seem to be very prone to the gastro effects and it's so unpleasant not to mention inconvenient. Pepto-bismol really helps especially with sulphur burps.

I expect to be on GLP-1s forever, so I don't mind taking it slow. To be six stone down in two years is life changing and amazing for my health. I just have to keep my dosage in the sweet spot of still losing but not suffering side effects.

Also, I know there are users who absolutely insist you only get gastro side effects if you eat the wrong things, but that's not always the case - it certainly isn't for me. It's a reaction to the medication when it reaches a particular level in my body, not an inability to tolerate certain types of food. I follow all the advice when it comes to what I eat. Other medications can cause nausea/d+v too - sometimes it simply is how a person's body reacts.

KojaksLollipop · 07/05/2026 10:55

Explosive diarrhoea and sulphur burps, occasional vomiting. I had to come off the injections as it never stopped.

Stillstanding54 · 07/05/2026 13:14

Successfully lost over 4 stone last year using Mounjaro. I came off in September and have managed to keep it off until the last month or so when the food noise has become uncontrollable and I felt the weight starting to creep back on. Only 5lb/6lb but enough to worry me
When I reached my goal weight and perfect BMI my prescriber told me that if, at any time, I was worried about loosing control I could go back on 2.5mg for a month or two, just to reboot and keep everything under control. I was very anxious about regaining.

So I contacted him and yes, he agreed I could go back on MJ for a very short period of time
I’m still well within my healthy bmi and am not overweight but anxious about piling it back on.
So the first week on 2.5mg was absolutely fine, felt back in control, eating healthily and a couple of pounds off
Second week, on the third day, my goodness, the nausea and vomiting. I couldn’t function and had to go to bed with a bucket. Luckily this only lasted 36hours or so
Third jab is due today and I’m worried about awful side effects again.

Could I reduce the dose by half, say? Would this reduce any potential sickness?

Would I still feel some suppression on less than the full 2.5mg
I don’t want to waste the remaining doses but cannot face being so ill again.
When I originally went on MJ I sailed through without any horrible side effects but I was obese then. I wonder if the drug has stronger results and effects on a much slimmer body?
Any thoughts and advice from more experienced people much appreciated

WeepingInASunlitRoom · 07/05/2026 18:58

Stillstanding54 · 07/05/2026 13:14

Successfully lost over 4 stone last year using Mounjaro. I came off in September and have managed to keep it off until the last month or so when the food noise has become uncontrollable and I felt the weight starting to creep back on. Only 5lb/6lb but enough to worry me
When I reached my goal weight and perfect BMI my prescriber told me that if, at any time, I was worried about loosing control I could go back on 2.5mg for a month or two, just to reboot and keep everything under control. I was very anxious about regaining.

So I contacted him and yes, he agreed I could go back on MJ for a very short period of time
I’m still well within my healthy bmi and am not overweight but anxious about piling it back on.
So the first week on 2.5mg was absolutely fine, felt back in control, eating healthily and a couple of pounds off
Second week, on the third day, my goodness, the nausea and vomiting. I couldn’t function and had to go to bed with a bucket. Luckily this only lasted 36hours or so
Third jab is due today and I’m worried about awful side effects again.

Could I reduce the dose by half, say? Would this reduce any potential sickness?

Would I still feel some suppression on less than the full 2.5mg
I don’t want to waste the remaining doses but cannot face being so ill again.
When I originally went on MJ I sailed through without any horrible side effects but I was obese then. I wonder if the drug has stronger results and effects on a much slimmer body?
Any thoughts and advice from more experienced people much appreciated

When I have had bad side effects, I have reduced the dose. In your situation, I would do a half dose and have pepto-bismol on hand - take it at the first hint of a sulphur burp and you can probably avoid the d+v. I have wondered if the reason I find myself unable to tolerate doses I have previously is because of my slimmer body but I don't know if that is possible.

Sallycinnamum · 07/05/2026 19:06

OP, I am at goal weight after taking it for a year and am now micro dosing 2.5mg.

I didn't have any actual vomiting but for the first few months I had mild nausea and when I increased the dose I felt completely wiped out and had to spend the weekend in bed. I never went further than 3.67mg for this reason!

That said, I now have minimal side effects unless I eat anything too spicy or rich.

Honestly just go for it. You can always stop if the side effects are too much.

Kitt1 · 07/05/2026 20:27

OP I think there’s something wrong with your figures. If you’re a size 10/12 at 11 stones, presumably you’d be around a size 14 at 12 stones, not at almost 15 stones. Plus with a high BMI of morbidly obese. You can’t be morbidly obese and a size 14 surely?

I’m short and started at 15st with a BMI of 39 but I was wearing size 20/22.

Safarisagoody · 07/05/2026 20:30

No negative side effects at all, the opposite, feel amazing, been on about two and a half years, maintaining for about a year and a half, size 8 down from a 18. All health issues I had due to weight all gone, blood tests optimal, sleep apnea gone, blood pressure not healthy, off the meds for that.

you just need ti do it right, three litres of water a day, eat a clean and healthy diet, ensure you consume enough protein, work out.

Safarisagoody · 07/05/2026 20:32

Kitt1 · 07/05/2026 20:27

OP I think there’s something wrong with your figures. If you’re a size 10/12 at 11 stones, presumably you’d be around a size 14 at 12 stones, not at almost 15 stones. Plus with a high BMI of morbidly obese. You can’t be morbidly obese and a size 14 surely?

I’m short and started at 15st with a BMI of 39 but I was wearing size 20/22.

I’d assume she’s very short, but I guess she knows her dress size.

LoveYouPickle · 08/05/2026 08:36

I have had a few episodes of vomiting, upset stomach etc. however I'm a sick bucket anyway so I think if you are prone to sickness you might be more susceptible? I don't know 😂 I'm the only one in the house who is ever sick even before mounjaro!

Ineedanewsofa · 08/05/2026 08:50

I had quite bad constipation about 3 months in which took me a while to work out what was causing it - I was taking too many supplements with caking agent in and because MJ slowed my gut down they were caking up my bowel! Stopped taking them and everything returned to normal.
Nothing else significant, the odd queasy moment and a bit of a headache on jab day but that’s it. The benefits far outweigh any side effects for me, I’m 4 stone down, a healthy BMI the fittest I’ve ever been and have zero joint pain any more.
An acquaintance has had to have her gallbladder removed however she was not obese or even overweight to start with, was taking black market stuff from a salon and went straight in at a high dose. She’s recovered from the op but still taking whatever it is she buys from a dodgy salon, she’s rail thin now and has clearly tipped into eating disorder territory. It’s very sad.

Bipaloss · 08/05/2026 22:49

Been on it for 14 months (with a short break of 9 weeks) some nausea, some constipation (at the start) some dissyness, manour for me is cold hands and feets

nothing major and if did happen it would 1-3 days after 1-2 jabs of a dose

everyone reacts differently but most have minor SE

for me thought it has messed up my cycle started 28 day cycle consistently for 20 years , now on a random 14-24 day cycle , started with heavy painful ones now don’t feel it don’t have PMS just notice it on the scale (water retention)

handcuffed · 08/05/2026 23:06

everyone reacts differently so start low and go slow to see how you feel before moving up doses

wheresthesnowgone · 08/05/2026 23:07

No, nothing, no side effects at all. I'm steadily losing weight, a couple of pounds a week and feel great.

ExtraordinarySoph · 13/05/2026 22:45

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crumbssonmyface · 14/05/2026 03:46

Truthfully I did have side effects but not the ones I expected. I thought it would be vomiting, but in 18 months I’ve never vomited once, no matter what I eat. On the flip side, I got really crushing anxiety, heart palpitations and panic attacks caused by mj, which wasn’t really talked about when I first started on mj (now a known side effects). It means I can’t go up the doses as I’m quite sensitive to it, but as long as I stay on a low dose I’m ok. I’ve lost around 3 stone and feel so much better, and don’t regret taking it.

You might be totally fine, you might get a side effect, but also on a really positive note it can absolutely change your life in the best possible way. At first I was so shocked that I completely lost all food noise, and as a binge eater that in itself was so peaceful to experience after years of intrusive food thoughts. Sadly food noise is back now, but no where near what it used to be x

estrogone · 14/05/2026 04:14

For me I have had fatigue, headaches and recently Mounjaro Induced allodynia (skin sensitive and sore to touch - a known side effect).

I have lost 2 stone over a year.

Biosblbay · 20/05/2026 13:00

@crumbssonmyface I think this one has done it for me. I suffer quite badly with panic disorder and anxiety (especially health anxiety) so if it could make it worse I definitely won’t be doing it. I will stick to the natural and long way! Thank you for this though!

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