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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 - extreme side effects

9 replies

nancyclancy123 · 14/04/2026 15:13

I started Mounjaro in November of last year. I had lost 4 stone through calorie counting and exercising but just could not shake off the last stone.

I started on the recommended 2.5mg and the first week was ok, no side effects but my appetite was very suppressed, to the point, I wasn't sure if I could deal with it. Eating felt like a chore but I did ensure I ate roughly 1500 calories a day and I made a real point of drinking a lot.

3 days after the 2nd jab, I had a really funny turn. I was at work, sitting down and suddenly felt faint, vision blurred and hearing went. I got up to go and get some fresh air and fainted very briefly. I went home and had to take 6 days off work. During this time, I felt unwell and had what I can only describe as adrenaline rush sensations n and off throughout the day. I felt wired, worse first thing in the morning and being around people made me feel worse. I couldn't stand still for too long and only felt safe laying down.

Anyway after about a week and no further injections, I completely recovered. I assumed it was the Mounjaro.

I'm still holding onto this last bit of weight and can't seem to shift it. I'm so frustrated because I do know of a few people using it successfully but no-one who has reacted in the same way. I'm now wondering if I had a dodgy batch.

Anyone else experienced similar?

OP posts:
ThirdStorm · 14/04/2026 15:44

It might have been the MJ but it might not have been. Either way it sounds like you could be a super responder and 2.5mg is very strong for you but hard to tell if you didn't take more than 2 doses. Your call if you want to try again, is it worth it if you have only the last bit to lose? Maybe you could take a smaller dose, click half way, not all the way to zero and see how you feel.

aquitodavia · 14/04/2026 16:13

You could try Wegovy, it is supposed to be less potent which could be good for you if you're very sensitive to it.

Woo383040 · 14/04/2026 16:34

Your Mounjaro dose had probably peaked when you had at your funny turn. So maybe 2.5mg is too strong for you. It was for me for the first few months. Each dose has a half life of 5 days. So some of the first dose is still in your system when take your second dose. Your second dose peaks at 24-72 hours so you had far more in your system after the second injection than with the first one. You could try counting clicks. A full dose is 60 clicks, so 30 clicks would give you a dose of 1.25mg.

nancyclancy123 · 14/04/2026 16:42

Thank you all for your advice. I agree, maybe 2.5mg is just too strong, it literally suppressed my appetite completely. I will give it some thought but I do also only have a stone left to lose which seems to be the hardest to shift.

OP posts:
Twasasurprise · 14/04/2026 16:51

You only had a stone to lose, so it was unusual to be prescribed MJ. Were you prescribed off label or was your BMI still over 30? What did your prescriber say about your reaction?

It does sound like you had an extreme reaction, if it was related to the MJ. If it was a legitimate prescription, it was unlikely to be a dodgy batch.

Overtheatlantic · 14/04/2026 16:55

The pp makes a good point about it being unlikely to be a dodgy batch if it came from a legitimate source and also asking what the prescriber said about your reaction.

Do you feel comfortable sharing more information?

Firesidechatter · 14/04/2026 19:40

How were you prescribed it when you’d only a stone to lose last year?

Kitt1 · 16/04/2026 11:24

Starting MJ when you’re not actually obese seems a risky manoeuvre.

Usually, you start off with 2.5mg with a lot of weight to lose (and high BMI) and by the time you get towards a healthy bmi, you’ll have been taking MJ for a few months and starting to taper down. By then your body has adapted and is already used to it, so minimal side effects, if any.

I’m not surprised that you had side effects if you started on 2.5mg but with a much lower bmi as there’s less fat to lose.

Also, it’s equally possible that it could have been a virus or something else completely unrelated?

NewLifter · 22/04/2026 21:17

Can I ask, did you buy from a legitimate pharmacy?

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