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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 day one. When does it kick in?

14 replies

lolacherricoke · 10/01/2025 10:08

So maybe I am being naive, but I had my first jab last night and I thought that I would wake up with either side effects or a lack of appetite.
This has not happened! Will it happen, how do I know it's working?
Not sure what I expected!

OP posts:
hermionegranger · 10/01/2025 10:11

It isn't completely instant and especially when you first start, the 2.5mg is a loading dose to build up in your system so it can take a week/2 weeks to feel any effect (if you even do on 2.5mg). Don't be disheartened, but have patience for the first week and see how it goes from there.

Motnight · 10/01/2025 10:19

It really does differ from one person to another. I felt a difference straight away after my first 2.5 mg dose. Other people get up to 7.5 mg or even higher before they feel a reduction in appetite.

SilenceInside · 10/01/2025 10:26

As the others have said, there's a couple of factors here. It takes around 8 to 72 hours for the maximum level of Mounjaro to be in your system. Then, the 2.5mg dose doesn't always produce weight loss, so you may even not experience any weight loss until starting on the 5mg. Some people it takes the higher doses to get the full effect. For a small number, it may not ever really work. You won't know until you get there, so it's definitely a patience game.

TartanMammy · 10/01/2025 10:34

I'm due my second MJ tomorrow and I have to say I've felt hungry a lot of this week, so it might not have a strong appetite suppression effect. I'm going to keep going as I've heard it can take a while to have an effect and everyone is different. I've ate in calorie deficit so still expect to lose weight.

Pumpkinforever · 10/01/2025 10:40

I jabbed in the evening and the following day could barely eat. Started in November and still at 2.5mg as still losing weight in spite of suppression not being as strong as the first pen.

Look through the threads and you will find a wide variation.

Give it time.

Titasaducksarse · 10/01/2025 10:44

Started Tuesday night and Thursday ate significantly less but woke up today feeling peckish.

Stanno · 11/01/2025 15:29

Today is day two and I don’t feel any less hungry than normal.

GypsyMadness · 17/01/2025 11:43

Hi, I just started yesterday and haven’t noticed any major effects. I would assume as others have mentioned it could take a lwhile to kick in and it all depends on the dosage on when it does. Good luck and hopefully we will all see the positive effects we require.

August26 · 05/02/2025 08:47

Hi
I took my first 2.5 shot before bed and woke up with no interest of food and no side effects. The first day I had to force myself to eat three small meals as my appetite was totally suppressed. I did feel it had worn off after about 5 days as my cravings started to come back for food. The last few days had to use willpower to not start eating unhealthy snacks. Moving forward on my second jab now hopefully I can eat small meals! Good luck on your journey!

August88 · 06/03/2025 21:39

I took my first injection Tuesday evening. Wednesday i had the chills and fel nauseous all day. Today I've eaten less than usual as I haven't felt hungry.
Do you have to go up in doses gradually or could I jump from 2.5mg to 7.5mg?

SilenceInside · 06/03/2025 21:47

You'd need to persuade your pharmacy to supply you with a 7.5mg pen instead of a 5mg one which they are unlikely to do. And although you could jump up, I would absolutely not recommend it. The jump from 2.5 to 5mg is a doubling in strength. Tripling the strength would be a bad idea. And, why would you want to? I can't see what the rationale for it would be?

Oppede · 19/07/2025 11:43

Do you think if you are bigger then the 2.5 dose takes longer to work?

castleclass · 19/07/2025 11:51

Oppede · 19/07/2025 11:43

Do you think if you are bigger then the 2.5 dose takes longer to work?

I was just under 20 stone when I started and it worked straight away. It’s been so good I have stayed in that dose for 8 months .

Libbykershaw · 02/10/2025 11:08

I was on 5mg munjaro but took a 5 week break whilst we were on holiday . I have started back on 2.5mg but 4 days on and I don't feel it's kicked in yet. The very first time I took it it worked within 24 hrs. Is that normal?

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