Help protect children from gaming harms.

Take our survey

Please or to access all these features

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.

Feel so ill after first dose 😪

57 replies

FishersGate · 25/07/2026 10:06

First jab yesterday morning by 5pm I felt awful, sick lethargic headache no appetite. Had a small meal felt a little better. Woke up with a banging headache, chronic nausea. Small amount of sickness had two spoonfuls of over night oats. Had to get back into bed.

Does this pass? I am so upset I have so many friends who didnt suffer side effect 😔

I am going away in 3 weeks amd dont want to feel like this 😞.

For context 15stone and 5 5. Have FH and a few other conditions so need to get weight off.

OP posts:
FlorenceLawrence · 25/07/2026 12:15

I also had difficulty eating anything at all during the first month or so - it had such a dramatic effect on my appetite. Some evenings I would eat a tiny green salad because I couldn't stomach anything else.
It means that like me, you're a super-responder. Some people feel no effect of 2.5mg. If it's unbearable, you can try dropping down to half a dose, and see how you feel. A lot of people find the side effects subside after a couple of days.
The benefit was I lost over a stone in the first month! - which is rapid weight loss, but it did slow down in months 2 and 3.

FishersGate · 25/07/2026 12:25

FlorenceLawrence · 25/07/2026 12:15

I also had difficulty eating anything at all during the first month or so - it had such a dramatic effect on my appetite. Some evenings I would eat a tiny green salad because I couldn't stomach anything else.
It means that like me, you're a super-responder. Some people feel no effect of 2.5mg. If it's unbearable, you can try dropping down to half a dose, and see how you feel. A lot of people find the side effects subside after a couple of days.
The benefit was I lost over a stone in the first month! - which is rapid weight loss, but it did slow down in months 2 and 3.

Thank you. I have just had a very small bowl of chicken black beans lettuce but uts a struggle 😫. I am hoping it wears off. I am trying to doze as well, I haven't had great sleep thid weel which probably hasnt helped. Just with two young children cant afford nor want to write off every weekend feeling ill.

So many people seem to have zero effects so equally frustrating. Or maybe they just dont speak aboit the negatives

OP posts:
SilenceInside · 25/07/2026 12:36

@FishersGate I think that it just depends on how those side effects impact on your daily life and the trade off between that and how much weight they have to lose. When I started my BMI was 50 so I would probably have pushed through a range of side effects in order to continue. I’m also not bothered by nausea or headaches and wouldn’t consider that worth mentioning to anyone else. Tiredness can be caused by the drop in calories itself so I would consider that something that might happen an any diet if I was sticking to it.

Thistleton · 25/07/2026 12:45

I have poor tolerance of nausea and a fear of vomiting so started on a lower dose (approx 0.8mg) and took it twice a week to avoid the bigger peaks and troughs. I also increased very slowly, it worked well for me.

FishersGate · 25/07/2026 12:53

SilenceInside · 25/07/2026 12:36

@FishersGate I think that it just depends on how those side effects impact on your daily life and the trade off between that and how much weight they have to lose. When I started my BMI was 50 so I would probably have pushed through a range of side effects in order to continue. I’m also not bothered by nausea or headaches and wouldn’t consider that worth mentioning to anyone else. Tiredness can be caused by the drop in calories itself so I would consider that something that might happen an any diet if I was sticking to it.

Well there was no way I could of worked yesterday afternoon or this morning. This would absolutely impact me. Constant feeling of morning sickness 😷 is also somewhat distracting but manageable. I am not sure why people wouldn't be honest!! It helps people so much with expectations

OP posts:
FishersGate · 25/07/2026 12:53

Thistleton · 25/07/2026 12:45

I have poor tolerance of nausea and a fear of vomiting so started on a lower dose (approx 0.8mg) and took it twice a week to avoid the bigger peaks and troughs. I also increased very slowly, it worked well for me.

Thank you.

OP posts:
HelenDenver · 25/07/2026 13:05

I am not sure why people wouldn't be honest!! It helps people so much with expectations

Genuinely, many people don’t get bad side effects though.

I have taken six jabs so far. I get a mild headache the day of the jab, do some burping the day after and have had one incident of mild diarrhoea in these last weeks. I’ve never felt
so much suppression that I could barely eat.

The nature of side effects of any drug (respiratory, gastric, whatever) tends to be that a small number of people get a severe side effect and a larger number of people get a mild side effect.

FishersGate · 25/07/2026 13:08

HelenDenver · 25/07/2026 13:05

I am not sure why people wouldn't be honest!! It helps people so much with expectations

Genuinely, many people don’t get bad side effects though.

I have taken six jabs so far. I get a mild headache the day of the jab, do some burping the day after and have had one incident of mild diarrhoea in these last weeks. I’ve never felt
so much suppression that I could barely eat.

The nature of side effects of any drug (respiratory, gastric, whatever) tends to be that a small number of people get a severe side effect and a larger number of people get a mild side effect.

I think any side effects. Everyone says no side effect. Any side effect is an effect thats really my point

OP posts:
Velvetandleather · 25/07/2026 13:10

HelenDenver · 25/07/2026 13:05

I am not sure why people wouldn't be honest!! It helps people so much with expectations

Genuinely, many people don’t get bad side effects though.

I have taken six jabs so far. I get a mild headache the day of the jab, do some burping the day after and have had one incident of mild diarrhoea in these last weeks. I’ve never felt
so much suppression that I could barely eat.

The nature of side effects of any drug (respiratory, gastric, whatever) tends to be that a small number of people get a severe side effect and a larger number of people get a mild side effect.

80 percent of people have no side effects, I’m surprised any one thinks they are lying. I’ve genuinely never had any. And I’m in the majority. Of the ones who do have side effects, severe ones like the op, are a tiny percentage. It’s 1 to 2 percent.

its sad for her she can’t tolerate, but it’s far from the norm.

FishersGate · 25/07/2026 13:17

Velvetandleather · 25/07/2026 13:10

80 percent of people have no side effects, I’m surprised any one thinks they are lying. I’ve genuinely never had any. And I’m in the majority. Of the ones who do have side effects, severe ones like the op, are a tiny percentage. It’s 1 to 2 percent.

its sad for her she can’t tolerate, but it’s far from the norm.

I am unsure where you are getting your states from but over 55% if people have gastro effects thats even in clinical trials. High numbers for nausea. How manageable it is for people is of course individual.

I was merely asking whether it would pass and if anyone esle suffered. Both of your comments appear to suggest the side effects are my fault? Clearly not as wasnt suffering either prior to the medicine

A quick search of mumsnet states quite a few people get severe effects for a few days.

OP posts:
FishersGate · 25/07/2026 13:19

Velvetandleather · 25/07/2026 13:10

80 percent of people have no side effects, I’m surprised any one thinks they are lying. I’ve genuinely never had any. And I’m in the majority. Of the ones who do have side effects, severe ones like the op, are a tiny percentage. It’s 1 to 2 percent.

its sad for her she can’t tolerate, but it’s far from the norm.

Secondly your initial point regarding it being too early was also incorrect , manufacturers leaflets even states 3 to 4 hours. Maybe its not the 'norm' doesn't state it doesnt happen though

OP posts:
HelenDenver · 25/07/2026 13:23

Everyone says no side effect.

Who is the “everyone” saying this? As you say, posters on MN Mounjaro threads (including me) describe a variety of side effects.

In no way am I saying it is your fault, where did you get that from? Just as it’s not my friend’s fault she’s lactose intolerant and I’m not. Body reactions to lots of substances can vary.

SilenceInside · 25/07/2026 13:27

It’s very likely that the “everyone” that you know are genuinely not having side effects, or that they don’t warrant a mention due to being mild and manageable or perhaps they don’t want to share the personal details of any issues specific to them.

Please don’t be upset that you’ve had some side effects, as you know from MN many people do even if it’s nowhere near the majority. They are very likely to subside, you can take OTC medication for various issues and you can reduce and/or postpone your next dose(s) if necessary.

FishersGate · 25/07/2026 13:32

SilenceInside · 25/07/2026 13:27

It’s very likely that the “everyone” that you know are genuinely not having side effects, or that they don’t warrant a mention due to being mild and manageable or perhaps they don’t want to share the personal details of any issues specific to them.

Please don’t be upset that you’ve had some side effects, as you know from MN many people do even if it’s nowhere near the majority. They are very likely to subside, you can take OTC medication for various issues and you can reduce and/or postpone your next dose(s) if necessary.

Thank you appreciate this comment. Taken on board.

OP posts:
FishersGate · 25/07/2026 13:33

HelenDenver · 25/07/2026 13:23

Everyone says no side effect.

Who is the “everyone” saying this? As you say, posters on MN Mounjaro threads (including me) describe a variety of side effects.

In no way am I saying it is your fault, where did you get that from? Just as it’s not my friend’s fault she’s lactose intolerant and I’m not. Body reactions to lots of substances can vary.

Sorry not you. Other poster. 7 people i know have used it and as the side effects are 1 in 10. They all said absolutely nothing. I appreciate it all varies person to person and maybe exacerbated by my existing conditions

OP posts:
FishersGate · 25/07/2026 13:51

Sorry not you. Other poster. 7 people i know have used it and as the side effects are 1 in 10. They all said absolutely nothing. I appreciate it all varies person to person and maybe exacerbated by my existing conditions 8

OP posts:
Gardenflowering · 25/07/2026 14:07

FishersGate · 25/07/2026 12:53

Well there was no way I could of worked yesterday afternoon or this morning. This would absolutely impact me. Constant feeling of morning sickness 😷 is also somewhat distracting but manageable. I am not sure why people wouldn't be honest!! It helps people so much with expectations

OMG! Yes! It’s not a nausea from say food poisoning, it feels exactly like morning sickness, that deep pit of the stomach, whole body feeling of deep nausea. It’s bloody awful.
It doesn’t fade or go away for me for around 3 days. I now feel this nauseous when I get the pen out of the fridge in anticipation of it coming.
I’ve not moved off the sofa all day I feel so so rough.

FishersGate · 25/07/2026 14:59

Gardenflowering · 25/07/2026 14:07

OMG! Yes! It’s not a nausea from say food poisoning, it feels exactly like morning sickness, that deep pit of the stomach, whole body feeling of deep nausea. It’s bloody awful.
It doesn’t fade or go away for me for around 3 days. I now feel this nauseous when I get the pen out of the fridge in anticipation of it coming.
I’ve not moved off the sofa all day I feel so so rough.

Well at least someone is also feeling it 🤣. I had HG with both my pregnancies and it is along those lines. Along with constant burping. Trying to grt into a little and often eating routine.
.

OP posts:
Itshotinherebutainttakingoffmyclothes · 25/07/2026 19:11

FishersGate · 25/07/2026 10:49

Thanks I have been sipping water. I had already made overnight oats to make sure I had something to eat. Now sipping a protein shake to

Excellent. You need to aim for 3l a day, more if hotter. It feels like a lot at first but food contains a lot of water and if you’re eating a lot less you will taking on a lot less water.

GottaBeStrong · 25/07/2026 22:26

FishersGate · 25/07/2026 14:59

Well at least someone is also feeling it 🤣. I had HG with both my pregnancies and it is along those lines. Along with constant burping. Trying to grt into a little and often eating routine.
.

I'm here with you.

First jab on Tuesday coincided with my period starting, which probably wasn't the best timing. Anyway, I didn't feel too bad Wednesday as I am used to feeling sick (have a lot of health issues - one of which causes nausea) but Thursday, Friday and today I've felt rough and been mostly lying down on sofa or in bed, except for last night when I forced myself to do a strength training workout.

I'm drinking electrolytes in water and have upped my protein intake. Started taking multivitamin and mineral again today.

My friend has lost 4 stone doing MJ and she did have side effects. She had a lot of nausea, super reduced appetite, and sometimes vomitted in the first day or two after the injection. So I knew it wasn't necessarily going to be a walk in the park, thankfully. I plan on seeing how the next dose goes and if I am still struggling I will reduce the dose and see how that goes.

FishersGate · 25/07/2026 22:27

Itshotinherebutainttakingoffmyclothes · 25/07/2026 19:11

Excellent. You need to aim for 3l a day, more if hotter. It feels like a lot at first but food contains a lot of water and if you’re eating a lot less you will taking on a lot less water.

It has eased a little but my appetite is non existent and trying to eat anything makes me feel like it stomach is going to pop 🎉

OP posts:
FishersGate · 25/07/2026 22:29

GottaBeStrong · 25/07/2026 22:26

I'm here with you.

First jab on Tuesday coincided with my period starting, which probably wasn't the best timing. Anyway, I didn't feel too bad Wednesday as I am used to feeling sick (have a lot of health issues - one of which causes nausea) but Thursday, Friday and today I've felt rough and been mostly lying down on sofa or in bed, except for last night when I forced myself to do a strength training workout.

I'm drinking electrolytes in water and have upped my protein intake. Started taking multivitamin and mineral again today.

My friend has lost 4 stone doing MJ and she did have side effects. She had a lot of nausea, super reduced appetite, and sometimes vomitted in the first day or two after the injection. So I knew it wasn't necessarily going to be a walk in the park, thankfully. I plan on seeing how the next dose goes and if I am still struggling I will reduce the dose and see how that goes.

Thank you this reassuring but not nice !! I feel washed out. Its the nausea I can't cope with. I could put up with anything esle within reason.

I am going to do the same as you and see how next dose goes too

OP posts:
GottaBeStrong · 25/07/2026 22:39

FishersGate · 25/07/2026 22:29

Thank you this reassuring but not nice !! I feel washed out. Its the nausea I can't cope with. I could put up with anything esle within reason.

I am going to do the same as you and see how next dose goes too

Not sure if you can stand ginger, but sipping ginger beer might help. If it doesn't go away you could try some medication to combat nausea. I have some already that I take in the evening before bed.

FishersGate · 26/07/2026 09:29

GottaBeStrong · 25/07/2026 22:39

Not sure if you can stand ginger, but sipping ginger beer might help. If it doesn't go away you could try some medication to combat nausea. I have some already that I take in the evening before bed.

Yes I was sipping ginger beer yesterday afternoon. Its eased a little but I keep waking with a headache 🫠🫠. Hopefully it is going to ease off but its just getting used to it all.

OP posts:
GottaBeStrong · 27/07/2026 19:22

FishersGate · 26/07/2026 09:29

Yes I was sipping ginger beer yesterday afternoon. Its eased a little but I keep waking with a headache 🫠🫠. Hopefully it is going to ease off but its just getting used to it all.

How are you feeling today?

Dare I say it, but I feel quite a bit better today.

I did notice something that may be linked. I was feeling ill each day after I ate brunch. I wasn't fancying breakfast so I'd eat late morning and then feel awful most of the afternoon.

So today, I experimented with not eating until 2.30 p.m. and then eating just a little protein - plain chicken breast. I don't know if it was a coincidence but I felt much more normal (for me) like that.

So I will try it again tomorrow.

It's not as if I don't have anything first thing as I have a latte made with whole milk and add a scoop of collagen powder to it.

I am going to be weighing myself tomorrow morning. I need to do my next injection tomorrow. I think if I try the not eating until early afternoon and I am still feeling poorly, I will perhaps do a half dose (30 clicks).

Swipe left for the next trending thread