Diarrhoea and taking next jab

Elliebearblues · 2025-10-20T07:01:59+00:00

Hi all, I moved up a dose to 3.75mg Monday last week and since Friday I’ve had Diarrhoea. I thought I’d gotten over it yesterday as was fine all afternoon and evening then again back on the toilet 4am this morning and a few times since, my question is should I still do my jab later today..? Thinking of going back down a dose if I do but unsure if I should even do it as the Diarrhoea still hasn’t settled. Has anyone else experienced this?

PennyPugwash · 20/10/2025 08:14

I did a 3.75 last week- never again. Not diarrhoea like you, but a tiredness I’ve never ever experienced before. I’ve felt I was in a fog all week. What I’ll do is jab 2.5 and 3 days later do 1.25 and see if split dosing works x

Ihateslugs · 20/10/2025 08:26

Snap! I’ve had diarrhoea or constipation after every jab so far! I went up to 5mg after the initial 4 weeks on 2.5mg having had diarrhoea after the first 2 then constipation after the next 2. Constipation was much easier to deal with, I managed to alleviate it by eating certain foods as advised on the NHS website so decided to move up to 5mg as I was not having much if any suppression on 2.5mg.

Unfortunately I had one bout of diarrhoea again after my first 5mg jab and a more prolonged bout after my second one last Thursday. I was really upset but will persevere for the next 2 doses to finish the pen then decide whether to carry on. As 2.5mg did not seem to help with weigh loss, I would actually stop taking Mounjaro.

I get my pens from a local pharmacy so have a monthly check up with the pharmacist, I’ll see what advice he gives me.

I had been dieting without WLIs for a few months and lost almost 2 stone but I started Mounjaro to speed up the loss before having knee replacement surgery - I had discussed this short term use with my doctor and he agreed with the decision.

Fishingboatbobbingnight · 20/10/2025 08:27

I wouldn’t necessarily blame the Jab if you had it last Monday, have already done a month on 2.5mg and (presumably) had no issues. 4 days is quite a while to link the two.
2.5mg is not an effective dose. It’s therapeutic, to check it agrees with you. The next dose up is 5mg. Not 3.75mg. Is there any reason you have decided not to follow the prescribed guidelines ?

I would go to 5mg today. That should achieve a good suppression and naturally deal with diarrhoea by having less food in your system .

(6 stone loss. Size 18/20 to Size 8. March 24 -Feb 25. MJ up the doses 2.5 per month to 15 before titration down to 5mg. Where I maintain - side effects occasional constipation)

Original poster

Elliebearblues · 20/10/2025 08:34

Fishingboatbobbingnight · 20/10/2025 08:27

I wouldn’t necessarily blame the Jab if you had it last Monday, have already done a month on 2.5mg and (presumably) had no issues. 4 days is quite a while to link the two.
2.5mg is not an effective dose. It’s therapeutic, to check it agrees with you. The next dose up is 5mg. Not 3.75mg. Is there any reason you have decided not to follow the prescribed guidelines ?

I would go to 5mg today. That should achieve a good suppression and naturally deal with diarrhoea by having less food in your system .

(6 stone loss. Size 18/20 to Size 8. March 24 -Feb 25. MJ up the doses 2.5 per month to 15 before titration down to 5mg. Where I maintain - side effects occasional constipation)

I was actually to scared to move straight to 5mg for the fear of side effects, which I ended up having with this Diorrhea anyway, Ive hardly ate for 3 days due to the Diarrhoea and also I had sickness Friday evening too. Just nervous whether to go ahead and jab today

OP posts:

Original poster

Elliebearblues · 20/10/2025 08:35

Ihateslugs · 20/10/2025 08:26

Snap! I’ve had diarrhoea or constipation after every jab so far! I went up to 5mg after the initial 4 weeks on 2.5mg having had diarrhoea after the first 2 then constipation after the next 2. Constipation was much easier to deal with, I managed to alleviate it by eating certain foods as advised on the NHS website so decided to move up to 5mg as I was not having much if any suppression on 2.5mg.

Unfortunately I had one bout of diarrhoea again after my first 5mg jab and a more prolonged bout after my second one last Thursday. I was really upset but will persevere for the next 2 doses to finish the pen then decide whether to carry on. As 2.5mg did not seem to help with weigh loss, I would actually stop taking Mounjaro.

I get my pens from a local pharmacy so have a monthly check up with the pharmacist, I’ll see what advice he gives me.

I had been dieting without WLIs for a few months and lost almost 2 stone but I started Mounjaro to speed up the loss before having knee replacement surgery - I had discussed this short term use with my doctor and he agreed with the decision.

Edited

I haven't been to bad apart from the odd fog and tiredness. This Diarrhoea is awful on day 4 so far. Just unsure what to do in terms of jabbing later or not?

OP posts:

PearlTeapot · 20/10/2025 14:01

I was hit with 3 bad days (understatement) when I did 5. So I went back down to 3.75 thinking it would help and the same thing happened. I then did 2.5 and the same. I was so unwell for 3 weeks that I came off it completely for a month and restarted as I couldn’t cope. Won’t be going up past 2.5 this time!

I would skip a week if I was you.

Original poster

Elliebearblues · 20/10/2025 17:05

PearlTeapot · 20/10/2025 14:01

I was hit with 3 bad days (understatement) when I did 5. So I went back down to 3.75 thinking it would help and the same thing happened. I then did 2.5 and the same. I was so unwell for 3 weeks that I came off it completely for a month and restarted as I couldn’t cope. Won’t be going up past 2.5 this time!

I would skip a week if I was you.

Oh never! Touch wood I seemed ok on 2.5mg definitely going back down to 2.5mg for a few weeks again

OP posts:

2old4thisshit · 20/10/2025 17:41

I have been on 2.5 since May, I have lost 14 kg, and prob got another 6-8 kg to lose, but the diarrhoea has been horrendous. Pretty much every week, twice a week, literally liquid diarrhoea, I am feeling so low about it that I want to give up, but it I’m also worried about putting weight on again.

PearlTeapot · 20/10/2025 17:51

Elliebearblues · 20/10/2025 17:05

Oh never! Touch wood I seemed ok on 2.5mg definitely going back down to 2.5mg for a few weeks again

Show quote history

I was 100% fine on 2.5 for months. I regret the day I took that 5 so so so much!

KentishMama · 20/10/2025 18:07

I have had some issues moving up doses. My endocrinologist recommended waiting until symptom free for two days before the next injection, and going down by a bit. Then stay at lower dose for at least 2 weeks before trying to increase again, and only increase by a few clicks at a time.

It's worked for me, I reached goal weight and am just maintaining now. Max dose I went to was 5 mg.

Mysticmaiden · 20/10/2025 18:55

It may be food related. A lot of MJ related diarrhoea is due to eating greasy, fatty food or heavy carbs. In my case in a year I've had it 3 times with pizza and a greasy fatty beef burger.

Periperi2025 · 20/10/2025 19:02

Fishingboatbobbingnight · 20/10/2025 08:27

I wouldn’t necessarily blame the Jab if you had it last Monday, have already done a month on 2.5mg and (presumably) had no issues. 4 days is quite a while to link the two.
2.5mg is not an effective dose. It’s therapeutic, to check it agrees with you. The next dose up is 5mg. Not 3.75mg. Is there any reason you have decided not to follow the prescribed guidelines ?

I would go to 5mg today. That should achieve a good suppression and naturally deal with diarrhoea by having less food in your system .

(6 stone loss. Size 18/20 to Size 8. March 24 -Feb 25. MJ up the doses 2.5 per month to 15 before titration down to 5mg. Where I maintain - side effects occasional constipation)

I've lost 2 1/2 stone in 14 weeks on 1.25mg (for 7 weeks) then 1.875mg, briefly went up to 2.5mg but the weight was falling off too quick considering i was below BMI 30 by this point, so back on 1.875mg for now.

What i find crazy is that the "start dose" and "therapeutic dose" is the same for men and women when we are metabolically different and men are on average significantly larger.

Maybe if more women started lower there would be a lot less side effects.

Mysticmaiden · 20/10/2025 19:07

Periperi2025 · 20/10/2025 19:02

I've lost 2 1/2 stone in 14 weeks on 1.25mg (for 7 weeks) then 1.875mg, briefly went up to 2.5mg but the weight was falling off too quick considering i was below BMI 30 by this point, so back on 1.875mg for now.

What i find crazy is that the "start dose" and "therapeutic dose" is the same for men and women when we are metabolically different and men are on average significantly larger.

Maybe if more women started lower there would be a lot less side effects.

Edited

Show quote history

It's not based on size as some women who are larger size 20+ can stay on 2.5mg for their whole journey where I started at 13st and went upto 15mg because they kept wearing off and I was ravenous. I was also prediabetic. Now I'm 9st 5.5lbs and tapered down to 7.5mg because I'm more sensitive to insulin and my prediabetes is resolved.
Dose tolerance is based on metabolic conditions ie pcos, prediabetes eg insulin resistance, production of insulin by pancreas, body's ability to use the increased insulin, number of GLP receptors, adequate fat absorption etc probably a lot more to add to this list.
I also didn't have any side effects other than low energy and could barely eat at 15mg!

SilenceInside · 20/10/2025 19:08

The research trials were majority women, and the rate of side effects was not different due to sex. The medication dosage isn't weight/size dependent.

Ihateslugs · 21/10/2025 08:10

Mysticmaiden · 20/10/2025 18:55

It may be food related. A lot of MJ related diarrhoea is due to eating greasy, fatty food or heavy carbs. In my case in a year I've had it 3 times with pizza and a greasy fatty beef burger.

My bouts of diarrhoea is definitely not linked to greasy or fatty foods as I have not eaten anything like that for months. I used to eat a lot of carbs, mainly bread, crisps, biscuits and cake but I’ve cut right back and only have two slices of seeded whole grain bread a day ( at most) and I can’t remember when I last had a biscuit or a piece of cake! Any “ sweet “ things I eat now use unrefined sugar such as bananas, applesauce, maple syrup or honey.

I actually lost almost 2 stone through dieting and intermittent fasting before starting to use Mounjaro so improved my diet significantly over the summer.

I have a monthly check up with the pharmacist at the local shop where I buy my Mounjaro and I’m sure he said that if I don’t get on with Mounjaro he would suggest other things such as Wegovy. I’m not sure about the benefits of that as I’m not seeing much impact from using Mounjaro re food suppression.

Having said that I did not eat much of my tea last night ( tuna with sweetcorn, grapes and a little grated cheese and rice cakes) but it was rather late as I fell asleep during the afternoon and the combo of ingredients did not quite work!