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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.

Has anyone had sickness and diarrhoea using 2.5mg from a 5mg pen?

5 replies

Funkylabrador · 06/05/2026 06:51

Hi 👋🏻

looking for experience!

when i first started MJ at 2.5mg in that first week I was sick & had watery diarheoa - once overnight then nothing since. I put it down to a stomach bug as my son was also sick overnight.

i’m at week 8 - i started getting 2.5mg from a 5mg pen & have done this 3 times, last 2 weeks c 48 hes after ive had bad watery diarheoa overnight & last night i was also sick.

it must be MJ. Does anyone have experience of dosing 2.5 from a 5 pen? Its sane medicine but in less liquid so more concebtrated - do you think this could be it? Will it settle?

im doing well on 2.5mg - 21lb lost in small incrememts - so happy there but using 5mg pen for cost.

ive thoughts now about only using 2mg from pen as i can’t do the extreme symptoms.

or have i just been unlucky!

welcome any thoughts or experience!

OP posts:
Itscoldouthere · 06/05/2026 13:58

Sickness and diarrhoea side effects are often down to the food you eat, have you looked at what you’ve been eating? Anything you’ve eaten the same before feeling unwell?
I can’t imagine it due to taking 2.5 from a 5, but I would probably try taking less next jab maybe 2 and see how you get on, hopefully it will pass.
Another thought is are you eating enough ? Sickness feeling is sometime down to not eating enough.

Flower1989999 · 06/05/2026 14:08

16 months into my MJ journey. Sickness amd bad tummy is common. I can honestly say I've had days where I have had good food and days where I have had bad food and been hit with a bad tummy its random and part of the MJ journey just get some immodium in. It does baffle me when people don't seem to know these issues before they start MJ.

Funkylabrador · 06/05/2026 17:28

Thanks - I am aware of the issues, just seemed odd to suddenly hit at 8/9 weeks not changed food, been really clean &prioritised protein, made sure got calories & drank plenty +electrolytes. Literally only change was microdosing the 2.5 from the 5 so wondered if that was common to drive an impact as know tummy problems can happen on the move up to 5 (so maybe it was the 5 pen!)

OP posts:
Mysticmaiden · 06/05/2026 23:56

21lbs lost in 7 weeks is 3lbs a week, higher than the average so it could be due to lack of calories, too high a deficit, not eating enough or eating the wrong types of food. Pizza did it for me, just 2 slices! I mostly stick to protein and veg but fatty foods, alcohol, red meat and heavy carbs like pasta has caused it in some people too.
How are you dosing the 2.5mg? It could be inaccurate or you could have just reached the max after so many weeks and it's too much for your body. It does build up.

Funkylabrador · 07/05/2026 08:03

Thank you! Its 8 weeks so its been 2lb a week but more these 2 weeks i’ve had a 24hour evacuation! 🙈 eating 1300 calories & 125g protein each day.

i’m doing 30 clicks of the 5mg as when i researched read that was most accurate.

its frustrating! Hoping my body gets used to whatever it as as generally feeling so much healthier & no blood sugar lows!

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