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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.

Can I half the 2.5mg dose of MJ for first few weeks

34 replies

Gizmosgremlins · 28/07/2026 10:50

I would like to start Mounjarno but worried about side effects. Does anyone know if it is possible to half dose the 2.5mg jab for the first couple of weeks?

OP posts:
MoneyJo · 28/07/2026 10:52

Yes you can. You can just take 30 clicks instead of the full 60 for a dose.

MurielTheTerrible · 28/07/2026 10:56

If you are worried about side effects, you'll presumably also worry about using the pen past 4 weeks. I'd go with 2.5 and see how you get on - you might have side effects, most people have some, but that doesn't mean they will be debilitating or last for months.

Gizmosgremlins · 28/07/2026 11:08

Thank you. I thought I could do the half dose just for the first couple of weeks to see how i adapt then up to 2.5mg. Worried about puking!

OP posts:
EvagoraY · 28/07/2026 11:25

Letting your body get used to it slowly seems like a good idea.

MoneyJo · 28/07/2026 13:14

EvagoraY · 28/07/2026 11:25

Letting your body get used to it slowly seems like a good idea.

True. Although 2.5 is already a low dose that some people claim isn't even a therapeutic dose.

HelenDenver · 28/07/2026 13:46

Yep - I get my MJ from a (private) GP and she told me that 2.5mg isn't officially at the therapeutic level, although many of her patients stay at that dose and lose weight!

EvagoraY · 28/07/2026 13:49

Every body responds differently. Plenty of people lose weight at 2.5.

HelenDenver · 28/07/2026 14:58

From the Lilly website

Provide patients with a 1-month* 2.5 mg starting dose prescription

The 2.5-mg dose is for treatment initiation and is not intended for glycemic control.

I agree 2.5mg does work for some people, but the manufacturer doesn’t market it as such.

MinnieCoops · 28/07/2026 14:59

It’s such a low dose I wouldn’t bother. It’s probably better to stay within the 30 days if you’re worried about side effects

TheRealGoose · 28/07/2026 16:27

MoneyJo · 28/07/2026 13:14

True. Although 2.5 is already a low dose that some people claim isn't even a therapeutic dose.

Yes those people inc the manufacturer.

User122333 · 28/07/2026 16:34

You can buy anti-nausea meds otc just in case

MyDarlingRose · 28/07/2026 16:35

If you want but there’s not much point.

Gizmosgremlins · 28/07/2026 16:44

Thanks all! I had a chat with a pharmacist today who said best to just start on 2.5mg as recommended. Will see how it goes 🤞

OP posts:
MoneyJo · 28/07/2026 17:35

TheRealGoose · 28/07/2026 16:27

Yes those people inc the manufacturer.

Haha fair point. I lost quite a bit on 2.5 but I have seen posts saying it didn't really do anything.

Beachforever · 28/07/2026 18:29

I started on 0.5mg, went up to 1.0mg, then 1.5mg, and finally 2.0mg. Never went higher than 2.0mg.

I lost 1.5stone in less than 12 weeks with no side effects other than appetite suppression.

HelenDenver · 28/07/2026 18:31

Sounds like you might be a super responder to Mounjaro @Beachforever as that’s so much lower than standard dosage

Beachforever · 28/07/2026 18:41

@HelenDenver yes, I guess so. I dread to think how I might have felt if I had jumped straight in at 2.5mg!

HelenDenver · 28/07/2026 18:42

Must have been a lot of click counting to get all those small doses, well done!

Beachforever · 28/07/2026 18:48

Yes, and even more now that I’m weaning myself down to find a maintenance dose.

AMurderofMurderingCrows · 28/07/2026 22:37

I tried 2.5mg and could hardly eat on it. I was existing on 300cals max a day. I eventually gave up as I was too ill to do anything but lie down 🤢

LovelyLapin · 29/07/2026 07:53

I was already following a low carb plan before I started. But I was snacking a lot on nuts. I don’t really drink alcohol.

2.5mg is giving me complete appetite suppression for almost 7 days. I’m due to take the jab at lunch time and I possibly feel a bit hungry right now. Which I haven’t all week.

For me 2.5 is definitely therapeutic.

TheRealGoose · 29/07/2026 08:06

MoneyJo · 28/07/2026 17:35

Haha fair point. I lost quite a bit on 2.5 but I have seen posts saying it didn't really do anything.

I think people misunderstand what therapeutic means. For mounjaro it is glycemic control, the medication manages your blood sugar levels.

this doesn’t mean people don’t get suppression, or are unable to lose weight on it, either due to suppression or placebo effect. It simply means yoire taking too low a dose of fne medication to control your blood sugar.

HelenDenver · 29/07/2026 08:09

Thanks for clarifying @TheRealGoose

dscugie · 29/07/2026 11:58

I wouldn’t risk wasting my money by not taking the proper dose when starting. You might find you respond really well, I did, to the point where I struggled to eat in the early days (hated this phase) but a lot of people don’t feel that straight away so you would literally be throwing money in the bin if you get no effect from it. I would highly recommend shopping for decent, healthy foods before you start and keep g a clean diet - I’m sure this reduces side effects too.

Beachforever · 29/07/2026 14:27

dscugie · 29/07/2026 11:58

I wouldn’t risk wasting my money by not taking the proper dose when starting. You might find you respond really well, I did, to the point where I struggled to eat in the early days (hated this phase) but a lot of people don’t feel that straight away so you would literally be throwing money in the bin if you get no effect from it. I would highly recommend shopping for decent, healthy foods before you start and keep g a clean diet - I’m sure this reduces side effects too.

Edited

I don’t understand the throwing money down the drain thing?

Whether you take 1.25mg from the pen or 2.5mg. The pen contains the same amount of medication and costs exactly the same.

So trying a lower dose to see if you respond well with no side effects doesn’t cost any more money. In fact, if you end up responding really well, it saves a lot of money as the higher strength pens are much more expensive.

All the clinical trails were carried out at 5mg, 10mg and 15mg. So those are the doses recommended by Eli Lilly. That doesn’t mean no other doses work.

The clinic trails did show that how well you respond to lower doses is impacted by starting weight and genetics.