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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.

How do I get 3.5mg from a 2.5mg pen?

8 replies

steinwayto · 16/03/2026 21:48

Just that really? I have read so many threads over the past 18 mi the about using a needle and how much liquid to extract but I hadn’t saved the info Blush

OP posts:
SilenceInside · 16/03/2026 22:05

So, a full dose from any strength Mounjaro pen is always 0.6ml in volume. So if you extract 0.6ml from your 2.5mg pen then that would give you a 2.5mg dose.

To work out how to get 3.5mg you just need to do a bit of simple maths. 3.5mg is 2.5mg x 1.4. You can work this out by dividing 3.5 by 2.5, which gives you the 1.4. So you then need to multiply the 0.6ml normal dose volume by 1.4, which gives you 0.84ml.

The 1ml syringes are often labelled from 0 to 100, so on that scale you would need to extract 84 units, which is the 0.84ml.

WappityWabbit · 17/03/2026 10:55

60 clicks = 2.5mg. (Divide 60 by 2.5 gives you number of clicks per 1mg)
24 clicks = 1mg

For 3.5mg….you inject one full dose (60 clicks)

(then add a fresh needle, if you’re being very fastidious and re-prime.)

Otherwise use the same needle. Then slowly twist and count 24 clicks of the pen to give you 1mg dose.

It’s really easy to adjust your doses to suit.

If you’ve reached the end of your pen and trying to extract the golden dose, you might be better off using a syringe as the click counter sometimes jams on some pens after you’ve injected 4 full doses.

It probably works for me about 50% of the time and if it jams, I grab a syringe and carry on.

steinwayto · 17/03/2026 11:54

Sorry I really wasn’t clear at all, I’m asking how to do it with a syringe. I have never done it before but I know 0.6 is a full dose I just didn’t trust myself with the maths test so work out 3.5mg into a syringe. The pen hasn’t enough clicks left for 84 but there is definitely enough to extract the amount I need.

Thank you for the help

OP posts:
MoneyJo · 26/03/2026 10:01

Does this mean you're looking at making your 4th jab from the pen 3.75 instead of 2.5?

steinwayto · 26/03/2026 10:22

MoneyJo · 26/03/2026 10:01

Does this mean you're looking at making your 4th jab from the pen 3.75 instead of 2.5?

No, it was 3.5mg and the 3rd dose

OP posts:
Itisatoughone · 26/03/2026 15:33

steinwayto · 17/03/2026 11:54

Sorry I really wasn’t clear at all, I’m asking how to do it with a syringe. I have never done it before but I know 0.6 is a full dose I just didn’t trust myself with the maths test so work out 3.5mg into a syringe. The pen hasn’t enough clicks left for 84 but there is definitely enough to extract the amount I need.

Thank you for the help

@SilenceInside , answered your question upthread.

steinwayto · 26/03/2026 15:51

Itisatoughone · 26/03/2026 15:33

@SilenceInside , answered your question upthread.

I know

OP posts:
Itisatoughone · 26/03/2026 15:53

Apologies.
Thought you hadn't seen it.

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