Pernicious Anaemia Society
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How to know if you hit a vein in the thigh?


I have had to go down the route of self IM in the thigh. I am new to IM, so I am not sure what to expect?

I have found that Neurobion 3 ml ampoules are available in the local pharmacies. I am using blue needles. The pharmacy had given me only 2.5 ml syringes, which meant that they were full to the brim, so I could not draw back!

I am worried that I may already have injected into a vein, but I have not had any significant side effects, if I actually had injected into a vein?

I have done 4 injections so far. The 1st one ached quite a bit for a couple of days. The 2nd one (in the opposite thigh) hurt a bit while injecting. The 3rd one was ok. The 4th one was also ok. I suspect that I just injected too fast in the 1st 2 injections? It is 3 ml to inject, and very thin liquid. In the 1st 2 injections, I pushed the plunger and "whoosh", 1-2 seconds later it was all gone! No resistance at all! For the 3rd and 4th injections, I took it a lot slower (inject a little bit, stop for a few seconds, inject a bit more).

Anyway, back to my question. I have managed today to get 5 ml syringes. I will now be able to draw back, but what am I actually looking for? All the posts I have read say that if you see blood being drawn up, then stop and inject in another location. As the B12 is red in colour anyway, is it something that is very obvious to see, if I do hit a vein?

Any advice gratefully received.

I am pleased to report that most of my symptoms are a lot less severe now.


4 Replies

I don't worry about veins and I don't draw back to check.

Go buy a nice slice of ham - the piggy equivalent of your thigh muscle. Do you see lots of large veins in it? Do you see any veins in it?

You can tell if the needle has passed through a vein when you withdraw it. If there's more than a little drop of blood then you've gone through a small vein. But that's more likely to have been in the skin rather than the muscle.

And even if you do inject straight into the vein it's no big deal. Some people swear by infusions of B12 straight into a vein.



Thanks for alleviating my fears.

It is all a bit scary stuff when 1st starting self IM.

I hope it gets easier with time?




It definitely gets easier the more you do. I must be somewhere around the 50 mark now (my partner and I take turns). I now prefer to do it myself than have a nurse do it.

I know I hit a vein once because it bled quite a bit when I took the needle out, but I knew it couldn't do me any harm so I didn't worry about it.


Thanks for the moral support.



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