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is it normal to lose ~3/4ml when filtering?

tendency

GLP-1 Apprentice
Member Since
Oct 21, 2025
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Madison
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Just started filtering my peptides and was surprised to see I lose about 3/4 of a ml when doing so due to 'slop' in the filter and needle. Is this normal? I can't imagine people are losing this much each time they filter?
 
Just started filtering my peptides and was surprised to see I lose about 3/4 of a ml when doing so due to 'slop' in the filter and needle. Is this normal? I can't imagine people are losing this much each time they filter?
I mentioned this in my post about filtering but was told it’s not a real thing despite the fact you can literally SEE the peptide in the filter (GHK-Cu is blue). I prime before and flush afterward with bac but there’s no way to tell the exact amount in the filter. Somehow ‘random person’ figured out how to prevent the filter from absorbing, I assume she’s not using regular filters like we are, I’d ask her how she manages.
 
3/4 ml? 75 units? Sounds like a big filter. The following summarizes what I've been able to find on the subject:

You want to use the smallest possible filter as a lot of peptide gets left in the filter when you are done using it. For a few approximate examples, a 4mm filter retains about.07ml of reconstituted peptide, a 13mm retains 4x more than a 4mm at about.28ml and a 33mm filter holds a whopping.65ml.

Realistically for individuals filter reconstituted peptides you should use a 4mm filter if you are filtering less than 4ml of peptide or a 13mm filter if you are using more than that. (Source - Internet Floatilla)


I dilute so injections are not so concentrated that a few units either way doesn't make a difference. Ideally .50ml (50 units) and I try to not go lower than .30ml (30 units). I also pre wet the filter by having a bit extra bac in the barrel after reconning lyophilized vials. I remove the recon needle, pop on the filter and plunge the remainder out.
 
3/4 ml? 75 units? Sounds like a big filter. The following summarizes what I've been able to find on the subject:

You want to use the smallest possible filter as a lot of peptide gets left in the filter when you are done using it. For a few approximate examples, a 4mm filter retains about.07ml of reconstituted peptide, a 13mm retains 4x more than a 4mm at about.28ml and a 33mm filter holds a whopping.65ml.

Realistically for individuals filter reconstituted peptides you should use a 4mm filter if you are filtering less than 4ml of peptide or a 13mm filter if you are using more than that. (Source - Internet Floatilla)


I dilute so injections are not so concentrated that a few units either way doesn't make a difference. Ideally .50ml (50 units) and I try to not go lower than .30ml (30 units). I also pre wet the filter by having a bit extra bac in the barrel after reconning lyophilized vials. I remove the recon needle, pop on the filter and plunge the remainder out.
That’s exactly what I do for the same reasons. Great minds! 🥹
 
3/4 ml? 75 units? Sounds like a big filter. The following summarizes what I've been able to find on the subject:

You want to use the smallest possible filter as a lot of peptide gets left in the filter when you are done using it. For a few approximate examples, a 4mm filter retains about.07ml of reconstituted peptide, a 13mm retains 4x more than a 4mm at about.28ml and a 33mm filter holds a whopping.65ml.

Realistically for individuals filter reconstituted peptides you should use a 4mm filter if you are filtering less than 4ml of peptide or a 13mm filter if you are using more than that. (Source - Internet Floatilla)


I dilute so injections are not so concentrated that a few units either way doesn't make a difference. Ideally .50ml (50 units) and I try to not go lower than .30ml (30 units). I also pre wet the filter by having a bit extra bac in the barrel after reconning lyophilized vials. I remove the recon needle, pop on the filter and plunge the remainder out.
Yeah, you're right. Thanks for the heads up I was using too large of a filter 🙂
 
In fact flush with as much as you want to make sure the peptides come through as much as possible. Then measure the final volume (draw up into a new sterile syringe, you needn’t even pull the needle out of the vial) to calculate your final concentration.
 
I'm new and just read the post of filters, I have no idea. Do you have to filter Reta or Tirz, and what is such a filter. Can you get it in a pharmacy. I would have just bac water and the bottle and the next day I would have put it in a syringe. Sorry for the question.
 
I was quite happy I got all 6ml through the 4mm this time without it blowing or blocking.
Do the 4mm ones come with a prefilter? When I ordered the 13mm from cobetter I automatically picked the kind with a pre filter, (0.65+0.2μ) but maybe that kind will trap more volume at the end so maybe that wasn’t a good idea, does anyone know?
 
In fact flush with as much as you want to make sure the peptides come through as much as possible. Then measure the final volume (draw up into a new sterile syringe, you needn’t even pull the needle out of the vial) to calculate your final concentration.
How does that work exactly? Draw the entire vial into a syringe tells the final concentration? Will you explain a bit more, please?
 
How does that work exactly? Draw the entire vial into a syringe tells the final concentration? Will you explain a bit more, please?
Draw the entire volume into a syringe. I like to pull it all inside the barrel so the extra bit in the hub is accounted for. Using the markings on the syringe, figure out how many milliliters you have. For example if your liquid sits between the marks for 1.4ml and 3ml, you have 1.6 ml. Put everything back in the vial. If there’s a bit stuck in the hub, pull back some air from the vial and use it to push the liquid back in. Suck some air out of the vial into the syringe when you remove the needle. (Oxygen breaks down BAC, so give it a little vacuum)

Using the mg from the vial you recon’d (for example, 10.1 because you had the batch tested) you divide 10.1mg/1.6ml, giving you the concentration of your compound. Use a calculator here, left to the student as an exercise ;-)
 
Do the 4mm ones come with a prefilter? When I ordered the 13mm from cobetter I automatically picked the kind with a pre filter, (0.65+0.2μ) but maybe that kind will trap more volume at the end so maybe that wasn’t a good idea, does anyone know?
no its just the filter. I now pre wet with bac water. while I am reconning the let it sit. This seems to help. I then flush after. The Tisch 4mm are a bit tempermental sometimes. and they have blocked or blown out. I am extra gentle now.
 
no its just the filter. I now pre wet with bac water. while I am reconning the let it sit. This seems to help. I then flush after. The Tisch 4mm are a bit tempermental sometimes. and they have blocked or blown out. I am extra gentle now.
That’s a good technique, I bet it also decrease as much preferential peptide binding to the PES.

Blow out sounds bad. Not blown out onto the table, I hope!
 
That’s a good technique, I bet it also decrease as much preferential peptide binding to the PES.

Blow out sounds bad. Not blown out onto the table, I hope!
no thank goodness, into the vial and or cartridge. Creates enough bubbles to cause foam.
so then, you either suck it all out and try again or risk not doing that.. very frustrating.
 
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