Air lock technique to minimize waste

After my shot last night I drew back and saw roughly 0.05 mL still in the barrel. It was a different syringe than usual so maybe that's why. I was thinking you could prime the needle until liquid appears at the tip, then inject slowly while watching the air reach the needle and stop before any air goes in.

Double-check the units. Milliliters and units are not the same, and being off by a factor of ten matters. If you're seeing 50 units left something else is wrong.

Here's my usual process: I mix a 100mg vial of the copper peptide with 3.3mL bac water so 0.1mL equals 3mg. I draw 0.1mL air into the 1mL syringe, inject that into the vial, then draw 0.1mL liquid. I tap out bubbles, push them back into the vial, and redraw to the mark. After pulling the needle off the syringe I inject subq into my belly and push the plunger fully. I still saw blue liquid in the leur-lock part, so I drew back and measured 0.05mL left in the barrel.

The numbers still don't line up. One milliliter equals 100 units. With 100mg in 330 units you're probably losing half a unit at most, or about 0.15mg. Don't push air on purpose; it's a bad idea. Plenty of online calculators exist.

Most places I checked say small amounts of air under the skin aren't harmful. The air-lock method seems pretty common, though usually described for intramuscular shots.

Two or three units of air isn't needed. A tiny accidental bubble is fine, but the source you linked was talking about twenty to thirty units. Extra air isn't required at best.

That's what started me thinking about this today. I'd dilute more but my bac water is back-ordered for weeks.

Now I'm curious. Are you really seeing 5-6 units of leftover liquid after pushing 100 units of bac water through?

With 330 units of bac water the vial is probably full; most are 3mL. To reduce site reaction you could draw your dose then pull in a bit more bac water so it mixes right in the syringe.

Yeah that link wasn't the clearest. I was just hunting for a decent general description of the technique. I filter everything into a 10mL vial. Pulling extra bac water is a good idea because it dilutes further and reduces peptide loss per shot. I'm low on bac water though and it'll be weeks before more arrives. I do have some sterile water or sodium chloride I could try instead.

I keep running into 0.2 to 0.3mL figures in multiple places. It looks like the original post just copied numbers from somewhere. If anyone has a solid reputable reference I'd like to see it. I'm open to being wrong if air lock is actually fine. It goes against everything else I've read, so I'll keep checking.

I'd probably just push slowly and stop the moment the barrel looks clear instead of going all the way to the end.

Quick update: without a Harvard-level paper I asked my sister who's a nurse. She says two to three units of air is the usual amount, just enough to clear anything stuck. Some research articles mention it can help with injection-site burn too. So the method exists, but the volumes quoted online are often way off. Learned something new.

Thanks for checking that out. Interesting to hear.

I agree with the earlier points. Even if you run the numbers on a typical kit price and common dilution, the actual dollar value of that tiny leftover is only a few cents per shot. Not worth the hassle of extra air for that amount.

I am definitely someone who overthinks this stuff a lot.

Same 31-gauge needle but only five-sixteenths of an inch long. How much loss would that be? I use 0.05mL and 1mL BD syringes.

I used the 3mL ones for years for larger injections because boxes were easy to get. Now I'm on 1mL ones that I can also get for free. Accuracy didn't matter as much with bigger volumes, but once I started using 3mL bac water for tiny doses the leftover became obvious.

Sometimes I filter the reconstituted material into a cartridge, clear the air the usual pen way, then treat the cartridge like a vial and draw from it. I label it clearly. I've never liked pushing air into vials. For some items it takes two cartridges. I like rotating between syringes with vials, syringes with cartridges, and pens.

Five-eighths of 0.42 units comes to about 0.26 units. Depending on concentration that translates to a few cents worth of product.

There are also 30-unit syringes available. I use them for anything under 20 units. Some even have half-unit markings.