Air lock technique to minimize waste

390120

390120

GLP-1 Apprentice
Member Since
Jan 8, 2026
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I usually use 3mL syringes because I get them for free but I recently used a 1mL syringe and realized how much product I'm losing after injection that is stuck in the barrel and needle of the syringe. Especially when reconstituting amounts such as 100mg of GHK-Cu with 3mL bac and injecting 0.1mL dosages.

https://www.reddit.com/r/DrWillPowers/comments/yv37fy/comment/iweyuva
View: https://www.reddit.com/r/DrWillPowers/comments/yv37fy/comment/iweyuva/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button


  1. place draw needle on syringe
  2. draw air into syringe of equal volume to your injectable volume
  3. insert needle into vial
  4. inject air into vial
  5. draw dose to measured amount
  6. ** draw additional air into syringe of about 0.2 - 0.3 mL
  7. ** use the markings on the barrel of the syringe to measure the volume of injectable with air still in syringe and the syringe vertical with the needle upwards. for example, plunger may be at 0.5mL, top edge of injectable where it meets the air may be at 0.3mL, which equates to 0.2mL of injectable. this gets tricky with a low dead space syringe because the low dead space portion of the plunger changes the measurement; you have use the neck of the syringe where the plunger stops at full close as the line you bring the injectable back up to in order to double check your measurement.
  8. ** if using low dead space needles, draw your 0.2 - 0.3 mL of air back into syringe
  9. ** change needle (should have zero injectable in it since you last drew air into syringe)
  10. ** leave air in syringe, but flip needle facing down and make sure injectable is on the needle side and air is at the plunger side. you may need to flick the syringe while holding it farthest from the needle, in order to get all the injectable to move down towards the needle away from the plunger; you want the air going through the needle last.
  11. insert needle into body
  12. inject injectable and air. all of it.
  13. remove needle and dispose of everything
Click to expand...

Does anyone do this?

I might give it a try tonight with my injection
 
Last edited:
How much do you think you’re losing?

A 25 gauge needles has a 0.01025” inner diameter.
If it is 1” long you’re losing 1.6 units. On a HUGE needle that most would draw oil with, not go sc with water based peps.

Many use 31 gauge, 1/2” length, that’s about 0.42u lost.

Injecting units of air to avoid a fraction of a unit lost is … baffling.

I’ve hit blood vessels a few times, yesterday in fact, no way I’m signing up to push anything more than an incidental bubble on purpose.

TLDR:
This person has zero interest in your health. Proceed with caution.
 
Foggy-Hollow said:
How much do you think you’re losing?

A 25 gauge needles has a 0.01025” inner diameter.
If it is 1” long you’re losing 1.6 units. On a HUGE needle that most would draw oil with, not go sc with water based peps.

Many use 31 gauge, 1/2” length, that’s about 0.42u lost.

Injecting units of air to avoid a fraction of a unit lost is … baffling.

I’ve hit blood vessels a few times, yesterday in fact, no way I’m signing up to push anything more than an incidental bubble on purpose.

TLDR:
This person has zero interest in your health. Proceed with caution.
Click to expand...
I pulled back my syringe after injection last night and found about .5mL in the barrel? It wasn’t the typical needle I usually use though so it may be because of the syringe type?

I was thinking you could prime the needle until you see the medication start to come out so you don’t inject air first, and slowly inject the GHK-Cu and watch the air as it enters the barrel before the needle and pull it out then, ensuring no air is injected
 
390120 said:
I pulled back my syringe after injection last night and found about .5mL in the barrel? It wasn’t the typical needle I usually use though so it may be because of the syringe type?

I was thinking you could prime the needle until you see the medication start to come out so you don’t inject air first, and slowly inject the GHK-Cu and watch the air as it enters the barrel before the needle and pull it out then, ensuring no air is injected
Click to expand...

Check the syringe math. You’re missing a power of ten which can be dangerous. mL is different than units. If you have 50 units left over there’s other things going on.
 
Foggy-Hollow said:
Check the syringe math. You’re missing a power of ten which can be dangerous. mL is different than units. If you have 50 units left over there’s other things going on.
Click to expand...
Here’s what I do

I reconstitute a 100mg vial of GHK-Cu with 3.3mL of Bac water which gives me 0.1mL = 3mg

I’m currently using 3mg daily

I draw my 1mL syringe to 0.1mL and inject that air into the vial and draw until I get 0.1mL, I tap the syringe and get all the air bubbles at the top and push it back into the vial and draw again to the 0.1mL mark. Then I take the needle out of the syringe

I inject it subq into my belly and push plunger all the way down. I noticed blue still in the barrel of the leur lock connector so I pulled it back to see how much there was

After I removed the needle from my body I drew back the plunger and read from the graduated marks on the barrel there was 0.05mL of GHK-Cu still in the barrel

edit, i meant 0.05mL , not 0.5mL after i was reading what i wrote
 
Last edited:
390120 said:
reconstitute a 100mg vial of GHK-Cu with 3.3mL of Bac water which gives me 0.1mL = 3mg
Click to expand...

It doesn’t. You’re off by x100 here.

1 mL is 100 units. You have 100 mg suspended in 330 units.

You have probably half a unit hung up, 0.15mg.

Don’t inject air, it is very bad.

There are many calculators on line.
 
Lots of thinking here. My way. I pull out to the amount required empty, push the air in, and draw out the liquid plus a mg, tap any bubbles and push the syringe to the required amount and blast away. This 100% my opinion and the way I do it.
 
Foggy-Hollow said:
It doesn’t. You’re off by x100 here.

1 mL is 100 units. You have 100 mg suspended in 330 units.

You have probably half a unit hung up, 0.15mg.

Don’t inject air, it is very bad.

There are many calculators on line.
Click to expand...
Everywhere i search online says small amounts of air injected subq is not harmful

And seems like the air lock method is commonly used, although for IM injections
 
Last edited:
The needle/syringe 'slop' can start to add up especially if you don't dilute much. eg, I use a 1ml syringe or 100 units. Typically, this will result in 5-6 'slop' units per injection.

Now, if you've diluted you product to, say, 10 units = 1mg then you're losing 1/2 mg per injection which can be significant wastage.

I typically dilute generously to minimize the mg loss.
 
tendency said:
The needle/syringe 'slop' can start to add up especially if you don't dilute much. eg, I use a 1ml syringe or 100 units. Typically, this will result in 5-6 'slop' units per injection.

Now, if you've diluted you product to, say, 10 units = 1mg then you're losing 1/2 mg per injection which can be significant wastage.

I typically dilute generously to minimize the mg loss.
Click to expand...
That’s what got me on this tangent today, I would dilute with more but my Bac water supplier is on back order for weeks now
 
390120 said:
That’s what got me on this tangent today, I would dilute with more but my Bac water supplier is on back order for weeks now
Click to expand...
If you’re using 330 units of BAC you’re probably got the pep vial full, usually they’re 3mL. Maybe it’s a 5mL?

If you’re wanting to ease site reaction pull your shot then pull in some BAC, it’ll mix in the syringe.
 
Foggy-Hollow said:
2-3u of air is unnecessary. Yes the incidental bubble is fine. The link led to a post saying 20-30units.
Zero extra air is unnecessary at best.
Click to expand...
yea not the best link perhaps, I was just looking for something with a good general guideline of technique
Foggy-Hollow said:
If you’re using 330 units of BAC you’re probably got the pep vial full, usually they’re 3mL. Maybe it’s a 5mL?

If you’re wanting to ease site reaction pull your shot then pull in some BAC, it’ll mix in the syringe.
Click to expand...
I filter it into a 10mL vial,

That's a good point about pulling in more BAC, that would also further dilute the concentration and lead to less loss of the peptide

I'm short on BAC though unfortunately, going to be a few weeks till i get more so I'm trying to make it last. I do have some NaCl or sterile water for injection I can get which could work
 
390120 said:
And seems like the air lock method is commonly used, although for IM injections
Click to expand...

I keep seeing 0.2 to 0.3mL in several texts!
Look like the Reddit author copied what was found online.

If anyone has a reliable reputable source I’d love to see it.

I’m happy to be wrong if air lock is legit. It seems very contrary to everything else I’ve seen. I’ll keep digging in the meantime.
 
390120 said:
I usually use 3mL syringes because I get them for free but I recently used a 1mL syringe and realized how much product I'm losing after injection that is stuck in the barrel and needle of the syringe. Especially when reconstituting amounts such as 100mg of GHK-Cu with 3mL bac and injecting 0.1mL dosages.



Does anyone do this?

I might give it a try tonight with my injection
Click to expand...
As for this technique, meh, personally I wouldn't want to be injecting that large of an air bubble. I'll just generously dilute to minimize the slop loss, that's my .02 cents anyhow.
 
tendency said:
As for this technique, meh, personally I wouldn't want to be injecting that large of an air bubble. I'll just generously dilute to minimize the slop loss, that's my .02 cents anyhow.
Click to expand...
I would probably just inject very slowly and stop once i see the barrel become clear of the peptide instead of pushing the plunger all the way
 
390120 said:
yea not the best link perhaps, I was just looking for something with a good general guideline of technique

I filter it into a 10mL vial,

That's a good point about pulling in more BAC, that would also further dilute the concentration and lead to less loss of the peptide

I'm short on BAC though unfortunately, going to be a few weeks till i get more so I'm trying to make it last. I do have some NaCl or sterile water for injection I can get which could work
Click to expand...

Reporting back: short of finding an article from Harvard Medical (I won’t) I asked my BSN sister.

She says it’s 2-3 units of air. Not much but enough to clear out what may be hung up.

The research articles I came across say it helps with the burn. So it definitely is out there but for some reason the volume of air is off. TIL.
 
Foggy-Hollow said:
Reporting back: short of finding an article from Harvard Medical (I won’t) I asked my BSN sister.

She says it’s 2-3 units of air. Not much but enough to clear out what may be hung up.

The research articles I came across say it helps with the burn. So it definitely is out there but for some reason the volume of air is off. TIL.
Click to expand...
Thank you for looking into it, that is interesting to know
 
i would also say that if your doing 30 unit injections, use a 50 unit/.5ml syringe. i think more accurate and slightly less waste that a 100 unit in my opinion. no science tested, just observation.
 
It's wild how much weapons-grade overthinking can be solved by "ok, get a pen then."

It could also be solved by "oh for heaven's sake stop that" but people aren't going to do that, and I overthought when I was brand new too, so a pen probably is the more realistic solution to the tendency to weapons-grade overthink.

Don't like air in the vials? Ok, get a pen.
Don't like wasting a whole syringe very day? Ok, get a pen.
Don't like being confused about which pep is which? Ok, get several pens of different colors.
Don't like (whatever all this is)? Ok, get a pen.
 
Foggy-Hollow said:
How much do you think you’re losing?

A 25 gauge needles has a 0.01025” inner diameter.
If it is 1” long you’re losing 1.6 units. On a HUGE needle that most would draw oil with, not go sc with water based peps.

Many use 31 gauge, 1/2” length, that’s about 0.42u lost.
Click to expand...
Also, strong agree with everything FH said, but if you're still agonizing...assuming you bought a kit of T-30 for $135 (it's prolly cheaper now, but that's what I paid in August when I was still buying 30's), and reconned it at 22mg/ml (which I do because I started on Brello and that's their dosage), then your waste for the 1.6 units (which would be bizarre to be using a needle that big anyway) would be about sixteen cents, and for the 0.42 units, four cents.

If some guy ran up to me, brandishing a syringe, and screamed "GIMMIE SIXTEEN CENTS OR I'LL INJECT A TINY AIR BUBBLE UNDER YOUR SKIN" I'd give bro the sixteen cents even if I had my pepper spray on me, because Jesus Christ, it's worth sixteen cents to avoid all that.
 
390120 said:
That’s what got me on this tangent today, I would dilute with more but my Bac water supplier is on back order for weeks now
Click to expand...
injectionshop or underground supply both reasonable prices and fair shipping and deliver in a couple days....
 
skeptick said:
injectionshop or underground supply both reasonable prices and fair shipping and deliver in a couple days....
Click to expand...
I ordered from these guys the beginning of Jan so I’m right at the cusp of getting my order… hopefully

www.midwiferysupplies.ca

Bacteriostatic Water for Injection 30mL | Hospira Pfizer

Always fresh expiry dates. Authentic Hospira Pfizer Bacteriostatic Water 30mL multi-dose vial. Sterile water with 0.9% benzyl alcohol preservative for diluting, dissolving, or reconstituting medications.
www.midwiferysupplies.ca www.midwiferysupplies.ca

Just need to hold on a bit longer
 
randompersonrandom said:
It's wild how much weapons-grade overthinking can be solved by "ok, get a pen then."

It could also be solved by "oh for heaven's sake stop that" but people aren't going to do that, and I overthought when I was brand new too, so a pen probably is the more realistic solution to the tendency to weapons-grade overthink.

Don't like air in the vials? Ok, get a pen.
Don't like wasting a whole syringe very day? Ok, get a pen.
Don't like being confused about which pep is which? Ok, get several pens of different colors.
Don't like (whatever all this is)? Ok, get a pen.
Click to expand...
I am definitely a weapons grade overthinker 😂😂😂
 
390120 said:
I usually use 3mL syringes because I get them for free but I recently used a 1mL syringe and realized how much product I'm losing after injection that is stuck in the barrel and needle of the syringe. Especially when reconstituting amounts such as 100mg of GHK-Cu with 3mL bac and injecting 0.1mL dosages.



Does anyone do this?

I might give it a try tonight with my injection
Click to expand...
I use this chart.
 

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Stop being cheap and using a 3ml syringe because it's free. A 1ml insulin syringe is cheap, if you can afford peptides, then you can afford the correct equipment for your injection. Amazon has 25 1ml syringes with needle for $12.88 A 1ml syringe is much more accurate for dosing, and it won't have as much peptide left in the barrel, which is very little anyway. You probably have much more important things to worry about in your life.

Listen up, if you buy a box of 100mg GHK-CU for $50 , then you have 1000mg all together. That will give you 333, 3mg injections for a cost of 15 cents per injection. Seriously, are you going to risk injecting air for less than $0.15 😎
 
Lovedog100 said:
Stop being cheap and using a 3ml syringe because it's free. A 1ml insulin syringe is cheap, if you can afford peptides, then you can afford the correct equipment for your injection. Amazon has 25 1ml syringes with needle for $12.88 A 1ml syringe is much more accurate for dosing, and it won't have as much peptide left in the barrel, which is very little anyway. You probably have much more important things to worry about in your life.

Listen up, if you buy a box of 100mg GHK-CU for $50 , then you have 1000mg all together. That will give you 333, 3mg injections for a cost of 15 cents per injection. Seriously, are you going to risk injecting air for less than $0.15 😎
Click to expand...
I used 3mL ones for TRT for years because I could get boxes of them, but I am using 1mL ones now because I can get those for free from work now too LOL

I didn't consider accuracy as much before since I was injecting larger quantities but since I started reconstituting with amounts such as 3mL BAC and injecting much smaller doses is when I noticed this
 
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