CommunityInjection Technique

Sterility risks of adding air during vial reconstitution and transfers

85 replies40 peopleJun 20, 2026☆ Follow
Summary

how safe is introducing air into vials during mixing or transfers, and how long do reconstituted vials stay usable without contamination

participants describe venting versus deliberate air addition when moving contents to larger containers and report using the same mixed vials for eight to twenty-four weeks with no visible particles. DIY laminar flow hoods and particle counters are presented as optional ways to reduce airborne contamination, while some note that overall handling practices matter more than air alone. A nurse states that injecting air is standard practice to prevent dosing errors, yet others view the entire concern as overblown outside cleanroom settings.

What this discussion establishesWhere people disagree

whether routine air introduction creates meaningful contamination risk outside controlled environments

Still open

how long reconstituted vials remain safe and whether added precautions meaningfully change outcomes

Nothing here is advice.

85 replies · 40 people · page 1 of 2
WarmAnchor46archiveopening postJun 20

Whether or not to add air keeps coming up. I see claims daily that it risks contaminating the vial. I skip it myself. A couple people I know still do it anyway. My take is that sticking to the cleanest steps possible keeps the peptides in better shape.

RustBramble76archiveJun 20

I add air to every vial and have never run into trouble.

SlowLedger31archiveJun 20

Some vials have such strong vacuum that drawing a dose takes forever with a 31g needle and you can't use your hands for anything else during that time. You'd be old before it finishes.

NorthQuill51archiveJun 20

How does that even work for you? The vials start with vacuum inside. Is it tough to pull the peptides out?

WarmAnchor46archiveJun 20
↳ replying to @NorthQuill51

No problems here at all. 31-gauge needles are slow. 30-gauge ones move better and it comes out like an IV drip. Right now my doses are tiny, under 3 mg. With a bigger dose I can see how adding air would help.

QuietThistle70archiveJun 20

The benzyl alcohol in the BAC water is there to keep bacteria from growing for a while after mixing. I usually push in the same volume of air that I plan to draw out.

PlainAlder11archiveJun 20
↳ replying to @RustBramble76

I do the same. Not everyone does, and I skip it when filtering into a fresh vial. I usually vent so there's no pressure. Adding air makes it easier to pull the liquid into the injection syringe. Even with a 31g needle the draw from the vial is already slow.

NorthQuill51archiveJun 20
↳ replying to @PlainAlder11

Well that is still putting air into the vial.

GreyAlder39archiveJun 20
↳ replying to @WarmAnchor46 (opening post)

Yes it can introduce contamination, especially Pseudomonas which benzyl alcohol does little against. Also skin staph, fungal spores, and the whole mix of microbes you breathe out within a meter. That is why hands get disinfected or gloves used, jewelry comes off, a mask goes on, and work happens in a still clean spot. AC and fans get turned off. Nursing training videos show the proper steps. Random videos are best avoided. Reconstructions get done in batches into pen vials so venting never comes up later. A hairnet and lab coat go on during those sessions.

PlainAnchor17archiveJun 20
↳ replying to @GreyAlder39

Posts like that are why I come here, yet they also make me wonder how I am still alive. I cannot do everything suggested, but I started capping the mixed vials and wiping the caps with alcohol swabs. The mask idea sounds good so I will try that. Now I need to find out about vent needles.

WarmAnchor46archiveJun 20
↳ replying to @GreyAlder39

You follow the same steps I see in certain videos. That is solid. I already do many of the things you listed and keep a very clean space at home.

WarmCompass44archiveJun 20

For the first couple of draws I usually add air. By the third or fourth draw it is no longer needed. So I end up doing both.

IronLantern24archiveJun 20

I add air and have never had problems. If I were immunocompromised I might skip it.

GreenMeadow54archiveJun 20
↳ replying to @GreyAlder39

Most people skip all that and I have not seen reports of problems from it. Lowering risk is fine but this level feels excessive. It might fit someone with a weak immune system, otherwise it is more than I want. I know someone who goes all-in on everything and I tell him he overdoes it. This matches what he would do.

SteadySparrow75archiveJun 20

I put air in. I keep things tidy during mixing but my real worry is a vial turning cloudy before six to eight weeks. Getting sick is not the main concern.

SlowLedger88archiveJun 20

I am on the side of adding air. Skipping it is just too hard. Maybe I should practice more patience.

PlainKettle39archiveJun 20

A few times I have used a fresh syringe to pull vacuum again. Not sure it helps but it felt better. I avoid adding air when I can, yet pulling 75 units of that compound with a 31g needle is nearly impossible without a little air.

WarmAnchor46archiveJun 20
↳ replying to @SlowLedger88

I hear from others who pin ten to fifteen times. They ought to hire a nurse. That leads to another talk about pens versus syringes. I prefer syringes for many reasons but plenty of people push me toward pens. We will see. There is something about using a short needle on my stomach that feels like paying for past habits. When offered junk food I picture the needle and say no.

LevelBeacon74archiveJun 20
↳ replying to @GreenMeadow54

Ask people who inject insulin daily how they handle it.

RustQuill94archiveJun 20

Try pulling the final dose from a 60 mg vial without adding air. Good luck.

PlainAlder11archiveJun 20
↳ replying to @NorthQuill51

What are you saying? Explain the logic. Do you filter your material? Venting the new vial lets you push the mixed liquid in without pressure fighting back. The fresh vials I use start with no vacuum, so adding two or three milliliters makes the syringe push back.

GreyAlder39archiveJun 20
↳ replying to @GreenMeadow54

Overdoing it would look like the setups used in hospital pharmacies for making injectable solutions. Your friend might want to buy one of those.

QuietThistle70archiveJun 20
↳ replying to @LevelBeacon74

Exactly. My ex used to manage type 1 diabetes with multiple daily shots for over fifty years, many of them from multi-dose vials with standard syringes. New vial meant air went in first, then the dose came out. I watched it hundreds of times. People with that condition often reuse pen needles far longer than once per day and sometimes forget to swap them at all.

SteadyAnchor73archiveJun 20
↳ replying to @QuietThistle70

That is wild. Even apart from sterility, the idea of pushing the same needle back in a second time sounds painful. Pen needles included.

QuietThistle70archiveJun 20

Videos online show how people with type 1 diabetes handle their medication and some tips apply here too. I would never reuse a needle myself. After decades they get casual about it. As someone using tirzepatide for nineteen months I just finished my first box of one hundred syringes.

SteadyAnchor73archiveJun 20
↳ replying to @QuietThistle70

After half a lifetime maybe it stops bothering you, but after eight months I am still sensitive.

LevelBeacon74archiveJun 20
↳ replying to @QuietThistle70

That was my point. I worked as a paramedic for years. The only medication we filtered was amiodarone, using a needle straw for it.

SlowThistle88archiveJun 20
↳ replying to @NorthQuill51

Good question. I cannot draw without adding some air. We also have good air quality and run a HEPA purifier indoors.

LevelBeacon74archiveJun 20
↳ replying to @QuietThistle70

I will start filtering my peptides from now on.

QuietThistle70archiveJun 20
↳ replying to @LevelBeacon74

I will too. A couple of pens are on the way along with filters, cartridges, and 3 ml luer-lock syringes. I am trying pens for the first time. Reta and KPV will be added to the weekly schedule for a bit and I want to see how pens work with more frequent injections instead of once a week.

PatientBeacon15archiveJun 20
↳ replying to @RustQuill94

Exactly. You have to rock the plunger back and forth to get every last bit out.

SlowAnchor57archiveJun 20

Nurses learn on day one to draw air into the syringe.

SteadyQuill55archiveJun 20

This is one of many reasons I switched to pens early and was glad my mom did the same. No air and no vacuum to fight.

GreenMeadow27archiveJun 20
↳ replying to @WarmAnchor46 (opening post)

I only mix in front of a flow hood so any air entering a vial is clean. I also use pens.

PlainAlder11archiveJun 20
↳ replying to @LevelBeacon74

Do it. I never filtered until six vials ago. It does not add much time.

BlueAlder28archiveJun 20
↳ replying to @QuietThistle70

I used to skip adding air. On some vials I could actually see air bubbling in through an earlier puncture while drawing the next dose. Now I use pens, add air to the vial, then filter into the cartridge so the issue disappears. I mentioned this before when talking about that post on never swapping needles. A nurse with thirty-plus years said nobody outside this group changes needles for every personal shot. Your mileage may vary.

NorthQuill51archiveJun 20
↳ replying to @BlueAlder28

That does not sound right. Are you saying they draw and inject multiple times with the same needle?

NorthQuill51archiveJun 20
↳ replying to @PlainAlder11

You are describing a narrow case that does not match this thread. The original post was about adding air before drawing. Drawing a lot from a vial does create vacuum that can make pulling difficult or impossible. You either add air or vent. Either way air enters.

RustKettle57archiveJun 21
↳ replying to @WarmAnchor46 (opening post)

I do not test after I start using a vial. I just keep injecting until it clouds. I have never seen anything cloud earlier than expected.

PlainKettle39archiveJun 21
↳ replying to @NorthQuill51

I think the point is that a fresh empty vial gets a filtered vent added first, so when liquid moves over from the original vial it just displaces the air already inside. No new air is being pushed in during that step. After the transfer the new vial should stay free of vacuum, so there would be no need to add air later when drawing doses.

NorthQuill51archiveJun 21
↳ replying to @PlainKettle39

At the start there is no vacuum, but once you start pulling doses out it will develop depending on how much volume you remove.

BlueAlder28archiveJun 21
↳ replying to @NorthQuill51

Right, the comment was about multi-use pens like the ones we see here, not about reusing a disposable diabetic syringe. On a side note I ran short on needles at my current posting so I have been reusing the one on my pen for multiple shots.

WarmAnchor46archiveJun 21
↳ replying to @RustKettle57

The part about cloudiness caught my attention. I have a couple of vials I have been using for three months and they still look fine, mostly the tirzep one. How long did it take before you saw clouding? Some people I know have gone six months on the same vial. The grey-market users seem to avoid the problem that hits the folks who paid extra for pre-mixed compounder vials.

RustKettle57archiveJun 21
↳ replying to @WarmAnchor46

My reta usually runs out around week eight and it has never clouded by then. Lower doses would probably let it last longer, but the compound is gone before any cloud shows up.

PlainKettle39archiveJun 21

I set all my kits for a six-week maximum use period, so it surprises me how many plan on keeping them much longer.

QuietAnchor73archiveJun 21
↳ replying to @WarmAnchor46 (opening post)

Another place is running a test where air is added daily to vials that contain BAC and so far nothing has gone wrong. That is what the BAC is there for.

WarmAnchor46archiveJun 21
↳ replying to @QuietAnchor73

I accept that. Still some people argue that BAC only slows bacteria rather than stops it completely and that growth can still happen. I have no problem with adding air anyway.

SlowBramble67archiveJun 21

I put together a short clip showing particle counts in ordinary room air versus right in front of a laminar hood so people can judge the difference for themselves.

SlowBramble67archiveJun 21
↳ replying to @SlowAnchor57

The idea is to use the product right away rather than leaving air sitting in the vial for extended periods, and they are also taught from day one to expel any air from the syringe before injecting.

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Sterility risks of adding air during vial reconstitution and transfers · ZyraTrack Community