I like the reasoning but it’s flawed
First-A lot of people “vent” when heating with a needle. I’m not one of those people
Second-when brewing, the compound is filtered when warm. This requires the solution to be still heated while in open air. The BA is most commonly added last so it endures the least time through the heating process. This is to reduce the chance of evaporation but really BA in an oil solution doesn’t evaporate as easily as many think.
The problem is with the constant heating since heat degrades the raws.
I inject daily and have to heat daily for about 6-8 weeks of cooler months (what many call winter lol) since I brew slightly higher concentrations then standard.
I think the warming is close to negligible but I’m still careful to not overheat. Overheating over and over has to have and effect. So I would recommend care when heating
I wasn't going to get into heat degrading the test esters. It may happen, to a degree. but once in oil it's no longer exposed to oxygen that's a key ingredient in the degeneration process. I suspect raws brewed into the oxygen free environment of oil, along with BB, are better preserved than before they're brewed. This came up in a discussion with someone who thought his raws were degrading about whether it was better for long term storage to brew all the raws immediately or not.
The issue I'm discussing pertains to stopper quality. Especially poor, easily cored out stoppers like the one QSC has used. Warm the vial to any degree and the contents will expand, with gas of whatever, BA or air, escaping through any available opening. When it cools, it'll suck air back through that opening, which is likely humid air, and pulling in contaminants that are lying on the top of the stoppers. Repeat this 20 times for a TRT vial, and there's a good chance you're
introducing some level of contamination.
Like I said, if you're warming it's because something else in your injection process is off, and there are ways around it eliminating the need to heat.
Like using an ultra-thin walled syringe, same gauge but 50% more flow, as an example.
For me, skipping the whole warming process is just a time saver, when you're talking about several times a week. That was my main motivation to figure out how to eliminate from my injecting ritual, avoiding the other potential issues was a bonus.