When in doubt with anything injectable, I like to take a tiny 0.1 or 0.2 ml shot shallow in the glute, 1/2in max. If something goes wrong it's a tiny amount near the surface on a area no1 will likely be starring at unless you be stripping in the evenings lol. With carn it might burn a bit but the following day if it hasn't gotten red or swollen it's probably fine.
I'm not saying this is fool proof or a great idea, it's just what I do when I get a new source or open a new vial of anything. Or if something I didn't use up and saved for another cycle. I got 1/2 trena and 1/2 tren e that I used like a year or 2 ago. IL probably use them next summer. IL filter them and test it like I mentioned above
Same kind of idea, i've been "home brewing" my carnitine - each new batch I will take .25ml and shoot it somewhere fatty. Figure if it gets infected, better to cut out a chunk of my glute than my entire arm lol
With that, I don't store it great. A 20ml vial stays in my bathroom bag since I travel (bathroom = humidity) and it will be there for 20+ days, longer if I make an extra vial because I'm going to be gone for longer than my current vial has left.
I just make it with BAC water, about 500-600mg/mL.