Quick follow-up:
L-carnitine L-tartrate is 68% active ingrediant, with 32% of the weight being the tartrate chelate (biologically useless). So L-carnitine is like TNE, awhile L-carnitine L-tartrate is like test cyp.
Also some have gut flora that metabolize L-carnitine into TMAO, which is a toxic chemical that causes systemic inflammation. A test is available for that.
Overall injecting is just a better option.
The 500-600mg solutions are pretty thick and tedious to draw up with a 31g insulin pin, but inject easily and there is no PIP. Conversely trying to inject a few cc from a large syringe with a small needle will be difficult (easier to inject from smaller syringe). I usually do two 300mg injections, each 0.5cc subQ. Essentially zero risk of an infection from a water based subQ shot, but water based IM shots can and sometimes do result in infections, even if proper sterile technique is used.
My general rule now is water > subQ, oil > IM.