My question is just the opposite. Why is any test enan at 300mg/mL painful? Pullinbig has injected straight BA and he was fine, so the BA excuse doesn't make sense.
I use (human grade) test cyp at 200mg/mL. Absolutely no pain from the oil whatsoever. Maybe one of these days I'll get to try something different... even if it is still only an HRT dose.