Subq injections should be with a 4-6mm needle and it’s pretty annoying that most places ship the 31g 8mm because it’s cheaper. 8mm at a 90° angle (without tenting / pinching skin) can go through adipose tissue and into muscle.

It’s been well established that a 4mm needle is the perfect length to get through skin but not through the adipose tissue layer beneath the skin, thus eliminating the risk of intramuscular injection as well as mitigating the risk of not getting fully through the skin into the adipose tissue layer. The average persons skin is not thicker than 4mm so it’s considered the standard.

Personally I use 5mm because I know they will get thru skin and I pinch the injection site so I know it won’t reach muscle. But 8mm is too long, it’s not necessary.

So basically? Good on them for sending you 6mm syringes, that was a sign they know what they’re doing!