Bro don't worry about it. Since my accident I dropped down to 172lbs 6FT very very low BF and used a 1.5 the last 2 weeks in my ass. I am skinny as hell right now and am not having a problem. I have put on 4 lbs in 10 days natty though!!!!!!!!!!! That makes me happy. I have found the road to recovery. At my weight even 4 pounds makes a big difference. I will continue to use the same size pin. Its also kinda cool because once its in deep you can start to pull out and continue injecting. (lol, now that sounds freekin gay)