I think the standard 1 1/4" needle does the job for the thigh area. You MUST get the injection into the muscle. You do not want it to not reach the muscle. The 1" 25 gauge needle I'm going to get along with my next Avonex refill for my upper arm injections. Speak to your neuro because you need a prescription for the 1" 25 gauge needle. Also, speak to Biogen. They will arrange everything with your health insurance and your doctor for the smaller needle if I am not mistaken. I don't think a shorter needle than the 1" is recommended no matter how small of a build you may be. You may not get into the muscle. After doing some research, I found that they actually use the 1 1/4" needle for children (for vaccinations, etc.). Hope this helps.