Masseter reduction. What is the needle length to use for the masseter?

I would strongly recommend being treated by someone more experienced. I have seen numerous complications (imagine "stroke like" appearance for 6-8 weeks) when uninformed injectors attempt to treat the masseter. This is not worth the risk to you. A 1" needle is way too long in my opinion.Stephen Weber MD, FACS

Hi @wannabyoung! I recommend seeking treatments from expert injectors who have the skill and experience to precisely inject fillers into treatment areas and avoid risks and complications. I use a 30 g 1/2 needle. Best of luck, Dr. Nima!

I have used this technique for several years to help my patients reduce jaw grinding, improve symptoms of TMJ, and (cosmetically) reduce the size of their masseter muscles.  But, as Dr. Weber points out, this is not an injection that should be performed by someone with little experience.  Instead, I would also suggest that you seek out someone who has performed this procedure several times before.  
As for the needle, I generally use a 32 gauge 1/2 inch and inject BOTOX units as I see fit based upon my patient's symptoms.  
I hope that helps!  Please let me know if I can help.

A one inch needle is more than sufficient. I typically use a needle that is only 8 mm long. Using multiple locations works best for me as well. Finally, 40 units per side is a little on the high side in my experience. Have you tried a lower dose say 25-30 per side?

I agree with Stephen Weber, M.D., a one inch needle is way too long. My preference is a 30 gauge half inch Turmo needle.  I like to inject each muscle in four locations, placing about 10 units per injection.  The procedure is often very well tolerated by the patient with little discomfort.  Result begin in a few days, but unlike Botox in say the forehead area, it usually takes a couple weeks to see a true reduction in the size and strength of the muscle.  The Masseter is one of our strongest muscles.  Good luck

As long as the neurotoxin is injected into the muscle , it doesn't matter the size of the needle. I typically use a 1/2 inch needle  which is 30 gauge. 1 inch is sufficient and just a matter of physician preference