My Botox keeps wearing off after 5 weeks. What could cause this?

Thank you for your question! First of all, the dosage (whether it has been properly diluted or not), secondly the duration and the consistency of use and last but not least, the experience of the provider who does the Botox injections. There are many reasons to determine why it is not lasting as long for you. The most likely reason is simply that some people typically need more and some people need less; you might just be needing a little more than the average person due to strong muscles. You should contact your injector if you are not satisfied with the results or consult an experienced provider to help you out. Best of luck! 

The first thing that comes to mind is injection technique
and injector experience. Botox is dependent on proper injection technique and
experience. Board-certified dermatologists, plastic surgeons and their teams
should be well versed in all the proper injection techniques that we are
currently using, and we would encourage you to find out about the experience
level of the person injecting the Botox. On occasion, you will need more Botox
in certain areas, but this is not the usual case. And now with different toxins
out there, such as Dysport and Xeomin, perhaps one of the others may be more
appropriate for you moving forward.