Botox muscle atrophy: loss of muscle volume (NOT function, specifically volume) due to prolonged Botox use?

Thank you for your question.  Botox is a neuromodulator - it works by temporarily paralyzing overactive facial muscles to prevent creasing and wrinkling of the overlying skin.  Our facial muscles are just like any other muscles in our bodies - if they are not exercised regularly, they atrophy and become smaller.  In most cases, this is actually a desired effect of treatment.  You mention volume loss after jawline injections - most of the patients I treat with Botox in the masseter muscles specifically opt for this treatment to shrink the muscles and contour the jawline.Unlike the masseters, the muscles in the glabella are quite thin and small, and do not significantly contribute to overall facial volume.  While post-Botox atrophy in this area has been studied, researchers actually needed specialized imaging technology to measure loss of muscle mass, because it was imperceptible to the naked eye.  Even in those studies, patients ultimately regained full muscle mass on imaging after discontinuing Botox treatments.  To the best of my knowledge, there is only one case report in the medical literature of unintentional facial volume loss due to cosmetic Botox treatments - and even in that case, the volume loss was not permanent.     

Thank you for your question 293739258. I understand your concern. Botox is a purified protein used to address wrinkles associated with
facial expression. When muscles are relaxed with Botox they are no longer used and get smaller. This is just like when muscles on the body get smaller when exercise is discontinued. Dr. Kalimullah provides an outstanding explanation. Please consult with a doctor for specific recommendations. Good luck!