The embodiment described herein are related nanoemulsions comprising botulinum toxins. In one embodiment, the nanoemulsions are prepared by high pressure microfluidization and comprise a particle size distribution exclusively between 10 and 300 nm. The nanoemulsions contemplated by the present invention are useful for the cosmetic and medical treatment of muscular contracture states. For example, botulinum toxin may relax facial muscles such that skin wrinkles become smoother and less noticeable. Further, the present invention contemplates a cosmetic formulation that may be self-administered, for example, in the privacy of one's home and without medical supervision.