HI Betty,The botox is measured in MU or Mouse Units. It means that 1 unit generally kills a mouse 50% of the time. In lab tests. This stuff is one of the most highly toxic substances known to man. WHat it does is goes in there and kills off the nerves that control the muscle. To much at one time and you get ptosis and your eyelids will droop, or maybe a cheek will not function properly to allow you to smile, Until the nerve regenerate. That is why it has to be in the proper injection site and dosage. After that the nerves will start to rejuvenate which is why we have to continue to get the injections on an average of every 2-6 months.
Hope this helps,
Norm
*S*
