How Many Botox Units Are Needed for Laugh Lines?

IF you mean the crow's feet, there are two answers to your question. Crow's feet can be caused by two muscle actions:
1) Squinting with smiling
2) Lifting up of the cheek skin with the smile muscles acting on the corner of the mouth
In order to work on #1 above, it takes 6-12 units per side (12-24 units total) to soften the squinting muscles. YOU DO NOT WANT to weaken the smile muscles unless you have a very "gummy smile".

Hi Almis,
If you are speaking about the "crow's feet" laugh lines at the outside of the eyes, we normally inject between 12-25 units total.
If you are speaking about the laugh lines that are present between the sides of the nose and the sides of the mouth, these are addressed with dermal fillers and we inject between 1cc and 3cc of Restylane or Juvederm.

Dosage can vary and needs to be customized for each patient but in our San Francisco office we typically use 8 - 16 units per side.
The most important thing about an effective treatment is a skilled injector.
In our office I do all of our injections. Expect the same from your board certified plastic surgeon or dermatologist.
I hope this helps.