This is is a great guide on looking at the size of the area to determine how many vials may be needed. https://cityskin.com.au/double-chin-treatment-melbourne-australia/
This can be a tricky question to give an exact answer. Everyone is different, and have different size submental fat areas. Someone with a smaller pocket in this area would normally need less treatments than someone with a large pocket. In saying that, I normally give my patients a guide to have a minimum of two treatments, to see ‘some’ result. These treatments are to be done no sooner than one month apart and some people may require 3, 4, or even 5 treatments, depending on the size of the area, and how much needs treating.