Does freezing fat cells kill or preserve them?

Yes of course this is confusing.  The harvest of fat to be used later is a different process that freezing your own fat and having your body remove it naturally. 

CoolSculpting has FDA approval for fat reduction since 2010. CoolSculpting freezes the fat cells. Fat cells are more susceptible to damage by freezing than the other cells, (nerve, vessel, bone, etc.), around them. The fat cells die via a process called apoptosis, (programmed cell death). The number of fat cells are therefore reduced. This happens over a period of time, so the body is not overwhelmed with dead fat cells. The body will take these cells up, process them and excrete them, just as any other cell. The remnants are filtered through the liver, and then excreted eventually via stool. CoolSculpting now has an applicator for thighs.  CoolSculpting had been used in this area with good results. See an experienced CoolSculpting practice, they will determine if you are a candidate.  Best to see a Board Certified Plastic Surgeon.  They will be able to tell you of the different options, (CoolSculpting, Liposuction, Direct excision, etc.).           

Freezing the fat cells essentially kills them.  The research has shown that the fat cells die off in a process termed apoptosis.