The Science of CoolSculpting

Subcutaneous Resistant Fat

Figure 1 depicts resistant, subcutaneous fat. Subcutaneous fat is located under the skin. This fat is called resistant when it resists the efforts of diet and exercise. Unfortunately as we age, more and more of our fat becomes resistant. Fortunately, CoolSculpting is able to treat subcutaneous fat.

Fat located inside the abdomen, between the digestive organs and abdominal wall, it termed visceral fat. CoolSculpting cannot treat visceral fat. This fat is unhealthy. Fortunately, this fat responds will to diet and exercise.

Treated Fat

Figure 2 shows fat that has been treated. The fat cells shown in blue were killed by the treatment. The fat cells begin to die within three days through a process called apoptosis.

Apoptosis is a programmed cell death. The cell creates first creates digestive enzymes. These enzyme convert the once living cell into the cellular equivalent of bouillabaisse.

Removal of Dead Fat

Figure 3 shows the treated area beginning to reduce. Reduction occurs as the immune system digests the dead fat calls. The immune system moves the tissue to the liver where it is biologically re-purposed.

The reduction is slow. It takes about two weeks for the immune system to enter the treated area. Most people begin seeing results at about six week. The treatment is about 80% resolved at three months and effectively 100% resolved at five months.

The figure also shows skin retraction. Skin retraction occurs at a slower pace. Some patients continue to see skin retract for a full 12 months.

Treatment Resolution

Figure 4 shows the treated area fully resolved. The treated area looks entirely normal, except that there are significantly less fat cells.

Adult fat cells have a very limited ability to regenerate. CoolSculpting results persist for decades. Since fat cells are being killed, the results are anticipated to persist as long as liposuction*.

The Development of CoolSculpting


CoolSculpting is based upon solid science. Studies show that a controlled chilling procedure kills just fat cells. It leaves skin, nerve and other tissues intact and unharmed.

The medical term for killing fat cells with cold is cryolipolysis. Cryolipolysis is safely performed with CoolSculpting®, a patented1 medical device.

The CoolSculpting procedure was cleared in Canada and Europe in 2009. It received FDA clearance as a class 2 medical device in 2010. At the time of this post, there have been over 5 million treatments performed, making CoolSculpting the world's most popular noninvasive fat reduction procedure.

It started with a Popsicle

The idea for CoolSculpting came from two medical studies. The first study, published in 1970, is titled Popsicle Panniculitis2. This study investigated the formation of new dimples in the cheeks of toddlers.

The common factor was that all toddlers had teething pain treated with an orally placed frozen Popsicle®. It was determined that the prolonged exposure to cold resulted in the death of just fat cells. The void from the dead fat cells is the proposed mechanism for the formation of the new dimples.

The study also found that exposure to the cold did not harm the inner lining of the mouth, the cheek muscles or nerves. The dimples gradually filled in over time. There were no further complications as the children grew.

It is thought that the filling in of the dimples is due to the regeneration of fat cells in children. Prior to puberty, fat cells have the ability to quickly regenerate. After puberty, fat cells have a very limited ability to multiply.

The other study, published in 1980, is titled Equestrian Cold Panniculitis3. This study investigated disfiguring fat loss to the inner thighs of women.

The common factor was that all the women had gone horseback riding in the winter upon frozen saddles. It was determined that the prolonged exposure to cold killed just fat cells.

Like the Popsicle study, there was no harm to skin, nerve or other tissues. Unlike the Popsicle study, the voids from the dead fat cells did not fill in over time. Since the fat loss occurred after puberty, it is assumed that the fat loss is essentially permanent.

Development of the Medical Device

The development of CoolSculpting as a medical device was a significant undertaking. The concept of using cryolipolysis as a fat reduction procedure was entirely novel. To assure safety, the FDA required investigational trials on animals before testing on humans.

The first animal study used pigs4. CoolSculpting was performed on the back of the pigs on specific days prior to tissue collection. This allowed the progress of treatment to be monitored.

Summarizing the pig results, on the day of treatment, there were no tissue changes at all. Several weeks after treatment, the immune system had infiltrated the treatment area. By three months, the immune system had vacated the treatment area. The final result showed a significant reduction of fat cells, with no impact to skin, nerve or other tissue types.

With the success of the pig study, the FDA was able to authorize an investigation trial of CoolSculpting on humans5. This trial was limited to abdominal tissue that was scheduled to be surgically removed from an elective panoplasty. A panoplasty is commonly referred to as a tummy tuck. The outcome of the human study essentially replicated safety and efficacy of the animal study.

Cryolipolysis: How Cold Kills Fat Cells

Human studies show that CoolSculpting triggers apoptosis in fat cells. Apoptosis is a highly regulated process where a cell kills itself by creating digestive enzymes. Tissue examination shows that apoptosis is limited to just the fat cells.

Exactly why apoptosis is limited to just fat cells is not entirely understood. The working model is the cryolipolysis selectively damages the membrane of fat cells. Fat cells contain mostly fat, while other cell types contain mostly water.

CoolSculpting is able to crystallize the fat in a fat cell without freezing water in other cell types. Since the crystals being formed are just inside the fat cells, only the fat cells experience membrane damage triggering apoptosis.

The membrane damage model explains another clinical observation. Massaging tissue immediately after treatment kills another 68% of fat cells6. Clearly, mechanical damage is involved with triggering apoptosis.

CoolSculpting Results Are Long Lasting

CoolSculpting results are also long lasting*. The first people to undergo CoolSculpting were test subjects treated in 2007. A follow-up study7 at 6 and 9 years post treatment demonstrates that the reduction of fat continues to persist. The persistence of results is because CoolSculpting kills fat cells and fat cells have only a very limited ability to regenerate in adults.


1 US Patent #9,308,120 details CoolSculpting

2 Epstein EH Jr, Oren ME. “Popsicle Panniculitis,” N Engl J Med. 1970 Apr 23;282(17):966-7

3 Beacham BE, Cooper PH, Buchanan CS, Weary PE. “Equestrian Cold Panniculitis.” Arch Dermatol. 1980 Sep;116(9):1025-7.

4 Zelickson B, Egbert BM, Preciado J, Allison J, Springer K, Rhoades RW, Manstein D. “Cryolipolysis for noninvasive fat cell destruction: initial results from a pig model.” Dermatol Surg. 2009 Oct;35(10):1462-70.

5 Coleman SR, Sachdeva K, Egbert BM, Preciado J, Allison J. “Clinical efficacy of noninvasive cryolipolysis and its effects on peripheral nerves.” Aesthetic Plast Surg. 2009 Jul;33(4):482-8.

6 Boey GE, Wasilenchuk JL. “Enhanced clinical outcome with manual massage following cryolipolysis treatment: a 4-month study of safety and efficacy.” Lasers Surg Med. 2014 Jan;46(1):20-6

7 Bernstein EF. “Long-term efficacy follow-up on two cryolipolysis case studies: 6 and 9 years post-treatment.” J Cosmet Dermatol. 2016 Jun 23.

*Results and patient experience may vary
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