The Cool Science Behind CoolSculpting

Skincare Anarchy
6 min readNov 17, 2023

By: Amy Niu

Patented by ZELTIQ Aesthetics, CoolSculpting is the trade name for cryolipolysis, a procedure that uses cold temperatures to target and eliminate fat in localized areas of the body [1]. The ZELTIQ Aesthetics CoolSculpting device was cleared by the FDA in 2012 and is a noninvasive
procedure (e.g. no use of needles, incisions, or anesthesia) [1].

Ingargiola et al. (2015) conducted a systematic review of the MEDLINE and Cochrane databases with the search algorithm “cryolipolysis OR cool sculpting OR fat freezing OR lipocryolysis,” identifying 19 articles for further review out of 319 initial results. They concluded that cryolipolysis is a promising alternative to invasive procedures such as liposuction, which come with an increased risk of complications that are inherent to surgery [2].

Writing for Harvard Health Blog, Neera Nathan and Dieter Manstein note that the human body has two types of fat — visceral fat, which lines the organs and is associated with diabetes and heart disease, and subcutaneous fat, which lies in a layer just beneath the skin. Cryolipolysis targets subcutaneous fat [3].

According to Ingargiola et al. (2015) cryolipolysis stems from the clinical observation of cold-induced panniculitis (inflammation of subcutaneous fat). The observation by Dr. Ervin Epstein and Dr. Mark Oren in 1970 was originally made in the cheek of an infant who had been sucking on a popsicle, thus leading to them coining the term “popsicle panniculitis” [4], but has since been made in adults.

Manstein et al. (2007) coined the term “cryolipolysis” for the method of freeing fat for its reduction [5]. The researchers exposed anesthetized Black Yucatan pigs to test sites with preset low temperatures and performed both gross and histological assessments of their fat contents at different intervals of post-exposure. They found that the cool conditions induced lobular panniculitis and, for some test sites, several millimeters of loss of subcutaneous fat without any damage to the overlying skin. The researchers concluded that cryolipolysis merited more research into its effects on humans, thus leading to its advent as a fat loss method through
devices like ZELTIQ’s CoolSculpting device.

Ingargiola et al. (2015) note that the studies they reviewed measured the outcomes of cryolipolysis using objective measures such as ultrasound measurements, three-dimensional imaging, and fat caliper measurements, as well as subjective measurements such as patient satisfaction surveys and investigator assessments.

The cases that used objective measures found “significant reduction in fat volume in treatment areas,” with a 14.67% to 28.5% fat caliper reduction and a 10.3% to 25.5% reduction in ultrasound measurements for the studies that used those respective measures [2]. Only one of the studies Ingargiola et al. (2015) reviewed used a validated post-treatment survey to assess patient satisfaction, which they found returned high satisfaction rates. Likewise, post-treatment investigator assessments using blinded investigators who were differentiating between pre-treatment and post-treatment photographs returned a clinically apparent “appreciable fat
reduction” [2].

Additionally, the researchers reviewed the complications due to cryolipolysis, which include bruising, swelling, sensitivity, pain, and erythema. These complications generally subsided in a few weeks after the treatment [2]. These side effects, the researchers write, are likely due to the
strength of the cryolipolysis vacuum and the cold temperature at which patient adipose tissue is kept for the duration of the treatment. One case report described a patient who developed paradoxical adipose hyperplasia — a serious side effect in which patients develop firm, well-demarcated tissue masses — following cryolipolysis treatment [2].

The researchers note that the mechanism behind cryolipolysis is not well understood, so more research into factors such as who would benefit from it and which areas of the body are most responsive to it must be investigated [2]. Indeed, the researchers report that one drawback to Ingargiola et al. (2015) is the low quantity of prospective, randomized clinical trials of high quality. In addition, there was a great amount of variability in experimental design, materials used, and measures of outcomes. These variations make comparing effect sizes and controlling
for bias difficult [2]. It should be noted that one of the researchers for Ingargiola et al. (2015), Gordon H. Sasaki, M.D., is a consultant for ZELTIQ Aesthetics, Inc [2].

Cryolipolysis is intended for fat loss, not weight loss; and since it targets subcutaneous fat, not visceral fat, it does not improve overall patient health [3]. Additionally, a technology like CoolSculpting is best for patients who already exercise regularly and maintain a healthy diet, since it targets fat that is not responsive to diet and exercise [3]. Ingargiola et al. (2015) note that cryolipolysis should not be used to treat areas with varicose veins, dermatitis, or skin lesions, nor should it be performed on people with cryoglobulinemia, cold urticaria, or paroxysmal cold hemoglobinuria.

According to the website for CoolSculpting, the device is FDA cleared for nine areas of the body: jawline, chin, upper arms, back, underarms/armpits (the location of bra fat), flank/love handles, abdomen, thighs, and buttocks [6]. The FDA classifies the CoolSculpting device as a
Class II medical device under the medical specialty of general or plastic surgery, meaning that it poses a moderate risk to consumers [7].

Class II medical device clearance requires that the device in question is substantially similar to a predecessor device that does not itself require premarket approval [8]. This is known as the 501(k) process, and the American Council on Science and Health has called it a “regulatory
loophole” [9]. The 501(k) process does not impose a clinical testing requirement on Class II medical devices seeking clearance [9].

In the case of ZELTIQ Aesthetics’ CoolSculpting device, the FDA deemed this device substantially similar to ZELTIQ Aesthetics’ Dermal Cooling Device, which is also known as the ZELTIQ Lipolysis System [7]. The Dermal Cooling Device, according to its FDA clearance as a Class II medical device, is substantially similar to the Juniper CLN1 Dermal Cooling Device [10]. According to the SEC, ZELTIQ Aesthetics, Inc. was formerly known as Juniper Medical, Inc. until the company changed its name in July 2007 [11].

CoolSculpting has been met with public scrutiny following a high-profile lawsuit filed against ZELTIQ Aesthetics by Canadian model Linda Evangelista on September 21, 2021. In a statement on Instagram, Evangelista’s attorneys allege that ZELTIQ Aesthetics failed to disclose the risk of paradoxical adipose hyperplasia to consumers who would be undergoing the cryolipolysis procedure, despite making such a disclosure to shareholders and in its SEC filings [12].

Jalian et al. (2014) reports the incidence rate of paradoxical adipose hyperplasia following cryolipolysis as 0.0051%, or roughly one in 20,000 cases [13]. However, Singh et al. (2015) reports two case studies in which cryolipolysis consumers developed paradoxical adipose hyperplasia following their treatments, which leads the researchers to conclude that the incidence rate of this side effect is underreported [14].

With public scrutiny against ZELTIQ Aesthetics, in addition to the fact that the CoolSculpting device’s FDA clearance is dependent on the clearances of earlier devices also manufactured by ZELTIQ Aesthetics and not on clinical testing, it is important for prospective CoolSculpting clients to choose a qualified cryolipolysis provider and, when researching the treatment, be wary of conflicts of interest that clinics that offer CoolSculpting may have with regards to selling the treatment.

Works Cited



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