Since its introduction, CoolSculpting (also known as cryolipolysis) has served as a form of liposuction alternative – a means to target small, specific areas of stubborn fat without undergoing surgical procedures. When carried out correctly and on suitable patients, this non-invasive body treatment focuses on superficial fat cells, freezing them to death without causing harm to the skin or surrounding tissues. Over the course of several weeks, the body eliminates these crystallized, deceased fat cells, gradually reducing bulges and rolls.
Following its FDA approval in 2010, the cosmetic procedure gained significant attention – but over the past decade, a number of uncommon fat-freezing side effects have emerged. Though not frequently discussed outside aesthetic circles, CoolSculpting glitches are a matter of public record. To its merit, the manufacturer is highly transparent regarding the potential reactions one might encounter during or after treatment, providing on its website an extensive list of possible side effects, ranging from the predictable – mild redness, bruising, and swelling – to the unexpected: persistent pain, tongue weakness, hernia formation, paradoxical fat growth, and more. The top providers are equally upfront about common and rare side effects, including some or all of these on their consent forms.
We solicited the opinions of leading dermatologists and plastic surgeons regarding the most peculiar CoolSculpting risks and side effects, the likelihood of their occurrence, and how they typically resolve.
5 CoolSculpting risks and side effects
1. Paradoxical adipose hyperplasia (PAH)
Paradoxical adipose hyperplasia (PAH) was first described in 2014 and presents as “a painless area of increased fat that is clearly delineated, precisely at the treatment site of the CoolSculpting device,” explains Dr. Mathew Avram, a board-certified Boston dermatologist and the director of dermatologic surgery at Massachusetts General Hospital – the home of the lab that invented cryolipolysis. (Full disclosure: Dr. Avram has been on the CoolSculpting advisory board since 2005.) According to Dr. Avram, patients who develop PAH initially observe a reduction in fat approximately two months after treatment, followed by an increase in fat in the treated area that takes on the distinct shape of the CoolSculpting applicator. Doctors are not entirely certain why this occurs and cannot predict in whom the freezing process will backfire – but research indicates that PAH is more prevalent in men than in women.
While Dr. Avram's 2014 paper stated the risk of PAH at approximately 1 in 20,000, “the original data appears to have underestimated its true occurrence rate,” he says. While “the incidence [of PAH] is currently unknown, our best estimate is that it occurs in one in several thousand patients.”
Indeed, data from the device manufacturer estimates the rate to be around 1 in 4,000 cases. However, a more recent study reports a significantly higher incidence of 1 in 138.
This side effect made headlines outside the medical aesthetics realm recently when supermodel Linda Evangelista took to Instagram to disclose that she developed PAH after undergoing seven rounds of CoolSculpting treatments. She describes being “severely disfigured” and “permanently distorted,” even after two corrective liposuction surgeries. She has filed a lawsuit against the manufacturer of CoolSculpting, Zeltiq Aesthetics, and is seeking $50 million in damages.
Related: Linda Evangelista Says CoolSculpting “Deformed” Her. Doctors Explain What Happened.
Still, liposuction is the most reliable solution for PAH (although the fat-melting injectable Kybella has been used with some success in certain cases, as noted by Dr. Avram). “Liposuction is the preferred treatment method for PAH – but it’s challenging,” says Dr. Ashley Gordon, a board-certified plastic surgeon in Austin, Texas, who does not perform CoolSculpting. “The fat is very fibrous [or firm] and dense, making it difficult to remove. If it occurs in the lower abdomen and the patient has excess skin, an abdominoplasty [also known as a tummy tuck] is often the best option, as we can directly remove the damaged tissues.” On the positive side, she adds, “Allergan covers the cost of the revisionary surgery if the patient ‘proves their case.’”
Board-certified New York City plastic surgeon Dr. Umbareen Mahmood has also treated numerous PAH cases using power-assisted liposuction, VASER lipo, and abdominoplasty surgery. (Dr. Mahmood does not offer CoolSculpting procedures in her practice.) In her experience, “after CoolSculpting, the [treated] fat is never of the same quality as [that of] native fat.” (While she states “almost all patients who’ve undergone CoolSculpting have some degree of fat fibrosis” – this irregularity is distinct from true PAH.) Dr. Gordon observes the same in former CoolSculpting patients who subsequently come for liposuction – “the remaining fat can become firm and scarred,” she says, which can increase the risk of contour irregularities during liposuction.
Dr. Heidi Waldorf, a board-certified dermatologist in Nanuet, New York, has never encountered a case of PAH in her practice and believes that recent updates to the CoolSculpting applicators have reduced the risk. (She currently has no financial ties to CoolSculpting.) “It was reported as a rare occurrence with the original max applicator,” she notes, but the newer, more gentle paddles “require much less suction and freeze more uniformly.”
She also contends that the fat fibrosis seen in failed CoolSculpting patients undergoing liposuction may not be caused by the cold. As she explains, individuals with fibrotic fat typically do not respond well to CoolSculpting – and this often leads them to liposuction for fat removal. “This would imply that the group of previously CoolSculpted patients who then undergo liposuction are more likely to have fibrotic fat. Thus, the fat fibrosis is not necessarily caused by CoolSculpting but is instead a preexisting condition that made CoolSculpting less effective for those patients,” Dr. Waldorf theorizes. A causal link between CoolSculpting and fibrotic fat has not been established, and doctors agree that more research is necessary.
While there is no way to determine in advance who has fibrotic fat, Dr. Waldorf warns patients that those who do may not achieve the standard 20–25% fat reduction per CoolSculpting session.
2. Pain and numbness
“Some patients report experiencing numbness, tingling, or pain in the treatment area after CoolSculpting,” says Dr. Michele Green, a board-certified dermatologist in New York City, who offers the procedure in her practice but has no financial or other relationship with the company. These symptoms are normal and temporary and “usually manifest immediately after treatment and can persist for a few days to a few weeks,” Dr. Green adds.
Since CoolSculpting targets lipids (or fats) and the linings of our nerves contain lipids, explains Dr. Avram, the cooling can actually incapacitate cutaneous nerves. As stunned nerves gradually start to regenerate, patients experience various sensations.
While a certain degree of temporary numbness is almost inevitable after treatment, he says, cold-induced pain – known as pain syndrome – tends to occur, mainly when the abdomen is treated. “It’s more common with the larger CoolSculpting applicator, in my experience, than the smaller one,” Dr. Avram adds. Affected patients endure one to two weeks of “sharp, stabbing pain at the treatment site – [intense] enough to keep them awake at night – but it always disappears completely on its own,” Dr. Avram says. Some doctors prescribe gabapentin to alleviate discomfort in the interim.
3. Hernia formation
This complication is mentioned on the CoolSculpting website, but it is so extremely rare that even some of our experts were unaware of it. A hernia occurs when an organ pushes through a weak area in the abdominal wall, creating a visible bulge. If a provider applies a CoolSculpting applicator “to an area where there is a preexisting hernia or a weakening of the muscle wall, they could potentially suction out the bowel and cause the hernia to worsen – or create a hernia where one was not present but was on the verge of developing,” Dr. Avram explains. While he has not witnessed this happen, he always inquires about the past history of hernia from all potential CoolSculpting patients and examines them for preexisting hernias before treatment.
4. Frostbite and hyperpigmentation
Reports of CoolSculpting-related burns occasionally make the news, but they are “typically the result of operator error,” says Dr. Green, who has never had an incident of freezer burn or subsequent PIH (postinflammatory hyperpigmentation) in the 10-plus years she has been performing fat-freezing procedures. The CoolSculpting technology is, in fact, designed to prevent these types of injuries. “The device is constantly monitoring to ensure there is no freezing event with the skin,” says Dr. Avram. Moreover, he adds, “the incidence of hyperpigmentation is very, very low, and we can safely treat all skin types.” The temperature for CoolSculpting – which ranges from -10°C to -15°C – is not cold enough to freeze or stimulate pigment cells, Dr. Avram informs us.
Counterfeit cryolipolysis devices, which may lack the built-in temperature-monitoring controls of the branded CoolSculpting machine, are known to cause severe skin ulcerations and should always be avoided.
5. Vasovagal symptoms (dizziness, nausea, fainting)
For some, feelings of queasiness or dizziness can accompany any medical treatment, but our doctors say that these symptoms typically accompany invasive procedures involving blood and needles. “We constantly observe vasovagal reactions – most commonly with first-time facial injections and when starting IVs before surgery,” says Dr. Gordon. “It usually occurs due to an intense emotional response and/or fear and anxiety. Blood pressure and heart rate drop, and the patient can feel lightheaded and even faint.”
CoolSculpting is completely non-invasive – yet some individuals still experience vasovagal reactions during treatment. Dr. Waldorf states that she herself, along with three of her regular CoolSculpting patients, “feel lightheaded and nauseated during the initial thaw of the nerves, immediately after the applicator is removed, while the site is being treated with radio waves to break up the crystallized fat.” (This short, vigorous massage typically follows fat freezing to accelerate circulation and encourage faster fat-cell excretion.) She manages the symptoms by having juice or a snack beforehand and lying flat or in the Trendelenburg position (head down, feet elevated) during the thaw. “As long as the patient is lying down and there is no risk of falling, vasovagal is not a dangerous condition,” notes Dr. Avram. And in Dr. Waldorf's experience, the sensation usually resolves within 10 minutes, leaving patients pain-free and feeling fine.
CoolMini complications and side effects
The CoolMini is a specialized applicator designed to reduce double chins – and according to the company, there is a unique set of short-term side effects that can arise when nerves and glands in the area are affected by extreme cold. Again, these are so infrequently seen that many physicians are unfamiliar with them. Nevertheless, if you are going through one or two rounds with the Mini, you may want to inquire with your provider about the following potential consequences.
Sensation of fullness in the back of the throat
“Treating the submental [under-chin] fat can lead to some swelling from the applicator placement,” says Dr. Green. The resulting feeling – a sort of fullness or tightness in the throat – is temporary and dissipates as the swelling subsides.
Lower lip weakness
The marginal mandibular nerve – a branch of the facial nerve that runs along the lower border of the jawline – supplies the muscles of the lower lip. “There is a low incidence of marginal mandibular nerve injury with CoolSculpting,” says Dr. Avram, which is likely to occur when the cold affects the outer sheath of the nerve, causing it to malfunction. “The injury is temporary – there is always full recovery of nerve function.”
Tongue deviation
It’s not as absurd as it sounds – it seems that freezing the hypoglossal nerve, which controls all tongue movements, can, rarely, weaken the tongue, causing it to temporarily deviate from the center. “As the nerve regains its normal function, the tongue returns to its normal movement,” Dr. Green says.
Dry mouth
According to Dr. Green, cold exposure can cause swelling in the submandibular gland – one of our main salivary glands – resulting in a decrease in saliva production, but as the gland recovers, the symptoms quickly resolve.
Despite these rare side effects, a majority of Ruli members claim that CoolSculpting is Worth It for targeting unwanted fat. A comprehensive consultation with an experienced provider can determine whether you are a suitable candidate for the non-invasive procedure and help mitigate potential CoolSculpting risks.
Related: The Best Surgical and Nonsurgical Fat Reduction and Skin Tightening Procedures for Every Trouble Spot
