Since its inception, CoolSculpting (aka cryolipolysis) has served as a sort of liposuction loophole—a way to attack small, discrete pockets of stubborn fat, without undergoing surgery. When performed properly, in appropriate patients, the noninvasive body treatment targets superficial fat cells, freezing them to death, without harming the skin or surrounding structures. The body then flushes out these crystallized, dead fat cells cells over the course of several weeks, gradually reducing rolls and bulges.
Following its 2010 FDA approval, the cosmetic procedure launched to great fanfare—but over the past decade, a handful of unusual fat freezing side effects have come to light. While they’re not often discussed outside of aesthetics circles, CoolSculpting hiccups are a matter of public record. To its credit, the manufacturer is very transparent about the potential reactions one could experience during or after treatment, providing on its website an exhaustive list of possible side effects, which range from the predictable—mild redness, bruising, swelling—to the unexpected: persistent pain, tongue weakness, hernia formation, paradoxical fat growth, and more. The best providers are as up-front about common side effects as they are rare ones, including some or all of these things on their consent forms.
We asked top dermatologists and plastic surgeons to weigh in on the most peculiar CoolSculpting risks and side effects, the odds of having them occur, and how they typically resolve.
5 CoolSculpting risks and side effects
1. Paradoxical adipose hyperplasia (PAH)
First described in 2014, paradoxical adipose hyperplasia (PAH) presents as “a painless area of increased fat that is very well demarcated, in the exact location of treatment with the CoolSculpting device,” explains Dr. Mathew Avram, a board-certified Boston dermatologist and the director of dermatologic surgery at Massachusetts General Hospital—home of the lab that invented cryolipolysis. (Full disclosure: Dr. Avram has served on the CoolSculpting advisory board since 2005.) According to Dr. Avram, patients who develop PAH initially see a reduction of fat, approximately two months after treatment, which is followed by an increase in fat in the treated area that clearly takes the shape of the CoolSculpting applicator. Doctors aren’t entirely sure why this happens and can’t predict in whom the freeze will backfire—but research shows that PAH is more common in men than in women.
While Dr. Avram’s 2014 paper cited the risk of PAH at approximately 1 in 20,000, “the original data seems to have understated its true incidence,” he says. While “the incidence [of PAH] is at this point unknown, our best guess is that it happens 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.
The side effect made headlines outside the medical aesthetics world recently, after supermodel Linda Evangelista took to Instagram to announce that she developed PAH after receiving seven rounds of CoolSculpting treatments. She describes being “brutally disfigured” and “permanently deformed,” 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 surefire fix for PAH (though the fat-melting injectable Kybella has been used with some success, in select cases, notes Dr. Avram). “Liposuction is the preferred method of treatment for PAH—but it’s difficult,” 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, thus challenging to remove. If it occurs in the lower abdomen and the patient has excess skin, an abdominoplasty [aka tummy tuck] is often the best treatment, because we can directly excise the damaged tissues.” On the upside, she adds, “Allergan does pay for the revisionary surgery, if the patient ‘proves their case.’”
Board-certified New York City plastic surgeon Dr. Umbareen Mahmood has also treated a number of PAH cases with 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 the same quality as [that of] native fat.” (While she says “almost all patients who’ve had CoolSculpting have some degree of fibrosis of the fat”—this irregularity is separate and distinct from true PAH.) Dr. Gordon sees the same in former CoolSculpting patients who subsequently come for liposuction—“the fat that’s left behind can get firm and scarred down,” she says, which can increase the risk of contour irregularities during lipo.
Dr. Heidi Waldorf, a board-certified dermatologist in Nanuet, New York, has never seen a case of PAH in her practice and believes updates to the CoolSculpting applicators in recent years have lessened the risk. (She currently has no financial ties to CoolSculpting.) “It was reported as a rare event with the original max applicator,” she notes, but the newer, gentler paddles “require far less suction and freeze more evenly.”
She also argues that the fat fibrosis seen in failed CoolSculpting patients undergoing lipo is perhaps not caused by the cold. As she explains, people who have fibrotic fat don’t generally respond well to CoolSculpting—and this, oftentimes, leads them to lipo for fat removal. “That would mean that the group of previously CoolSculpted patients who then have liposuction are more likely to be those with fibrotic fat. So the fat fibrosis isn’t necessarily caused by CoolSculpting but is, instead, a preexisting condition that made CoolSculpting less effective for those patients,” Dr. Waldorf theorizes. A causative link between CoolSculpting and fibrotic fat has not been established, and doctors agree that more research is needed.
While there’s no way of knowing in advance who has fibrotic fat, Dr. Waldorf warns patients that those who do have it may not see the standard 20–25% fat reduction per CoolSculpting session.
2. Pain and numbness
“Some patients report feeling 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 practice but has no relationship—financial or otherwise—with the company. These symptoms are normal and temporary and “usually present immediately after treatment and can last for a few days up to a few weeks,” Dr. Green adds.
Since CoolSculpting takes aim at lipids (or fats) and the linings of our nerves are laced with lipids, explains Dr. Avram, the cooling can actually disable cutaneous nerves. As stunned nerves gradually begin to regenerate, patients experience various sensations.
While some degree of fleeting numbness is all but guaranteed post-treatment, he says, cold-induced pain—known as pain syndrome—tends to happen, primarily, 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 have one to two weeks of “sharp, stabbing pain at the treatment site—[intense] enough to keep them awake at night—but it always goes away completely on its own,” Dr. Avram says. Some doctors prescribe gabapentin to lessen discomfort in the meantime.
3. Hernia formation
This complication is noted on the CoolSculpting site, but it’s so exceedingly rare, even some of our experts hadn’t heard of it. A hernia occurs when an organ pushes through a weak spot in the abdominal wall, creating a visible bulge. If a provider applies a CoolSculpting applicator “to an area where you have a preexisting hernia, or a weakening of the muscle wall, they could actually suction out the bowel and cause the hernia to worsen—or create a hernia where one wasn’t present but may have been on its way to occurring,” Dr. Avram explains. While he hasn’t seen this happen, he does ask all potential CoolSculpting patients about past history of hernia and examines them for preexisting hernias prior to treatment.
4. Frostbite and hyperpigmentation
Reports of CoolSculpting-related burns occasionally make headlines, but they’re “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’s been performing fat-freezing procedures. The CoolSculpting technology is, in fact, engineered to prevent these types of injuries. “The device is actually constantly determining that there’s no freezing event with the skin,” says Dr. Avram. What’s more, he adds, “the incidence of hyperpigmentation is very, very low, and we can safely treat all skin types.” The temperature for CoolSculpting—which falls in the -10°C to -15°C range—is not cold enough to freeze or stimulate pigment cells, Dr. Avram tells us.
Counterfeit cryolipolysis devices, which may lack the built-in temperature-monitoring controls of the name-brand CoolSculpting machine, have been known to cause serious skin ulcerations and should always be avoided.
5. Vasovagal symptoms (dizziness, nausea, fainting)
For some, queasiness or dizziness can punctuate any medical treatment, but our doctors say that these symptoms typically accompany invasive procedures involving blood and needles. “We see vasovagal reactions all the time—most commonly, with first-time facial injections and when starting IVs before surgery,” says Dr. Gordon. “It usually happens from an intense emotional response and/or fear and anxiety. Blood pressure and heart rate drop, and the patient can feel lightheaded and even pass out.”
CoolSculpting is completely noninvasive—yet some folks still experience vasovagal reactions during treatment. Dr. Waldorf says that she, herself, along with three of her regular CoolSculpting patients, “get light-headed 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 routinely follows fat freezing, to speed circulation and encourage faster fat-cell excretion.) She controls 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’s no risk of fall, 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 special applicator, designed to reduce double chins—and according to the company, there’s a unique set of short-term side effects that can arise when nerves and glands in the region are shocked by extreme cold. Again, these are seen so infrequently that many physicians are unfamiliar with them. Nevertheless, if you’re going a round or two with the Mini, you’ll want to ask your provider about the following could-be repercussions.
Sensation of fullness in the back of the throat
“Treatment of the submental [under-chin] fat can result in some swelling from the applicator placement,” says Dr. Green. The feeling that results—a sort of fullness or tightness in the throat—is temporary and dissipates as swelling goes down.
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 likely results when the cold affects the outer sheath of the nerve, causing it to malfunction. “The injury is temporary—there’s always full recovery of nerve function.”
Tongue deviation
It’s not as crazy as it sounds—it seems that freezing the hypoglossal nerve, which controls all tongue movements, can, rarely, weaken the tongue, causing it to temporarily veer off-center. “As the nerve regains its normal function, the tongue regains 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—causing a decrease in saliva production, but as the gland rebounds, symptoms quickly resolve.
Despite these rare side effects, a majority of RealSelf members say that CoolSculpting is Worth It for targeting unwanted fat. A thorough consultation with an experienced provider can determine whether you’re a good candidate for the noninvasive procedure and help mitigate potential CoolSculpting dangers.
