CoolSculpting: Process, Side Effects, Alternatives, and More

CoolSculpting is generally a safe, low-risk procedure.

Common side effects are usually mild, and may include pain or decreased sensation in the targeted area. Some people may feel faint, nauseated, or dizzy during the procedure, or may develop a rash, swelling, or other discoloration afterward. But these side effects typically resolve on their own in the weeks following the procedure, Zeichner says.

In some cases, the procedure may result in irregular divots or ripples in the skin, Matarasso says. But this isn’t a common side effect — one review suggested this happened in 0.14 percent of procedures.

PAH, the side effect that Evangelista reported, is the best-known moderate-to-severe potential side effect of CoolSculpting, though research has not yet determined what causes it.

It occurs when CoolSculpting triggers an increase, rather than a decrease, in fat cells in the targeted area. Over the course of several months following the CoolSculpting treatment, PAH causes new tissue to grow in the shape of the treated area. The new tissue is usually harder than normal fat, and may have an almost rubbery texture, Matarasso says. Blood flow to the affected area may also increase.

In some cases, new fat growth can’t be removed using liposuction, Matarasso says, and the patient must choose between having the new tissue surgically removed or leaving it in place.

The amount of data available about the people who develop PAH is limited, Matarasso says. He adds that this is partly because the procedure is not always performed by doctors, who are required to report negative outcomes.

One clinical report suggested PAH may be underreported; the authors noted that the incidence rate of PAH at their practice was significantly higher (2 in 422, or 0.47 percent) than the incidence rate claimed by the CoolSculpting brand (1 in 20,000).

PAH may be slightly more common in males than in females, though the reason is unclear.

The study also noted that the incidence of PAH was 75 percent lower when technicians used newer-model CoolSculpting units, suggesting that the machines themselves may be a contributing factor to the risk of PAH.