It’s no secret that Mystique from the X-Men movies is totally badass. In fact, even the director of the film franchise wants the cobalt blue, shape-shifting character to have her own movie. However, getting all that body paint done isn’t exactly a party, and medical experts are actually concerned with the body paint’s health effects. Why? Because it’s jam-packed with chemicals.

“The fact is any body paint can cause an allergic reaction if an actor’s immune system has become ‘sensitive’ to a particular ingredient,” Dr. Elizabeth Tanzi, assistant clinical professor of department of dermatology at the George Washington University Medical Center and founder of Capital Laser and Skin Care, told Hollywood Reporter. “The longer the exposure, the higher the risk of sensitization to the ingredients in the body paint. However, an allergy can develop even as soon as it’s applied.”

Image zoom 20th Century Fox / giphy.com

To give you an idea of just how involved J.Law’s body paint really is, she had to stand still for seven hours of application every single time they were shooting a scene. But it’s not the process that alarmed Jennifer. “I love working with Bryan, and I love these movies,” she told Entertainment Weekly back in July. “It’s just the paint. . . I’m like, ‘I can’t even pronounce this and that’s going in my nose? I’m breathing that?’”

But is this something she should be concerned about? According to celebrity makeup artist Melissa Rogers, yes. “Body makeup is in the special effects category. Generally, special effects cosmetics are loaded with chemicals,” she told Hollywood Reporter.

Image zoom 20th Century Fox / giphy.com

Since the body paint needs to hold up under intense lighting and for long periods of time, it can trap in sweat and mess with the body’s ability to cool off. Additionally, the paint is generally alcohol-based due to longevity, and it’s removed with a solution of 99% alcohol. For this reason, celebrity esthetician Sonya Dakar — who has worked with Jennifer — adds that she often sees a “diaper rash-like side effect” on the skin, she told Hollywood Reporter: