The actress, 27, posted a TikTok video Monday showing her undergoing red light therapy for the condition.
In the clip, she lip-syncs to audio saying, “I’m pushed beyond the limits of what a person should be pushed to endure.”
She captioned her post: “Red light therapy is my new best friend #alopecia #mentalhealth.”
It’s unclear just what causes alopecia — officially called alopecia areata — which is an autoimmune skin disease that attacks hair follicles and causes hair loss, according to the National Alopecia Areata Foundation.
The condition, for which there is no known cure, affects as many as 6.7 million people in the US and usually affects the head and face.
Red light therapy, which is used on many skin conditions, is said to improve hair growth in people with “androgenic alopecia,” according to the Cleveland Clinic, People reports.
Actress Jada Pinkett Smith famously suffers from alopecia and has been dealing with hair loss for around six years.
“I was in the shower one day and had just handfuls of hair in my hands and I was just like, ‘Oh my God, am I going bald?’” she said on her “Red Table Talk” show in 2018.
“It was one of those times in my life where I was literally shaking in fear. That’s why I cut my hair, and why I continue to cut it,” Pinkett Smith continued.
Reinhart’s fans weighed in with comments on her video praising her for sharing her alopecia diagnosis.
“I’m so sorry you’re going through this!” one person wrote. “I’ve had alopecia for the last 2 years and know all too well how it feels. Hugs to you.”
Another fan wrote: “Thank you for using your platform to bring awareness to this. I have alopecia and my health and depression make it worse. sending love.”
Reinhart, who played Betty Cooper on the CW’s “Riverdale,” said in 2017 that she suffered from crippling anxiety. When she had “the worst panic attack of my life,” she left LA and moved back with her parents in North Carolina to deal with her anxieties.
“I remember looking at my bank account and seeing all of this money that I had saved [from] acting over the course of many years just gone,” Reinhart told W magazine at the time. “I had so much anxiety booking work, and I spent almost five months holed up in this bedroom in this house just feeling anxious, waiting for my next audition, and not doing anything else.”