Lili Reinhart says she has been diagnosed with alopecia.
On Tuesday, the "Riverdale" actress shared a TikTok video of herself doing red light therapy, set to trending audio of actor Jeremy Strong describing his "Succession" character's story arc in an interview.
In the audio, which Reinhart is seen lip-syncing to, Strong says, "I am pushed beyond limits of what a person should be pushed to endure."
MORE: 'Riverdale' actress Lili Reinhart fires back at body shamers, pregnancy rumors"Was just diagnosed with alopecia in the midst of a major depressive episode," Reinhart wrote in text overlaid in the video.
She captioned the post, "Red light therapy is my new best friend. #alopecia #mentalhealth."
Alopecia is a blanket term for hair loss. According to the National Institutes of Health, there are different types of alopecia and experts believe some types occur when a person's immune system inappropriately targets their own hair follicles, which stifles hair growth.
The condition affects men and women equally, according to the NIH.
There is no cure for alopecia but there are treatments, including steroid injections and oral steroids or various immunotherapies. Red light therapy may have benefits for some patients with certain types of hair loss, but not all, according to research published in the journal Clinical, Cosmetic and Investigational Dermatology, available on the National Library of Medicine's website.
The disease can take an emotional and physical toll on those who have it.
MORE: 'Riverdale' star Lili Reinhart explains body dysmorphic disorder to criticsReinhart has been open about her issues with mental health in the past. In 2018, she opened up to Seventeen about her body dysmorphia, which she said was triggered by "really bad acne" that developed in the seventh grade.
She also took to Twitter, now X, to help her followers understand body dysmorphic disorder, which involves excessive worry about a perceived flaw in one's body, and came out with a book called "Swimming Lessons" in 2020, which documents her experience with mental health and body dysmorphia.
"Mental illness gets worse when people say that you don't have a right to feel the way you do," she wrote at the time. "That's where we are [failing]. Do not encourage this behavior. It is destructive. More destructive than you'll ever realize. You may not understand someone's insecurity- but respect it."
If you or someone you know is struggling with similar symptoms or mental health concerns, talk to your doctor. If you are experiencing thoughts of suicide, free, confidential help is available 24 hours a day, 7 days a week. Call or text the national lifeline at 988. You are not on your own.