Lea Michele has polycystic ovary syndrome (PCOS).
The 33-year-old actress started experiencing "brutal" symptoms of the condition, such as acne and a fluctuating weight when she finished working on 'Glee' and was desperate for answers as to what was wrong.
She told Health magazine: "The side effects can be brutal -- like weight gain and bad skin.
"Growing up, I had terrible skin. I went on Accutane three times. I was put on every medication that you could imagine to help my skin. Luckily, birth control was a saviour for me when I was in my teens. And then when I was in my late 20s, I realised I wanted to detox my body of all medications. That's when everything happened -- the return to bad skin and, this time, weight gain. I didn't know what was going on."
The 'Scream Queens' star was reluctant to take more medication but it was all medics suggested while they sought a diagnosis.
She said: "All people wanted to do was give me more medication.
"I don't shun people for needing or wanting to take medication, but for me, I knew something wasn't right. I just felt medication wasn't going to be the final cure."
Lea was eventually diagnosed with the hormone imbalance and has been able to manage her condition with a plant-based diet.
She said: "I went to a great doctor, and the minute she looked at me, she was like, 'Oh, you have PCOS.' It explained everything.
"Through diet, I have been able to manage it. But I am very fortunate. There are way more extreme versions of PCOS that women have a lot of difficulty with -- mine is not as intense.
"Which is why I haven't really talked about it, because there are women who have it so much more intense.
"Now, I feel like I am at the healthiest place in my entire life. It's not that I'm the thinnest, because I'm not the thinnest I've been. But when I was the thinnest, I was not being the healthiest. I'm definitely the most mentally, physically, and spiritually sound that I've ever been."