Oprah Winfrey announced she is stepping down from her role at Weight Watchers after serving on its board of directors for the past nine years.

The weight-loss company enjoyed a huge boost in 2015 when Oprah signed on and shares immediately doubled. After she announced Wednesday night that she is leaving the company, shares plunged 25% in premarket trading. Weight Watchers, and other weight-loss programs, have struggled in recent years due in large part to the emergence of weight-loss drugs like Ozempic. Oprah herself revealed last year that she uses these drugs to maintain her weight. He said in her announcement she will continue “to advise and collaborate with WeightWatchers and CEO Sima Sistani in elevating the conversation around recognizing obesity as a chronic condition, working to reduce stigma and advocating for health equity.”