AI Is Helping Doctors Answer Tough Medical Questions as OpenEvidence Surges
Nearly two-thirds of U.S. physicians are now using artificial intelligence to help answer complex clinical questions, driven by the rapid adoption of OpenEvidence, a Miami-based startup that has become one of the most widely embraced AI tools in American medicine. The platform, founded in 2022 by Daniel Nadler and Zachary Ziegler, functions as an AI-powered medical search engine that allows doctors to ask clinical questions in natural language and receive answers grounded in peer-reviewed medical literature.
As of mid-2026, approximately 650,000 U.S. doctors — about 65% of all physicians — actively use OpenEvidence, according to NBC News. Another 1.2 million healthcare professionals use the platform internationally. In April alone, the tool was used in roughly 27 million clinical encounters.
The Problem OpenEvidence Solves
Physicians face an increasingly daunting challenge: staying current with an exploding volume of medical literature. Traditional tools like UpToDate, long considered the gold standard for clinical reference, consist of long-form, peer-reviewed summaries that can be difficult to search for specific, nuanced questions. OpenEvidence addresses this gap by allowing natural language queries that return synthesized, cited answers from top-tier medical journals.
“Everyone is using it. Its growth really has been exponential,” Dr. Anupam Jena, an internal medicine physician at Massachusetts General Hospital and a Harvard professor, told NBC News. Jena is currently analyzing 90 million OpenEvidence queries as part of a research project and noted that 60% of searches relate to clinical decision-making.
Meteoric Growth and Investor Confidence
OpenEvidence’s valuation has skyrocketed from $1 billion in early 2025 to $12 billion by January 2026, following a $250 million Series D round led by Thrive Capital and DST Global. The company has raised approximately $700 million in total funding from prominent investors including Sequoia Capital, Google Ventures, Nvidia, Andreessen Horowitz, and Kleiner Perkins, as Forbes reported.
CEO Daniel Nadler, a Harvard Ph.D. who previously founded Kensho Technologies (sold to S&P Global for $700 million in 2018), owns approximately 58% of OpenEvidence, making his stake worth an estimated $7.6 billion. Co-founder Zachary Ziegler holds a 7.3% stake valued at $875 million.
The startup crossed $100 million in annualized revenue in 2025, CNBC reported. Unlike most healthcare software, OpenEvidence is free for physicians, generating revenue through advertising from pharmaceutical and medical device companies.
How It Works
OpenEvidence has secured licensing agreements with the world’s most prestigious medical journals, including the New England Journal of Medicine (NEJM), JAMA Network, and specialized organizations such as the National Comprehensive Cancer Network and the American Diabetes Association. The company says its AI acts as “search glue,” pulling answers directly from licensed full-text content rather than generating responses from unverified internet data.
“We think of AI as search glue. We have access to all of our partners’ full text, to all of their figures. We don’t need the AI to generate answers,” Nadler said in an interview with NBC News.
The platform achieved a perfect score on the United States Medical Licensing Examination (USMLE) in 2025 and has been HIPAA-compliant since April 2024, allowing doctors to input protected health information securely.
Enterprise Adoption and the Mount Sinai Partnership
In a significant step toward institutional adoption, Mount Sinai Health System announced an enterprise partnership with OpenEvidence in March 2026, integrating the platform directly into its Epic electronic health record portal. As Hit Consultant reported, this marked the first enterprise-scale deployment extending access beyond physicians to nurses and pharmacists.
Dr. Girish Nadkarni, head of AI at Mount Sinai, described the phenomenon of “shadow AI” — doctors using tools on personal devices without official approval — and argued that bringing AI tools into the open is essential. “I think it’s time to bring tools like OpenEvidence to the surface,” he told NBC News.
Cautious Optimism and Open Questions
While many doctors praise OpenEvidence — infectious disease specialist Dr. Paul Sax of Brigham and Women’s Hospital told NBC News it “often borders on miraculous” — concerns remain. An academic study released in December, which has not yet been peer-reviewed, found that OpenEvidence accurately answered complex medical questions less than 45% of the time.
Some experts worry that reliance on AI could erode critical thinking skills among medical students and junior doctors. Dr. Hannah Galvin, a pediatrician and chief health information officer at Cambridge Health Alliance, noted that while the tool has improved significantly, “we have concerns over how it is being used to deliver clinical care.”
Competitive Landscape
OpenEvidence faces growing competition. UpToDate is rushing to implement its own AI tool called Expert AI, with approximately 2,000 hospitals and health systems signed up as of April. OpenAI launched “ChatGPT for Clinicians” in April 2026, though it does not currently license the same top-tier medical journals that OpenEvidence has exclusive access to.
What’s Next
Nadler plans to build an “orchestra” of specialized AI models focused on specific medical domains such as oncology, radiology, and neurology. The company is also expanding its AI notetaking, billing, and visit integration functions. As for an IPO, Nadler has indicated that foundation model companies like OpenAI and Anthropic would likely go public first, with application-layer companies like OpenEvidence following.
Rigorous studies on patient outcomes remain lacking, and questions persist about bias, equity, and the long-term sustainability of the ad-supported model. But for now, OpenEvidence has achieved something remarkable: getting the majority of American doctors to voluntarily adopt a single technology platform.
“We did the hardest thing in the history of American health care,” Nadler said. “We got the majority of American doctors to all voluntarily adopt a single technology platform.”