Ad-driven medical AI company OpenEvidence valued at $15B, used by nearly two-thirds of US doctors

Founded by Daniel Nadler in 2022, OpenEvidence processed over 42 million prompts from US doctors last month and is valued at $15 billion. It has raised nearly $1 billion in the past 18 months, signed $100 million in ad commitments by end-2025, and expects $400-500 million in ad revenue by end-2026. Its core pitch is retrieving only peer-reviewed journals and clinical guidelines such as NEJM and JAMA, and it is embedded in EHRs at Mount Sinai, Memorial Sloan Kettering and others. For hospital IT and clinicians, this means a tool adopted by doctors themselves, bypassing hospital procurement, is entering clinical decision-making; NYU Langone chose to formally integrate its clinical version to control safety boundaries. But a small Mayo Clinic study found its recommendations, while accurate, had limited impact on treatment decisions, and a June Nature paper found it underperformed general models like Gemini and GPT on clinical benchmarks. For medical AI product teams, OpenEvidence exited the EU and UK this year over the EU AI Act, showing compliance costs directly limit expansion paths. Meanwhile OpenAI's ChatGPT health version and Anthropic's medical tools are entering the same space, and Anthropic has partnered with OpenEvidence to bring tools to 100 low- and middle-income countries.