OpenAI has upgraded ChatGPT's healthcare capabilities with the GPT-5.5 Instant model. The updated model matches the performance of the most expensive Thinking models on machine-based health tests like HealthBench and HealthBench Professional, but at a fraction of the cost. GPT-5.5 Instant is available to all free ChatGPT users, though with usage limits.
When compared to doctors, GPT-5.5 Instant's responses scored higher in accuracy, clarity, and completeness. The rate of incorrect health statements has dropped by 71 percent over the past two months.
GPT-5.5 Instant tops both GPT-4o and physician-written answers across all five evaluation categories in OpenAI's own benchmarks, scoring up to 89.9 percent on instruction following. | Image: OpenAI
A network of over 260 doctors from 60 countries is behind these improvements. They've reviewed more than 700,000 model responses. According to OpenAI, more than 230 million people use ChatGPT weekly for health-related questions, things like understanding lab results, prepping for doctor's appointments, or sorting out insurance questions. OpenAI also offers specialized tools for healthcare professionals, including ChatGPT for Clinicians and OpenAI for Healthcare.
