GPT-5.5 Instant

Trends

• Clinical AI evidence moves to peer-reviewed, physician-validated reasoning

Items

1. Jun 18

   GPT-5.5 Instant brings frontier health answers to ChatGPT

   The free model now matches OpenAI's Thinking models on HealthBench Professional and other evaluations built with 260+ physicians in 60 countries, improving urgent-care recognition and uncertainty handling for the 230M+ people asking ChatGPT health questions weekly.

2. May 5

   OpenAI's GPT-5.5 Instant

   The new ChatGPT default for all users makes 52.5% fewer hallucinated claims than GPT-5.3 Instant on high-stakes medical, legal, and financial prompts, and adds personalization from past chats, files, and Gmail with new memory sources showing which context shaped each answer.