In the last three months, 8% of Americans first turned to AI tools such as ChatGPT, Gemini and Claude for health information, rising to 11% of Millennials, although search engines (24%) and healthcare professionals (22%) remain the leading first sources. Understanding symptoms (18%) and researching health conditions (18%) are the most common reasons Americans use AI tools for health-related activities. Over a third (37%) say AI's biggest advantage is being available at any time, while a third (33%) believe AI tools offer no advantages for seeking health information. Among Americans who have used AI for health-related activities in the past three months, other reasons include understanding medical terminology (12%), understanding medication side effects (12%), understanding a diagnosis (11%), interpreting medical test results (11%), and finding lifestyle advice (11%). Gen Z and Millennials are jointly the most likely to use AI to understand symptoms, at 21% each.