Gemini Answers 77.1% of Health Questions Without Citing a Source vs 2.4% for ChatGPT

Gemini gives no source at all in 77.1% of its answers to health questions, against 2.4% for ChatGPT. When AI answers do cite, the National Institutes of Health dominates: nih.gov appears in 32.3% of sourced health answers, three times the rate of the next website, the CDC.

All answers by rank

32.3%

10.6%

7.7%

7.1%

5.3%

5.2%

4.9%

4.5%

4.1%

3.4%

2.8%

2.4%

2.3%

Source: Suff Digital analysis of 1,600 AI answers to 400 health questions · ChatGPT and Gemini, September 2026

ChatGPT

Answers with no source

2.4%

Share of sourced answers citing it

38.3%

Source: Suff Digital analysis of 1,600 AI answers to 400 health questions · ChatGPT and Gemini, September 2026

Share of sourced answers by industry

Health

32.3%

Fitness

41.5%

Recipes

37.5%

Real estate

27.2%

Software

24.3%

Pets

18.4%

Legal

14.7%

Money

13.8%

Travel

13.2%

College

13.1%

Home improvement

11.8%

Cars

6.7%

Source: Suff Digital analysis of 1,600 AI answers to 400 health questions · ChatGPT and Gemini, September 2026

Source: Gemini Answers 77.1% of Health Questions Without Citing a Source vs 2.4% for ChatGPT - Suff Digital