To better support older adults' consumption of high quality health information on the Internet, it is important to understand how older adults make credibility judgments with online health information. For this purpose, we conducted two laboratory studies to explore how the credibility cues in message contents, website features, and user reviews could differentially impact younger and older adults' credibility judgments. Results from the first experiment showed that older adults, compared to younger ones, were less sensitive to the credibility cues in message contents, as well as those in the website features. Results from the second experiment showed that user reviews that were consistent with the credibility cues in message contents could reinforce older adults' credibility judgments. Older adults, compared to younger adults, seemed to be less swayed by user reviews that were inconsistent with the message contents. These results provided implications for designing health information websites that better support older adults' credibility judgments.