Internet benefits are not one-size-fits-all: age and trust shape digital wellbeing gains.

Background: Although internet use is widespread, its relationship with subjective wellbeing (SWB) remains complex. While previous studies have noted the role of social interaction, less is known about how age and social trust shape this process. Methods: This study investigates how the frequency of internet use relates to SWB among Chinese adults, focusing on the mediating role of social interaction and the moderating roles of social trust and age. Using data from the 2021 Chinese General Social Survey ( Results: The results indicated that: (1) frequent internet use was positively associated with social interaction; (2) social interaction fully mediated the link between internet use and SWB; (3) the positive relationship between internet use and social interaction was stronger for individuals with higher social trust, but weaker among older adults; and (4) the indirect association of internet use was most significant for younger individuals and those with higher social trust. Discussion: These findings suggest that the potential link to wellbeing depends primarily on social interaction, a pathway that varies by individual trust levels and age. The study points to the need for digital policies that consider these demographic and psychological differences.