Background: This study aimed to test a model in which Instagram images-based activities related to self, friends, and celebrities were associated with acceptance of cosmetic surgery via Instagram appearance comparison and body dissatisfaction. We predicted that Instagram use for images-related activities involving celebrities and self (but not friends) was associated with acceptance of cosmetic surgery both directly and indirectly. Methods: The study participants were 305 Italian women (mean age, 23 years). They completed a questionnaire containing the Instagram Image Activity Scale, the Instagram Appearance Comparison Scale, the Body Shape Questionnaire-14, the Acceptance of Cosmetic Surgery Scale. A path analysis was performed in which the Instagram images-based activities were posited as predictors of the Instagram appearance comparison, body dissatisfaction and acceptance of cosmetic surgery, respectively. Results: We found that only image-based activities related to celebrities and self were significantly related to acceptance of cosmetic surgery, whereas friends’ Instagram-related activities were not significantly related to this criterion variable. Moreover, the indirect effect of both Instagram self- and celebrities-images activities on acceptance of cosmetic surgery through Instagram appearance comparison and body dissatisfaction was significant. Friends’ Instagram images-related activities were not associated with acceptance of cosmetic surgery. Conclusions: Overall, these findings provide information about the role that activities carried out on Instagram, appearance comparison and body dissatisfaction, play on the acceptance of surgery for aesthetic reasons among women. The study highlighted the importance for surgeons to consider some psychological aspects and the influence of sociocultural factors on the interest for cosmetic surgery. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Perception of mattering, the feeling of being important to others (Rosenberg & McCullogh in Community Ment Health J 2:163–182, 1981), is receiving increasing attention as a factor that promotes well-being. Individual well-being has been defined in different ways, such as hedonic, as in a deep satisfaction with life (Diener & Lucas in Well-being: Foundations of Hedonic Psychology 213, 1999), eudaimonic, as in the realization of the true self (Ryff in Curr Dir Psychol Sci 4(4):99–104, 1995), and holistic, which is satisfaction across all domains of life (Prilleltensky et al., in J Community Psychol 43(2):199–226, 2015). The present study aims to systematize this body of literature on mattering and well-being to clarify whether the two constructs are linked independently from their conceptualization; to this end, a meta-analysis of 30 studies, following the PRISMA framework, was conducted. A significant medium effect size emerged between mattering and well-being (r = 0.41*** [95% CI 0.33, 0.49]), with eudaimonic well-being showing a higher effect size in association with mattering (r = 0.55*** [95% CI 0.46, 0.64]). The results indicate that mattering is a relevant construct when studying the positive functioning of individuals; in particular, mattering was found to be a key factor in the process of defining one’s sense of worth and purpose in life.