The literature on body image ramifications of girls’ uses of appearance-focused social media (ASM) is limited, and even non-existing in terms of TikTok uses. With this brief report, we aimed to fill this gap in the literature by analyzing three waves of data on girls’ ASM use and body image-related constructs (i.e., internalization of beauty ideals and body image self-discrepancy) using random-intercept cross-lagged panel models (RI-CLPMs). The total sample consisted of 229 girls (M_age = 15.12, SD = 1.50). Controlling for age and body mass index (BMI), the RI-CLPMs revealed that neither TikTok nor Instagram were predictive of subsequent increases or decreases in internalization of beauty ideals and body image self-discrepancy. Lower scores on body image self-discrepancy at W2 (i.e., wanting to have a thinner body) did predict higher uses of Instagram at W3. No evidence for between-person effects was garnered. The results enrich our knowledge on long-term implications of girls’ Instagram and TikTok use for their body image. They further underline the need for research that more specifically disentangles the role of different appearance-related activities on social media and their impact on girls’ body image constructs.

关于女孩使用以外表为中心的社交媒体 (ASM) 的身体形象后果的文献是有限的，甚至在 TikTok 使用方面不存在。通过这份简短的报告，我们旨在通过使用随机截距交叉分析关于女孩 ASM 使用和身体形象相关结构（即美丽理想的内化和身体形象自我差异）的三波数据来填补文献中的空白滞后面板模型（RI-CLPM）。总样本由 229 名女孩组成（M_年龄= 15.12，SD= 1.50)。控制年龄和体重指数（BMI）后，RI-CLPM 显示，无论是 TikTok 还是 Instagram，都无法预测美丽理想的内在化和身体形象自我差异的后续增加或减少。W2 的身体形象自我差异得分较低（即希望拥有更瘦的身体）确实预示着 W3 对 Instagram 的更多使用。没有获得人与人之间影响的证据。这些结果丰富了我们对女孩使用 Instagram 和 TikTok 对其身体形象的长期影响的认识。他们进一步强调需要进行更具体的研究，以解开不同外表相关活动在社交媒体上的作用及其对女孩身体形象结构的影响。