Social media influencers (SMIs) who publish content on mental health play a vital role in the lives of teenage girls. To examine what kind of mental health advice SMIs give, we interviewed teenage girls and identified SMIs that regularly post content on mental health. The indexing of their YouTube videos (n=234) shows that the advice includes calls to self-improvement; work on the body; and seeking help. Our analysis demonstrates that working strategically to uphold their fame, the SMIs balance the roles of expert and friend; turn consumption into mental health advice; and gain legitimacy via collaborations with health organisations. The logic specific to social media requires an additional layer in the interpretation of mental health content in SMI videos. While reciprocity and support between SMI and follower are enabled, the inclusion of such content is also strategically beneficial for the SMI as it contributes to increase her perceived authenticity.