A significant amount of appearance-based content is available for consumption on social media sites such as Instagram, TikTok and YouTube. Imagery that depicts idealized appearances is pervasive on these sites and has been shown to have detrimental consequences for body image and related outcomes. Whilst efforts have been made to challenge beauty ideals via online body positive movements, social media 'influencers', also known as 'content creators,' continue to disseminate content that reflects beauty ideals and is commercially endorsed to their large following. This paper aims to consolidate what is known about beauty, fashion, and lifestyle influencers, including 'body positive' influencers, and the effects of their content on followers. It also endeavors to identify gaps in the literature, proposing important considerations for future research including the potential impact of various influencer, follower, and platform-based factors on body image. Understanding influencers' social media experiences and their attitudes towards different appearance-based content can inform future body image protection strategies made by social media platforms, agencies, brands, policymakers, influencers and their followers.