Low cortisol became a piece of internet shorthand for a calm, unbothered lifestyle, popularised through TikTok and short-form video where creators contrasted it with high-stress, always-on routines. Rather than coming from a single film, song, or viral clip, it spread as a caption and spoken reaction, attached to slow mornings, soft lighting, and deliberately low-effort humour. That flexibility is why it keeps circulating: it can describe a mood, a joke, or a whole aesthetic without needing a backstory, and it fits neatly into reaction edits and lifestyle parodies.