Your circadian rhythm (aka your sleep-wake cycle) runs the show + has more of an impact on your hormones than you might realize. It's governed by a master clock in the hypothalamus called the suprachiasmatic nucleus (SCN). This clock controls everything from wakefulness and sleep to hunger cues, growth-hormone release, metabolism, body temperature, and even how well your hormones sync. The biggest cue that sets this clock? LIGHT. Sunlight, moonlight, and yes... the endless blue-light glow of our screens. But here's the part most people don't realize: Your circadian rhythm is one of the biggest regulators of your entire hormone system. It influences cortisol, insulin, thyroid hormones, appetite hormones, reproductive hormones... truly everything. When your sleep-wake cycle is aligned, your hormones have structure, rhythm, and predictability.