Every winter, TSH rises—but that doesn't mean thyroid failure. Dr Eric Balcavage explains how photoperiod, melatonin, and circannual rhythms alter TRH → TSH → T3 and why seasonal adaptation is often misdiagnosed as hypothyroidism. In this episode, you'll learn: ✅ How shorter days and colder temperatures reset the hypothalamic–pituitary–thyroid axis ✅ Why macro-TSH raises lab TSH without true hypothyroidism ✅ How both conventional and functional models misread winter physiology ✅ Five ways to align with your seasonal thyroid rhythm (light, rest, minerals, movement, patience)