During autumn (and spring), when temperatures fluctuate, the thyroid gland has to work harder, and people with thyroid issues may experience mood swings and a lack of energy for a few weeks during these periods. Thyroid hormones require approximately seven days, which is the half-life of thyroid hormones, to adjust the metabolism to temperature changes.
However, when temperatures vary significantly from day to day, the thyroid can struggle to adapt to the external conditions. This can negatively affect mood, body temperature, energy levels, and even the immune system. It is essential for the thyroid to have sufficient levels of the right nutrients to function optimally: selenium, zinc, copper, manganese, L-tyrosine, iodine, vitamin C, and vitamin B6.
A good multivitamin can help provide most of these nutrients. Additional support with iodine can also be important. Chris Kresser, who works in integrative medicine in the USA and has written extensively about hypothyroidism, states that 80% of his hypothyroid patients are iodine deficient. Dr. David Brownstein reports that after testing over 500 patients, he found that 94.7% of them were iodine deficient.
Read more about the thyroid here