I am surprised to see that there is significant relationship between hyperthyroidism and POIS.I am diagnosed with hyperthyroidism. My blood test show that I have low level of TSH and high level of T4. I am taking PTU which is the only treatment available in Ethiopia. I have seen one discussion in this platform the correlation between hypothyroidism and POIS based on one of the member experience. It is believed that activated mast cells can contribute to the development of both hypo/hyperthyroidism by releasing inflammatory mediators like histamine, potentially influencing thyroid hormone production. Mast cells are present within the thyroid gland and can be activated by various stimuli, including autoimmune reactions targeting thyroid tissue It is very depressing to know that Addressing POIS is mandatory for the POSER like me to get lasting treatment from hyperthyroidism.