Hashimoto’s and Graves’ Disease Autoimmune thyroid disorders occur when the body’s immune system mistakenly attacks the thyroid gland, disrupting its ability to function normally. Two of the most common autoimmune thyroid conditions are Hashimoto’s thyroiditis and Graves’ disease. Though they both involve immune dysfunction, they affect the thyroid in opposite ways. Hashimoto’s Thyroiditis (Underactive Thyroid) What it is: Hashimoto’s thyroiditis is the most common cause of hypothyroidism (an underactive thyroid). In this condition, the immune system attacks the thyroid tissue, gradually damaging it and reducing its ability to produce thyroid hormones. Key Symptoms: Chronic fatigue Weight gain Cold intolerance Constipation Dry skin Depression Hair thinning Brain fog Irregular or heavy periods Enlarged thyroid (goiter) Who’s at risk: Women (especially aged 30–50) Those with a family history of autoimmune disorders People with other autoimmune diseases, like Type 1 diabetes or celia...