Evidence check: TSH Schilddrüse in the context of Haut

TSH (thyroid-stimulating hormone) is a key regulator of thyroid function. Altered TSH levels can indicate hypothyroidism or hyperthyroidism, both of which affect the skin: hypothyroidism often causes dry, rough skin, cold intolerance, and myxedema; hyperthyroidism leads to warm, moist, thin skin. However, TSH itself is not a direct skin biomarker. The evidence linking TSH to skin health comes from clinical observations in thyroid disease, not from studies validating TSH as a predictor of skin conditions in healthy individuals. Consumer lab tests measuring TSH can provide clues about thyroid dysfunction but must be interpreted by a physician – especially because TSH fluctuates with circadian rhythm, stress, and medications. An isolated TSH value without T3/T4 and clinical symptoms is insufficient for skin assessment. The evidence is moderate: the mechanistic and clinical link is well-established, but TSH is not validated as a direct skin marker. Safety note: self-medicating with thyroid hormones or iodine based on TSH results is dangerous and can cause thyrotoxicosis.