TSH

Thyroid-Stimulating Hormone (TSH), produced by the pituitary gland, regulates thyroid hormone production. High TSH suggests hypothyroidism (underactive thyroid), while low TSH suggests hyperthyroidism (overactive thyroid). While standard ranges are broad (e.g., ~0.4-4.5 mIU/L), many longevity and functional medicine experts advocate for a narrower optimal range for better overall well-being, even in the absence of overt disease. Note: In elderly individuals (e.g., >70-80 years old), TSH may naturally be slightly higher (e.g., up to 5-7 mIU/L) without necessarily indicating pathology or requiring treatment.