Understanding TSH: Normal vs Optimal Ranges

?What is TSH?

TSH (thyroid stimulating hormone) is produced by the pituitary gland to regulate thyroid hormone production. When thyroid hormones (T4 and T3) are low, TSH rises to stimulate more production; when thyroid hormones are high, TSH falls. TSH is the single best screening test for thyroid function and is the most sensitive marker for early thyroid disease.

!Why It Matters

Subclinical hypothyroidism (elevated TSH with normal T4) affects up to 10% of adults and is associated with elevated cholesterol, cardiovascular disease risk, fatigue, and mood disturbances. Subclinical hyperthyroidism (low TSH) increases risk of atrial fibrillation and osteoporosis. TSH is the master regulator of thyroid function — even small deviations from optimal are clinically relevant.

Reference Ranges

Lab normal ranges may vary between laboratories. Optimal and longevity targets are based on research literature and should be interpreted with your physician.

Symptoms of Imbalance

• High TSH (hypothyroidism): fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, brain fog, depression
• Low TSH (hyperthyroidism): weight loss, heat intolerance, palpitations, tremor, anxiety, insomnia, diarrhoea

How to Improve Your Levels

• 1If TSH is elevated: ensure adequate iodine intake (iodised salt), selenium (Brazil nuts), and zinc
• 2Avoid goitrogenic foods in excess (raw cruciferous vegetables) if iodine-deficient
• 3Manage stress — chronic stress suppresses thyroid function
• 4Optimise vitamin D and iron — both support thyroid hormone production
• 5Levothyroxine is the standard treatment for hypothyroidism — do not stop without medical advice

When to Test

Screen all adults every 3–5 years, or annually if you have risk factors (family history, autoimmune conditions, neck radiation). Women planning pregnancy or in first trimester should be screened. Always fast before thyroid tests and take medication (if any) after blood draw.

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