What It Measures
TSH measures the level of thyroid-stimulating hormone in the blood, which reflects how hard the pituitary gland is working to stimulate the thyroid. High TSH means the pituitary is signaling the thyroid to produce more hormones (suggesting underactive thyroid), while low TSH means the pituitary is backing off (suggesting overactive thyroid or adequate hormone levels).
Thyroid-stimulating hormone (TSH) is produced by the anterior pituitary gland and regulates the thyroid gland's production of T3 and T4. It is the most sensitive marker for detecting thyroid dysfunction and is typically the first test ordered when thyroid disease is suspected.
Current Value
What High Means
Elevated TSH (hypothyroidism) indicates the thyroid is underproducing hormones, prompting the pituitary to increase stimulation. Causes include Hashimoto's thyroiditis (autoimmune), iodine deficiency, thyroid surgery/radiation, certain medications (lithium, amiodarone), and pituitary tumors (rare). Subclinical hypothyroidism (TSH 4.5-10 mIU/L with normal T4) is associated with increased cardiovascular risk, elevated cholesterol, and progression to overt hypothyroidism at ~2-5% per year.
Possible Symptoms
Fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, brain fog, depression, muscle weakness, elevated cholesterol, puffy face, hoarse voice, irregular or heavy menstrual periods, slow heart rate
What Low Means
Low TSH (hyperthyroidism) indicates excess thyroid hormone production, causing the pituitary to reduce TSH secretion. Causes include Graves' disease (autoimmune), toxic multinodular goiter, thyroiditis, excessive thyroid medication, and rarely pituitary dysfunction (central hypothyroidism where low TSH paradoxically accompanies low T4). Suppressed TSH is associated with atrial fibrillation, osteoporosis, and anxiety disorders.
Possible Symptoms
Anxiety, irritability, rapid heartbeat, tremors, weight loss, heat intolerance, increased sweating, frequent bowel movements, insomnia, muscle weakness, eye bulging (Graves'), irregular menstrual periods, osteoporosis risk
Risk Factors
Hashimoto's thyroiditis, Graves' disease, thyroid nodules, goiter, cardiovascular disease, hypercholesterolemia, type 2 diabetes, infertility, depression, osteoporosis, atrial fibrillation, pregnancy complications (miscarriage, preeclampsia), obesity, adrenal dysfunction
Actionable Advice
Supplements
- •Selenium (200mcg)
- •Zinc (15-30mg)
- •Iodine (150-300mcg from kelp/seaweed)
- •Vitamin D3
- •Ashwagandha (for hypothyroid support)
- •B-complex vitamins
- •Iron (if deficient)
- •Magnesium glycinate
- •Omega-3 fatty acids
- •L-tyrosine
Diet & Lifestyle
- •Manage stress through meditation, yoga, or breathwork — chronic cortisol disrupts the HPT axis
- •Sleep 7-9 hours consistently; sleep deprivation raises TSH
- •Avoid excessive cruciferous vegetables raw if hypothyroid (cooking reduces goitrogens)
- •Limit processed soy products which can interfere with thyroid hormone absorption
- •Exercise regularly but avoid overtraining which can suppress thyroid function
- •Reduce exposure to endocrine disruptors (BPA, phthalates, fluoride, perchlorate)
- •Take thyroid medication (if any) on an empty stomach, 30-60 min before food
- •Ensure adequate protein intake — tyrosine from protein is a thyroid hormone precursor
- •Limit gluten if you have Hashimoto's — gluten molecular mimicry may trigger thyroid antibodies
- •Get tested for thyroid antibodies (TPO, TgAb) to rule out autoimmune thyroiditis
Ask AI
Ask questions about your TSH results, trends, and what you can do to optimize.
Historical Trend
Related Biomarkers
Resources & Studies
All Readings
| Date | Value | Change |
|---|---|---|
| 2026-01-28 | 0.85 mIU/L | 0.0 |
| 2025-08-25 | 0.85 mIU/L | -0.2 |
| 2025-06-27 | 1.029 mIU/L | — |