Thyroid Stimulating Hormone (TSH) Levels
Your individual optimal TSH is often narrower than the lab reference range. Someone who feels best at 1.0 will feel terrible at 3.5—even though both are "normal." Knowing your sweet spot ends years of being told "you're fine" when you're clearly not.
What this measures
How your DNA shapes thyroid stimulating hormone (TSH) levels.
TSH levels depend on the feedback loop between brain (hypothalamus, pituitary) and thyroid. TSHR (the TSH receptor on the thyroid), PDE8B (which regulates the cAMP signaling downstream of TSH), and TPO (thyroid peroxidase, which makes thyroid hormone) all shape baseline TSH set-point. Different people's "normal" TSH genuinely sits at different values.
Carriers of common PDE8B variants are associated with higher baseline TSH at any given level of thyroid hormone production — which can make their "normal" TSH look high even when free T4 and T3 are adequate. Carriers of TSHR variants are associated with altered TSH-thyroid signaling. The variants explain why some carriers feel best at TSH 1.0 and others at TSH 2.5.
Iodine is the essential substrate. Selenium supports TPO function. Adequate iron, zinc, and vitamin D all influence thyroid hormone production. Severe caloric restriction, chronic stress, and certain medications (lithium, amiodarone) all alter TSH. Bedtime estrogen exposure (in hormone replacement) raises TSH transiently.
A TSH of 3.5 isn't the same number across clients. Which PDE8B/TSHR/TPO variant pattern you carry decides whether your "in range" TSH actually feels good or whether a slightly lower or higher number is the better personal target — a conversation worth having with a thyroid-aware clinician.
Thyroid Stimulating Hormone (TSH) Levels is one specific finding in this system. Your Genomic Lifestyle Optimization Report shows where your variants place you on the hormones spectrum — and what you can do about it: it renders as a dark card with a color marker calibrated to your variants, opening with the gene mechanism and closing with a practical, mechanism-led recommendation.
Want to see what a real Mosaic dark card looks like? Walk through a sample report →
In context
Thyroid: the 4-insight cluster.
Thyroid Stimulating Hormone (TSH) Levels is one finding in a tightly-related cluster. Mosaic sequences the other 3 alongside it so you see the whole biology — not an isolated data point.
Questions people ask
About Thyroid Stimulating Hormone (TSH) Levels.
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