Free T4
Free T4 is the primary hormone produced by the thyroid gland. It serves as a precursor to Free T3, the active thyroid hormone, and plays an important role in regulating metabolism, energy production, body temperature, and overall cellular function.
Sample Type
ARM BLOOD
Fast results
3 DAYS
What is Free T4?
Free T4 provides insight into how much thyroid hormone is being produced and released by the thyroid gland. Often described as the body's reserve form of thyroid hormone, Free T4 circulates through the bloodstream and is converted into Free T3, the active hormone used by cells throughout the body. Together, these hormones help regulate metabolism, energy production, cognitive function, cardiovascular health, and many other essential processes.
Because thyroid hormones influence nearly every organ system, even subtle changes may affect how you feel and perform.
Monitoring Free T4 can help provide valuable information about thyroid function and overall metabolic health. Tracking trends over time may help identify changes related to aging, stress, lifestyle factors, and overall hormonal balance.
Symptoms of Imbalanced Free T4
Low or high levels may show up in many ways.
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Fatigue
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Weight issues
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Dry skin
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Reduced exercise performance
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Difficulty concentrating
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Increased sensitivity to cold
Frequently paired with:
TSH
You may also consider:
Free T3
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A personalized health membership that gives you access to one biomarker test each month.
Monitor key aspects of your health from home with convenient saliva collection or a painless arm blood collection device, professional laboratory analysis, easy-to-understand results and ongoing support.
How does the membership work?
Each month, you'll receive one Test Credit. Simply log into your ALYX dashboard, choose the biomarker you'd like to test, and we'll ship your at-home collection kit directly to your door. Complete your sample and receive secure digital results in just a few days.
Can I skip or cancel anytime?
Yes. You can skip a month, pause your membership, or cancel anytime through your account. There are no long-term commitments or cancellation fees.
Is this covered by insurance?
ALYX is a direct to consumer wellness membership designed to provide affordable, convenient access to biomarker testing without the need for insurance, expensive copays or deductibles, or a doctor's visit.
While ALYX does not bill insurance directly, we can provide an itemized receipt that you may submit to your insurance provider for possible reimbursement. Reimbursement is subject to your individual insurance plan and benefits.