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How your thyroid works
What your thyroid does, how it turns T4 into active T3, the signs it may be running slow or fast, and why a full thyroid panel can show more than a TSH test alone.
Your thyroid is a small gland at the front of your neck, and it plays a big part in keeping your hormones in balance. It works closely with other glands in your body, including your ovaries or testes, your adrenals and your pancreas.
How it works
The pituitary gland in your brain sends your thyroid a message called TSH (thyroid stimulating hormone). This tells your thyroid to make T4, an inactive form of thyroid hormone. Your body then converts T4 into T3, the active form. T3 helps set your metabolism and weight, energy, body temperature, memory and focus, mood, digestion, skin and hair, and your cycle and fertility.
What helps T4 become T3
This conversion relies on nutrients such as iodine, selenium, zinc, iron, magnesium and vitamin D. Most of it happens in your liver, and some in your gut, so how well these are working matters too. Stress, inflammation, infection, digestive issues or low nutrient levels can turn more T4 into reverse T3, an inactive form that can block T3 from doing its job.
Signs your thyroid may be running slow
An underactive thyroid (hypothyroidism) can show up as weight gain or trouble losing weight, fluid retention or puffiness, tiredness, constipation, changes to your cycle or trouble falling pregnant, brain fog or poor memory, feeling cold, anxiety or low mood, aches and pains, dry skin and hair, acne, hair loss, or thinning at the outer edge of your eyebrows.
Signs it may be running fast
Less often, the thyroid makes too much hormone (hyperthyroidism). This can cause a racing or pounding heart, weight loss without trying, anxiety and, in some people, eyes that bulge forward.
Testing your thyroid
A standard thyroid check usually starts with TSH. A full thyroid panel also looks at markers such as free T4, free T3, reverse T3 and thyroid antibodies. Together they give a fuller picture, including levels that are in the normal range but may not be ideal for you. Medicare doesn't always cover these extra markers.
If any of this sounds familiar, a practitioner can talk it through with you and help you decide whether testing makes sense. If your symptoms are new, severe or getting worse quickly, please see your GP.
How it works
The pituitary gland in your brain sends your thyroid a message called TSH (thyroid stimulating hormone). This tells your thyroid to make T4, an inactive form of thyroid hormone. Your body then converts T4 into T3, the active form. T3 helps set your metabolism and weight, energy, body temperature, memory and focus, mood, digestion, skin and hair, and your cycle and fertility.
What helps T4 become T3
This conversion relies on nutrients such as iodine, selenium, zinc, iron, magnesium and vitamin D. Most of it happens in your liver, and some in your gut, so how well these are working matters too. Stress, inflammation, infection, digestive issues or low nutrient levels can turn more T4 into reverse T3, an inactive form that can block T3 from doing its job.
Signs your thyroid may be running slow
An underactive thyroid (hypothyroidism) can show up as weight gain or trouble losing weight, fluid retention or puffiness, tiredness, constipation, changes to your cycle or trouble falling pregnant, brain fog or poor memory, feeling cold, anxiety or low mood, aches and pains, dry skin and hair, acne, hair loss, or thinning at the outer edge of your eyebrows.
Signs it may be running fast
Less often, the thyroid makes too much hormone (hyperthyroidism). This can cause a racing or pounding heart, weight loss without trying, anxiety and, in some people, eyes that bulge forward.
Testing your thyroid
A standard thyroid check usually starts with TSH. A full thyroid panel also looks at markers such as free T4, free T3, reverse T3 and thyroid antibodies. Together they give a fuller picture, including levels that are in the normal range but may not be ideal for you. Medicare doesn't always cover these extra markers.
If any of this sounds familiar, a practitioner can talk it through with you and help you decide whether testing makes sense. If your symptoms are new, severe or getting worse quickly, please see your GP.
This video is general information, not advice about your own health. A practitioner can talk you through what it means for you.
The test in this video
Every test includes a video consult with the practitioner to go through your results.
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