Optimal Result:
12 - 22 pmol/L.
T4 (thyroxine) is the predominant hormone produced by the thyroid gland. It is an inactive hormone and is converted into its active form, T3 within cells. Free T4 is the non-bound fraction of the total T4 circulating in the blood.
Lab Results Explained and Tracked
What does it mean if your Free T4 result is too high?
T4 (thyroxine) is the predominant hormone produced by the thyroid gland. It is an inactive hormone that is converted into its active form, T3, within cells. Free T4 refers to the non-bound fraction of the total T4 circulating in the blood.
High T4 Levels:
Causes
- Subclinical hyperthyroidism
- Primary hyperthyroidism
- Thyrotoxicosis
- Damage to the hypothalamus or pituitary gland
- Excessive amounts of thyroid hormone medication
- Smoking
- Chronic inflammation
- Pregnancy
- Medications (amiodarone, iodine, interferon)
- Multinodular goitre
- Toxic nodules in the thyroid
- Excess thyroid hormone therapy
Symptoms
- Weight loss
- Insomnia
- Bulging eyes
- Fatigue
- Irregular menstrual cycle
- Weak muscles
- Palpitations
- Excess sweating
- High blood pressure
- Brittle hair
- Diarrhea
Treatment
- Anti-thyroid thionamide medication like carbimazole and propylthiouracil
- Supplement with lemon balm, bugleweed, carnitine, shankhapushpi
- Increase dietary intake of goitrogenic foods such as broccoli, cabbage, soy, corn, wheat, sweet potatoes, lima beans, and tapioca
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What does it mean if your Free T4 result is too low?
T4 (thyroxine) is the predominant hormone produced by the thyroid gland. It is an inactive hormone and is converted into its active form, T3, within cells. Free T4 refers to the non-bound fraction of the total T4 circulating in the blood.
Low T4 Levels:
Causes
- Overt hypothyroidism
- Depression
- Renal failure
- Medications such as aspirin, lithium, amiodarone, interferon, calcium, iron, aluminum
- Pregnancy (fetal hypothyroidism and abnormal development)
- Oral estrogen, which can result in increased thyroid-binding globulin (TBG), leading to lower bioavailable thyroxine (T4)
Symptoms
- Fatigue
- Weight gain
- Cold sensations
- Joint and muscle pain
- Dry skin or dry thinning hair
- Heavy or irregular menstrual periods
- Fertility problems
- Slowed heart rate
- Depression
Treatment
- Supplement with thyroid hormone therapy (thyroxine, thyroid extract)
- Assess and treat iodine deficiency
- Address toxin buildup (fluoride, bromide, mercury, pesticides)
- Supplement with ginger, black cumin, withania, guggul lipids, fucus, bladderwrack, coleus, bacopa, kelp, iodine, carnitine, magnesium
- Limit goitrogenic foods such as broccoli, cabbage, soy, corn, wheat, sweet potatoes, lima beans, tapioca, swede, millet, and peanuts
- Address underlying causes
- Manage stress
- Stop smoking
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