Possible Causes | Effect on Thyroid Hormones | Notes |
---|---|---|
Acute or Chronic Dieting | Decrease intracellular T3 levels up to 50% Decrease Basal Metabolic Rate by 15-40% |
With chronic dieting, thyroid levels and metabolism may not recover. |
Inflammation | Conversion from T4 to T3 Decreased Intracellular T3 |
Inflammatory cytokines are high (IL-1, IL-6, CRP>3mg/l, TNF-alpha) |
Insulin Resistance (Diabetes) | Conversion from T4 to T3 decreases (45%) Decreased Intracellular T3 Increase in rT3 (inactive T3) |
Normal Individual converts appx 77% of T4 to T3 Also suppresses Testosterone levels |
Obesity & Leptin Resistance | Low Intracellular T3 | Leptin >10 demonstrates low Intracellular T3 |
Greater than moderate exercise | Reduced T4 to T3 conversion Increased rT3 (inactive T3) |
|
Iron Deficiency | Reduced T4 to T3 conversion Increased rT3 (inactive T3) |
A ferritin < 70 will result in diminished intracellular T3 |
Low Vitamin D3 | May need levels in range of 50-70ng/mL | |
Low B Vitamins (B1, B3, B6) & Vitamin C | Slows the conversion of T4 to T3 | Important for T4 to T3 conversion |
Low Minerals (Copper, Zinc & Selenium) | Slows the conversion of T4 to T3 | Copper & Zinc are important for T4 to T3 conversion |
Toxic Liver | Slows the conversion of T4 to T3 | |
Stress | Conversion to rT3 (Inactive T3) Slows conversion of T4 to T3 |
Adrenal fatigue can result in slowed conversion of T4 to T3 |
Environmental Toxins [Pesticides, plastics, heavy metals (mercury and cadmium), etc.] | Reduce conversion of T4 to T3 | BPA from plastics, Mercury from fish, Cadmium, Halogens may be sources of toxicity |
Goitrogens | Decrease Iodine and thyroid production | Need to cook Cabbage, Kale, Turnips, Radish |
- T4 SR capsules: 20mcg, 40mcg, and other custom strengths
- T3 SR capsules: 0.25mcg, 0.5mg, 1mcg, 1.5mcg, 2mcg, 2.5mcg, 3mcg, 4mcg, 5mcg, 10mcg, 15mcg, 20mcg, 25mcg, 30mcg, 40mcg, 50mcg, 100mcg, and other custom strengths
- T4/T3 SR capsules: 9.5/2.25mcg, 19/4.5mcg, 38/9mcg, 47.5/11.25mcg, 57/13.5mcg, 76/18mcg, 85.5/20.25mcg, 95/22.5mcg, 114/27mcg, 152/36mcg, 190/45mcg, and other custom strengths
- Armour Thyroid tablets: 15mg, 30mg, 60mg, 90mg, 120mg, 180mg
- Nature-Throid tablets: 16.25mg, 32.5mg, 48.75mg, 65mg, 81.25mg, 97.5mg, 113.75mg, 130mg, 146.25mg, 162.5mg, 195mg
- West-Throid Pure (WP) tablets: 16.25mg, 32.5mg, 48.75mg, 65mg, 81.25mg, 97.5mg, 113.75mg, 130mg