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Thyroid medications require a prescription and regular monitoring. Incorrect dosing can cause serious complications including heart problems, bone loss, and more. NEVER adjust thyroid medication doses without your doctor's guidance.
Educational reference for understanding thyroid hormone dosing
Normal range: ~0.4-4.5 mIU/L (varies by lab)
| Medication | Type | Half-Life | Key Notes |
|---|---|---|---|
| Levothyroxine Synthroid, Levoxyl, Tirosint, etc. | Synthetic T4 | ~7 days | Standard treatment. Take on empty stomach. Body converts T4→T3 as needed. |
| Liothyronine Cytomel | Synthetic T3 | ~1 day | Fast-acting. Sometimes added to T4. Requires 2-3 daily doses. More cardiac effects. |
| Armour Thyroid / NP Thyroid | Desiccated T4+T3 | Variable | Natural, from pig thyroid. Contains both hormones. Some patients prefer; not first-line. |
| Tirosint | Synthetic T4 (liquid gel) | ~7 days | Better absorption for those with GI issues or on PPIs. More expensive. |
Contact your doctor if these develop—dose may need to be reduced.
If symptoms persist despite treatment, TSH may need rechecking.
Food, especially fiber, calcium, and iron, significantly reduces levothyroxine absorption. Taking it on an empty stomach with water ensures consistent absorption. Some people take it at bedtime (at least 3 hours after eating) if morning dosing is difficult.
Usually no. Most hypothyroidism is permanent (Hashimoto's, post-thyroidectomy, post-RAI). Stopping medication will cause your TSH to rise and symptoms to return within weeks. Some people with transient hypothyroidism (postpartum, subacute thyroiditis) may eventually stop, but only under medical supervision with monitoring.
Several reasons: Your "optimal" TSH may be different from average normal. Non-thyroid causes of fatigue and other symptoms are common (iron deficiency, sleep apnea, depression). Some people feel better with TSH in the lower-normal range. Discuss with your doctor about fine-tuning your dose.
Not necessarily. Most endocrinologists prefer levothyroxine because the dose is precise and consistent. Desiccated thyroid (Armour) has variable T4:T3 ratios between batches. Some patients feel better on it, possibly due to the added T3. There's no strong evidence it's superior for most.
Because levothyroxine has a long half-life (~7 days), missing one dose is rarely a problem. Take it when you remember, unless it's almost time for your next dose. Some people take both doses together the next day if they completely forget. Don't make a habit of missing doses.
Pregnancy increases thyroid hormone demands by 25-50%. This starts early in the first trimester. Inadequate thyroid hormone can affect fetal brain development. TSH should be monitored every 4 weeks during the first half of pregnancy, and your dose adjusted as needed.