Levothyroxine is a synthetic version of the thyroid hormone thyroxine (T4) that is used to treat hypothyroidism, an underactive thyroid gland. Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormones to meet the body’s needs. Levothyroxine replaces the T4 that your own thyroid gland cannot produce and returns thyroid hormone to normal levels in the body. This helps relieve symptoms of hypothyroidism and prevent complications.
For levothyroxine to work properly, it needs to be effectively absorbed from the gastrointestinal tract into the bloodstream. However, some factors can impair the absorption of levothyroxine in certain people. When levothyroxine is not well absorbed, blood levels can remain low or fluctuate, causing hypothyroid symptoms to persist.
The good news is that there are several ways you can optimize levothyroxine absorption. Here are some helpful tips:
Take levothyroxine consistently on an empty stomach
Levothyroxine should be taken on an empty stomach. Food, beverages, and even some medications can impair levothyroxine absorption when taken at the same time.
Take your levothyroxine first thing in the morning at least 30-60 minutes before eating breakfast. Be consistent and try to take it at the same time each day. Avoid coffee, juice, or other beverages besides water in the morning before taking your levothyroxine. The same empty stomach guidelines apply if you take levothyroxine before bedtime.
Set a reminder alarm on your phone or keep your levothyroxine next to the coffeemaker as a visual cue to remember to take it before eating or drinking anything besides water. Taking it consistently on an empty stomach allows for optimal absorption.
Avoid interfering medications, supplements, and foods
Certain medications, supplements, and even some foods can interfere with levothyroxine absorption when taken at the same time. These include:
- Calcium and iron supplements
- Antacids
- Sucralfate
- Cholestyramine
- Colestipol
- Orlistat
- Raloxifene
- Soy products
- Fiber supplements
- Whole wheat bread
- Walnuts
To prevent issues, take your levothyroxine at least 4 hours before or after any interacting medications, supplements, or foods. For example, if you take your levothyroxine at 7 am, wait until at least 11 am to take any calcium or iron supplements. If possible, take these interacting products at night, the farthest time away from your levothyroxine dose.
Split up calcium/iron supplements from food
If you need to take calcium or iron supplements, try splitting up the timing even further from food and levothyroxine. Here is an example schedule:
| Time | Medication/Food |
|---|---|
| 7 am | Levothyroxine |
| 8 am | Breakfast |
| 10 am | Calcium supplement |
| 1 pm | Lunch |
| 4 pm | Iron supplement |
| 7 pm | Dinner |
This allows 3 hours between levothyroxine and the next food/supplement, and then 3-4 more hours before the next supplement. Maximizing these gaps can help levothyroxine absorption.
Switch to taking levothyroxine at night
Some studies have found taking levothyroxine at bedtime leads to better absorption compared to morning dosing. One theory is there is less interference from food, drinks, medications, and supplements at night. Before bed is essentially an extended “empty stomach” state.
However, switching your timing should be discussed with your doctor first, as bedtime dosing isn’t right for everyone. But it may be worth trying if you continue to struggle with absorption issues from morning levothyroxine.
Consider switching levothyroxine brands
There are several brand names and generic formulations of levothyroxine available. The FDA sets pharmaceutical bioequivalence standards to ensure different versions absorb similarly. However, some brands may work better for individual patients.
Talk to your doctor about switching from a brand name like Synthroid to a generic, or trying another generic. Tirosint is a unique liquid gel capsule form of levothyroxine that may offer enhanced absorption. Getting your thyroid levels rechecked after 6 weeks on the new formulation can help determine if it’s a better fit.
Allow 2-4 weeks for absorption changes
It takes time for changes to improve levothyroxine absorption and show up in thyroid blood tests. Be patient and stick with any absorption optimization steps for 2-4 weeks before expecting to see a difference in thyroid levels or symptoms. Taking your dose consistently at the same time each day on an empty stomach also helps ensure stable blood levels.
Get tested for celiac disease
People with undiagnosed celiac disease often have impaired levothyroxine absorption, likely due to damage in the small intestine where absorption occurs. Getting tested for celiac disease is recommended if you have continuing malabsorption issues.
Celiac is an autoimmune disorder triggered by eating gluten. It causes inflammation and injury to the small intestinal lining, resulting in poor absorption of nutrients, levothyroxine, and other medications. Going gluten-free following a celiac diagnosis helps heal the gut and resolve medication absorption problems.
Check for low stomach acid
Stomach acid aids in the breakdown and absorption of levothyroxine tablets. Some studies have found people with low stomach acid (hypochlorhydria) don’t absorb levothyroxine as well as those with normal acid levels. Older adults and people on acid-suppressing drugs are more prone to this issue.
Symptoms of hypochlorhydria include bloating, belching, nausea, abdominal pain, diarrhea, and feeling full easily at meals. Diagnosis involves stomach acid testing. Treatment options include trying betaine HCl supplements or discontinuing medications that reduce acid production.
Consider natural thyroid medication
Natural desiccated thyroid medication (like Armour Thyroid) is made from dried animal thyroid glands. It contains T4 plus T3, the two hormones secreted by the thyroid. Some patients report better absorption from natural thyroid compared to synthetic T4 alone. However, it may not be suitable for all patients.
Talk to your doctor about whether natural thyroid is an option if you continue struggling with levothyroxine absorption. Close monitoring of thyroid levels is important when switching. Most endocrinologists are comfortable prescribing natural thyroid when appropriate for individual patients.
Evaluate for gastric bypass issues
Patients who have had bariatric weight loss surgery like gastric bypass are at high risk of medication malabsorption, including levothyroxine. Anatomical changes to the digestive tract impair absorption in the GI tract.
Gastric bypass patients may need higher than average levothyroxine doses to compensate, frequent thyroid level checks, and special formulations like liquid or softgel capsules. Work closely with your doctor and bariatric team to ensure adequate levothyroxine absorption post-surgery.
Rule out other absorption conditions
Rare disorders like pernicious anemia, atrophic gastritis, Crohn’s disease, and celiac sprue can sometimes impair levothyroxine absorption. Testing helps diagnose these conditions. Treating the underlying disorder often resolves the malabsorption.
In some cases, intravenous or intramuscular levothyroxine may be needed to bypass the gastrointestinal absorption issues. This method ensures full dosing is achieved despite impaired GI absorption capabilities.
Consider adding T3 medication
For individuals who don’t respond optimally to T4-only levothyroxine, adding T3 thyroid medication may help. Liothyronine (Cytomel) is a synthetic T3 hormone that directly boosts T3 levels. Combination T4/T3 therapy can help relieve persistent hypothyroid symptoms in some patients.
However, T3 has a short half-life and is difficult to dose correctly. Too much causes hyperthyroid side effects like heart palpitations, anxiety, and bone loss. Proper dosing requires frequent testing and monitoring by an experienced endocrinologist.
Get retested until optimal
Keep following up and getting your thyroid levels rechecked if you are still experiencing hypothyroid symptoms, even after trying absorption optimization steps. It may take some trial and error to find the perfect dose, brand, and timing of levothyroxine for your body.
The goal is a TSH level in the optimal range, along with relief of symptoms. This indicates you have reached adequate absorption and dosing. Be your own health advocate and keep working with your doctor to ensure the best personal outcome.
Conclusion
Improving the absorption of levothyroxine is possible with a few practical strategies. Take your dose consistently on an empty stomach. Separate any interacting supplements or foods by 3-4 hours. Consider switching brands, bedtime dosing, or natural thyroid options if needed. Allow time for changes to take effect. Get your thyroid levels retested until you achieve success.
Absorption difficulties can often be overcome with the right individualized changes to your levothyroxine regimen. Working closely with your healthcare provider to identify and treat any underlying absorption disorders is also key. Optimizing your levothyroxine absorption and thyroid levels is important for relieving hypothyroid symptoms and staying healthy.
