Many thyroid patients take their thyroid pills every day as prescribed, yet they don’t feel better. Today I want to look at the factors that impact how your thyroid medication is absorbed, or not.
When I was diagnosed with hypothyroidism in 2003, my doctor never told me that I would be taking my thyroid medication on an empty stomach. It was only in 2009 when I changed doctors (because we moved into a new town) that my doctor told me that I should be taking it first thing in the morning.
Why is this so important?
It is all about getting the maximum absorption of thyroid hormones.
What you are looking for is 100% absorption of your thyroid medication, regardless of which thyroid medication you are taking. Whether it is T4 only, T3 only, or a combination of T4 or T3. If you are not absorbing 100% of your hormones, the result is that you will experience hypothyroid symptoms even if you are taking the pills that are supposed to help you.
The key here is that you don’t want to take it with ANYTHING ELSE.
Anything else means coffee, food, other supplements, or other medications—nothing else. Anything else interferes with the absorption of these thyroid hormones.
Low or no stomach acid
The first step in digestion starts in the stomach. If you have low levels of stomach acid (called hypochlorhydria) or no stomach acid (called achlorhydria), it can impair the absorption of the thyroid hormones.
How do you know if you may have low levels of stomach acid? You may experience symptoms such as bloating, burping, diarrhea, indigestion, hair loss, nails breaking, or gastrointestinal infections.
Do a medical checkup for low stomach acid. Then you can take action: if it is due to an infection, antibiotics may be the way to treat it. Or you may need to take HCI supplements (like berberine, betaine with pepsin, or digestive enzymes) to help increase stomach acid.
Absorption in the small intestine
Let’s have a look at what needs to happen.
The thyroid pills need to be digested and then it must be absorbed in the small intestine. It enters the bloodstream and these beautiful hormones are then delivered to the cells in your body that are used for metabolism, energy, and many other functions.
So let’s have a look at a few important aspects of thyroid medication absorption.
Food and beverage interference
The best thing you can do is not to drink or eat anything for one hour after you have taken your thyroid medication.
The Endocrine Society issued a press release in 2017 titled: “Cow’s milk interferes with absorption of thyroid supplement levothyroxine”. Remember that levothyroxine is the synthetic T4 medication, and what they found was that a glass of cow’s milk significantly decreases the body’s ability to absorb the thyroid medication (2). And it goes for other dairy products and calcium supplements as well.
Unfortunately, many other foods also interfere with the absorption of your thyroid medication, including coffee, soybeans, fiber, grapefruit juice, walnuts, and papaya. (3).
So you may think that you can drink tea, or juice or eat something. But I want to encourage you to stick to the 1-hour “rule”. Don’t eat or drink anything for 1 hour before or after taking your thyroid medication.
Your morning routine
Place your thyroid medication on your bedside table with a glass of water. When you wake up, the first thing you do is take your thyroid medication. Then wait an hour before you have your breakfast.
But what if you don’t have time in the mornings? Say you get up at 06h00, you can set your alarm for 05h00, take your medication, roll back into bed and sleep until 06h00. Or, if you wake up in the early morning hours to go to the bathroom, take it then.
Taking your medication at bedtime
You can also take your thyroid medication at bedtime if it works better for you. A a randomized double-blind crossover trial of 90 patients compared the difference between morning and bedtime intake of lyvothyroxine. The researchers found that taking thyroid medication at bedtime significantly improved thyroid levels. (4).
Another study of 12 women was also published in 2007, comparing TSH and thyroid hormone levels from taking thyroid medication at night or in the morning. The study reported that the thyroid medication taken at bedtime is associated with higher thyroid hormone levels and lower TSH levels. The reason they believe this happens is because of a better uptake of thyroid hormones during the night. (5)
So if you are not a morning person who can wait one hour before having breakfast, you can take it at bedtime. Keep in mind, again, don’t eat or drink anything for an hour before you take your thyroid medication.
Did you know that supplements can also interfere with the absorption of your thyroid medication?
Unfortunately, yes. (3,6)
The general rule for taking any supplements is to take them 4 to 6 hours after taking your thyroid medication.
But if you are taking iodine (in the liquid suspension, not the tablet), you can wait 30 minutes then add it to water and drink it. The problem with capsules is that the gelatin-based capsule can interfere with absorption in the small intestine.
Always think: is this going to interfere with the absorption in my gut? If yes, don’t take it. If not, you can take it. So, anything that you take under your tongue, a patch or an injection, you can take at the same time as your thyroid medication as it does not interfere with the absorption in your gut.
Vitamin C and thyroid medication
Interestingly, you can take water with some lemon with your thyroid medication. A study showed that vitamin C is one of the few substances you can take that can actually help thyroid medication absorption (7).
But before you grab a vitamin C supplement, it would have to be pure vitamin C without the gelatine capsule or any other ingredients. The easiest option is lemon water.
Many prescription and OTC (Over-the-counter) medications can also decrease the absorption of your thyroid medication if you take it at the same time or too close in time.
So, if you are taking any other medication that is listed below, please consult with your doctor or pharmacist about taking your medication at a different time than your thyroid medication (3, 6):
- Androgens (testosterone, DHEA, DHEA-S, DHT, and androstenedione)
- Anabolic steroids
- Antiacids (such asaluminium hydroxide)
• Beta blockers (reduce blood pressure)
- Bile acid sequestrants (such as colestipol)
- Calcium citrate
- Calcium acetate
- Calcium carbonate (Tums)
- Cation exchange resins (such as kayexalate)
- Chromium picolinate
- Ferrous sulphate
- Oral contraceptives
- Phosphate binders
- Proton pump inhibitors
- TKI (tyrosine kinase inhibitors)
- Tricyclic antidepressants
The last part we need to understand that gastric conditions can also interfere with the absorption of the thyroid hormones. These conditions include celiac disease, lactose intolerance, short bowel syndrome, SIBO (small intestine bacterial overgrowth), parasitic diseases, motility impairments, and inflammatory bowel diseases such as ulcerative colitis and Chrohn’s disease.
You may need a higher dosage of thyroid medication than usual because of the lack of absorption, and it may confuse doctors. Some doctors believe that there is a certain maximum dosage strength, but they don’t take into account that the thyroid hormones may not be well-absorbed.
In fact, a study done in 2019 showed that almost all hypothyroid patients with ulcerative colitis needed an increase in their thyroid medication. (8)
You want to make sure that your body absorbs as much of the thyroid hormones as possible. That means that you should take your thyroid hormones on an empty stomach, and wait at least an hour before you eat or drink anything, except water with lemon in.
As always, the key question is: how are you feeling? If you are not feeling better every day, there may be an underlying issue that is interfering with the absorption of the thyroid hormones.
There are several supplements, OTC, and prescription medications that can impact how your body absorbs thyroid hormones.
Also, if you have a gastrointestinal condition, you may also have an issue with absorption and may need a higher-than-normal dosage to compensate for the malabsorption.
Sources and references
- Switch from tablet levothyroxine to oral solution resolved reduced absorption by intestinal parasitosis. Endocrine Diabetes Metab Case Report. 2019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6432983/
- Cow’s milk interferes with absorption of thyroid supplement levothyroxine. The Endocrine Society. Press Release. 2017. Retrieved from: https://www.endocrine.org/news-and-advocacy/news-room/2017/cows-milk-interferes-with-absorption-of-thyroid-supplement-levothyroxine
- Factors Affecting Gastrointestinal Absorption of Levothyroxine: A Review. Clinical Therapeutics. 2017. https://pubmed.ncbi.nlm.nih.gov/28153426/
- Effects of Evening vs Morning Levothyroxine Intake. JAMA Network. 2010 Dec. https://pubmed.ncbi.nlm.nih.gov/21149757/
- Effects of evening vs morning thyroxine ingestion on serum thyroid hormone profiles in hypothyroid patients. https://pubmed.ncbi.nlm.nih.gov/17201800/
- Gastrointestinal Malabsorption of Thyroxine. Virili, C., Endocrine Reviews. 2019 Feb. https://pubmed.ncbi.nlm.nih.gov/30476027/
- Effect of Vitamin C on the Absorption of Levothyroxine in Patients with Hypothyroidism and Gastritis. Jubiz, W., et al. JCEM. 2014 Jun. https://pubmed.ncbi.nlm.nih.gov/24601693/
- Ulcerative Colitis as a Novel Cause of Increased Need for Levothyroxine. Virili, C., et al. Front Endocrine. 2019 Apr. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6476912/