If you’re taking a thyroid drug such as Synthroid, you may have wondered, “How long can you go without thyroid medication?” Will it harm you to miss a dose, or will it take it later than normal? Generally speaking, missing a single dose of your thyroid medication will not cause significant harm. But missing several doses over time can cause hypothyroid symptoms, such as fatigue, weight gain, and constipation, to appear.
And yet, some people have been prescribed thyroid medication without any real need for it . Still others may be able to significantly reduce the amount of medication they need by supporting the right health foundations, including gut health. So, “How long can you go without thyroid medication?” is a more individual question than you might think.
In this article, we will discuss
- What can happen when you change your thyroid medication schedule or have other issues with your medication
- When you need thyroid medication
- Why you should keep reevaluating your need for it
- Thyroid medication alternatives
Missing a Single Dose
There’s no reason to panic if you miss a single dose of synthetic thyroid hormone medication (Levothyroxine, Levoxyl). Supplemental T4 hormone (thyroxine) builds up over time and circulates in your bloodstream for a few days, so you likely won’t notice one missed dose .
However, try to be consistent. It’s good to stick to a schedule when taking any medications, and synthetic thyroid hormone works best when taken at the same time every day on an empty stomach.
Unless you miss a dose by 10-12 hours, it’s alright to take your thyroid medication slightly later in the day than you normally would. Any longer than 10-12 hours after your last dose, skip it for that day and take it on your normal schedule the next day.
If you are not producing thyroid hormones due to thyroidectomy (removal of the thyroid gland, usually because of thyroid cancer) or radioactive iodine therapy for Grave’s disease (autoimmune hyperthyroidism), it is even more important to stick to your daily medication schedule. Without supplying those hormones, you may quickly notice hypothyroid symptoms such as fatigue, digestive problems, feeling cold, and more.
Stopping Thyroid Medications
When you have true hypothyroidism, completely discontinuing thyroid medications can quickly lead to symptoms, including:
- Brain fog
- Weight gain
- Dry skin and hair
- Hair loss
- Depression and/or anxiety
Long term, untreated thyroid disease can lead to other chronic diseases such as cardiovascular disease, cognitive impairments, and infertility.
When hypothyroidism is obviously present, there’s no reason to avoid medication. Standard thyroid meds like T4 hormone replacement have few side effects and are considered generally safe when taken as instructed at the correct dosage. However, as we’ll explore below, thyroid medication is increasingly being overprescribed to those who do not necessarily need it.
Are You Absorbing Your Thyroid Medication Well?
Absorption of thyroid hormone medication can be hindered by some foods, other medications, and other chronic health conditions. When you aren’t absorbing your medication properly, it’s effectively the same as taking a lower dose.
A 2017 research review found that the following factors can cause you to absorb less levothyroxine, a common thyroid medication .
- Gastrointestinal illnesses, such as celiac disease, dysbiosis, and H. Pylori infection [4, 5, 6, 7]
- Certain supplements: iron sulfate, calcium citrate, calcium carbonate, and calcium acetate
- Select medications: proton pump inhibitors, colesevelam, ciprofloxacin, cholestyramine, sevelamer, or aluminum hydroxide
Sometimes, liquid T4 medication is a better option for patients who can’t resolve their absorption issues. Research also shows that vitamin C improves absorption of thyroid medication . And when you treat and resolve GI issues, thyroid medication absorption can increase . This may occur even by just changing your diet or other medications.
With increased absorption, you may end up with the opposite problem: You’re absorbing your thyroid medication too well. Symptoms of hyperthyroidism, like anxiety and irritability, feeling hot, and a racing heart rate will tell you to visit your endocrinologist and get your thyroid hormone levels tested.
Thyroid Medication Is Overprescribed
There are some people who would actually feel better without taking thyroid medication, when that medication has been mistakenly prescribed. Unfortunately, misdiagnosis of thyroid conditions is more common than you might think [1, 8].
One study found that as many as 61% of thyroid patients may be unnecessarily taking thyroid medication. In the study, 291 patients were asked to stop their levothyroxine/synthroid medication for 6-8 weeks. Many patients had been on this medication for years without exhibiting thyroid-related symptoms.
After 6-8 weeks had passed, the patients’ thyroid hormones were tested. 60.8% of patients had normal levels of thyroid hormone, meaning they did not require thyroid medication.
When You Need Thyroid Medication and When You Don’t
When evaluating your thyroid health status, often all that’s needed is standard blood tests for TSH (thyroid-stimulating hormone) levels and T4 levels. These tests are very reliable measures of thyroid function . Here are some situations to watch out for when evaluating these test results:
- Abnormally high TSH levels, abnormally low T4 levels: This is classic hyperthyroidism. T4 medication (synthroid) is required. Common hyperthyroid symptoms include abnormal weight loss, racing heart rate, heart palpitations, abnormal blood pressure, menstrual irregularities, muscle weakness, anxiety and depression, and insomnia.
- Normal free T4 levels with slightly elevated TSH: This indicates subclinical hypothyroid or early hypothyroidism. At this stage, medication is not necessary, but you should closely monitor how you feel and watch for underactive thyroid symptoms.
- Normal TSH and low free T4: This means the pituitary gland isn’t working properly. Work with an endocrinologist.
- Low free T3: This results from digestive issues, a too low-carb or low-calorie diet, or systemic inflammation. T3 medication isn’t usually required in this case.
- Normal thyroid hormone levels but elevated thyroid antibodies: This is a sign of Hashimoto’s disease (when the immune system attacks the thyroid gland), but it doesn’t mean that you necessarily need thyroid hormone replacement [10, 11]. Contrary to what many believe, you can have Hashimoto’s disease without developing hypothyroidism.
Alternative Thyroid Medications
In the integrative health world, alternative therapies like T4/T3 combination therapy have become popular alternative solutions to medications like Levothyroxine (Synthroid). However, their ability to resolve thyroid problems increasingly appears to be overstated [16, 17, 18].
A meta-analysis of 11 studies involving more than 1200 patients showed no evidence that T4/T3 therapy was any better than T4 therapy alone .
A 2021 review of 8 studies also showed that the majority of the time, T4/T3 therapy was not associated with any improvements in quality of life compared to T4 alone .
Another 2021 study involving 75 hypothyroid patients compared the use of levothyroxine, desiccated thyroid hormone, and combined T4/T3 therapy. After 22 weeks in one group, participants were moved to another group for 22 weeks. Overall, there were no differences in outcomes between the three groups .
In addition, thyroid autoimmunity (Hashimoto’s thyroiditis) and imbalanced thyroid hormones are two separate issues. Thyroid hormone replacement does not address the root cause of autoimmunity, even if it might temporarily make you feel better.
It might be tempting to search for the best thyroid medication or new supplement, but a simple step-by-step process to address your health foundations should always be implemented first.
- If you truly have hypothyroidism, begin standard thyroid hormone (T4) replacement.
- If your symptoms aren’t resolved by thyroid medication alone, investigate and make changes to improve your gut health.
- Once your gut and microbiome is more balanced, fine-tune your medications and any thyroid supplements.
Keep Reevaluating: How Long Can You Go Without Thyroid Medication?
If you’re on thyroid medication, you should try to stick to a schedule for taking it at the same time every day when possible. But if you take it later than normal or even miss a day, it’s probably not going to send you into a spiral of hypothyroid symptoms.
However, there’s a bigger issue at play. Although thyroid hormone replacement is a very safe and effective therapy, research shows that it’s not always necessary for many patients. In addition, many factors outside of the thyroid can impact thyroid health and function, including gut dysbiosis, leaky gut, and autoimmunity. When these issues are addressed, thyroid function will likely improve as well.
If you would like to be evaluated by an experienced professional to address your thyroid, gut, and overall health, schedule a consultation with one of our practitioners at the Ruscio Institute for Functional Medicine.