Dropped Your Combo Back to the Lab Again

Thyroid hormones are "Goldilocks" hormones: the dose has to exist "merely correct" for us to feel optimal. Doses that are also high or too low can result in symptoms.

I go tons of messages from people who study that they had begun to feel hypothyroid symptoms later on having their thyroid medications reduced, based on a faulty lab interpretation.

One lady began to lose her hair in clumps; another became nearly bedridden!

Upon reviewing their labs and history, I realized that both had something in common: they had been feeling great on a regimen of T4 and T3 medications, but were found to take low TSH levels, which suggests hyperthyroidism or thyroid medication overdosing.

This finding prompted their dr. to reduce their medications.

To foreclose this from happening, I recommend doing a full thyroid console to get the full movie of what'south going on with an private'due south thyroid role. In club to become authentic lab tests, however, there are several factors that should be taken into consideration.

This article presents an in-depth discussion on:

• Recommended thyroid lab tests (and WHEN to test for authentic results)
• How to get accurate results with T4, T3, and T4/T3 combination medications
• Supplements and medications that may affect lab results
• What to practise if yous go a questionable lab result

Recommended Lab Tests

When get-go initiating handling with thyroid medications for hypothyroidism, guidelines recommend testing thyroid function about iv to half-dozen weeks later on the start of the treatment, to determine if the dose of medication is correct. It may exist prudent to run these tests sooner and more oftentimes if a patient is experiencing symptoms of hypothyroidism, hyperthyroidism, or both.

In add-on to looking out for symptoms of hypo- or hyperthyroidism, I also recommend monitoring thyroid levels regularly to ensure the medication dose is still appropriate.

I recommend the following thyroid tests to measure your response to medications:

• TSH (Thyroid Stimulating Hormone) – TSH is a pituitary hormone that responds to low or high amounts of circulating thyroid hormone. People with Hashimoto's and central hypothyroidism (a rare type of hypothyroidism) may have a normal reading on this test. In advanced cases of Hashimoto's and primary hypothyroidism, this lab test will be elevated, as the torso will indicate the product of more TSH to cope with the lack of thyroid hormone. (Read this mail service about interpreting the TSH exam for more data.) In Graves' illness and hyperthyroidism, TSH levels volition be low.
  • Optimal reference range: between 0.5-two μIU/mL
• Gratis T3 and Free T4 – Triiodothyronine (T3) is our master biologically agile thyroid hormone. About 20 pct of our T3 hormone comes from thyroid secretion straight, while the remaining 80 percent is produced when the thyroid hormone thyroxine (T4) is naturally converted to T3 inside our bodies. While T4 is 300 percent less biologically agile than T3, it is critical to our body's ability to produce adequate and healthy levels of the needed T3. T3 is sometimes called our "become" hormone because it tells our body to boost metabolism, grow hair, and create more energy. Complimentary T3 and T4 tests measure out the levels of agile thyroid hormone circulating in the body. When T3 and T4 levels are depression, but TSH tests are in the normal range, this may pb your doc to suspect central hypothyroidism.
  • Optimal T4 reference range: 15-23 pmol/50
  • Optimal T3 reference range: 5-vii pmol/50

If your doctor does not order these tests for you, you can pay out of pocket and order them yourself through a visitor like Ulta Labs.

If your thyroid labs appear to be inside the "normal" conventional ranges, but are non in the optimal reference ranges as noted above, yous may however feel thyroid symptoms. (You can acquire more about each of these tests and optimal ranges in my article on the peak tests for diagnosing and monitoring Hashimoto's.)

Please note, however, that depending on the blazon of thyroid medication you are taking, you may need to fourth dimension your lab draw and intake of thyroid medication, in order to ensure yous get the well-nigh accurate lab results. (More than on that in a minute!)

Optimizing Thyroid Medication Absorption

Before we talk about timing your lab depict, let'southward review how to take thyroid medications for proper absorption.

I recommend that you take your medication consistently at the same time each day, with a glass of water, at least thirty minutes before nutrient. (Most doctors and pharmacists recommend taking them in the morning, upon waking.) Avert taking acid reflux medications, magnesium, calcium, and iron supplements within 4 hours of taking thyroid medication, as they can impair thyroid medication assimilation.

Absorption may as well be impaired past foods such as soybean, cottonseed, walnuts, and fiber.

Beverages (non including h2o) can impair absorption as well. Of note, coffee can reduce the absorption of T4 in the intestines. (The T4 medication Tirosint may exist an exception to this — delight see my Tirosint commodity for more information.)

Still, hot lemon water is an exception. Taking your thyroid medication with hot lemon water can offering the acerbity needed to aid absorption (and is too keen for helping the liver to detox).

Timing Thyroid Medications for Optimal Lab Results

Optimally arresting your thyroid medication will help to ensure the torso is getting adequate thyroid hormone, and may improve results when you practice exam your labs. However, fifty-fifty if yous are getting adequate thyroid hormone and the body is arresting it, there are factors that may lead to abnormal lab results, and steps you can take that will ensure accuracy.

The kickoff stride to consider is when to have thyroid medications, if yous are planning on heading to the lab. The timing of your thyroid medication may touch on the accuracy of your thyroid examination results, depending on what blazon of thyroid medication it is.

The recommendations for timing thyroid meds differ depending on the type of medication you have. Permit'southward dive into the recommendations for each type of medication.

Recommendations for Those on T4-Only Medications

T4-only medication (such every bit Synthroid, Levoxyl, Tirosint, Eltroxin, and generic levothyroxine) has a five- to 9-day half-life, which ways that once you have go stable on the electric current dosage, it can have up to nine days for 50 percent of the dose to clear the body. T4 has a slow and steady release and won't produce many fluctuations that can make a person experience similar they're on a thyroid roller coaster.

Whether you take your T4 medication right before your lab tests or haven't taken it for up to 48 hours, your TSH value should exist the same. Thus, you volition become an accurate representation of your TSH value whether or non you take your T4 medication earlier a lab test.

The same goes for free T3 levels when you have a T4 medication. The costless T3 level volition also be relatively constant.

Levels of free T4, however, will peak two hours after your T4 medication is taken.

And then allow's say y'all take your T4 medication at 8 am and accept your claret test at x am – your thyroid labs may evidence that your T4 is falsely elevated. This may result in your doctor lowering your medication, when in reality, your T4 levels may be within range for the rest of the day, with the exception of that two-60 minutes, mail service-dose peak.

In most cases, taking a T4 medication the morn before your lab examination will not be an issue, as most doctors arrange the dosages according to the TSH, which stays stable after T4 dosing.

Yet, to go a reading of your T4 levels that is reflective of nigh of the solar day, you would want to postpone your T4 medication until afterwards the lab test.

Thus, when taking T4-merely medications, I more often than not recommend delaying your thyroid medications until after your lab examination. For best results, schedule your thyroid labs early in the forenoon, and bring your thyroid medications to the engagement to take them right later the lab draw.

Recommendations for Those on T3-Containing Medications

If you're taking a T3-containing medication (such as Cytomel or liothyronine) to optimize your free T3 levels, the timing of your tests matters.

Correct afterwards a dose of T3-containing medications, free T3 levels tend to rise, and then top at around the iv-hour marking.

T3 has a typical half-life of 18 hours to iii days. That means it could take less than a day for T3 levels to start rapidly failing in your body!

And then, if yous were to take a T3-containing thyroid medication a few hours before your thyroid lab tests, your lab results might show that you have besides much T3, even when you may be accurately dosed. Or, they may be in the normal range, when you are really under-dosed.

T3-containing medications tin can too temporarily modify TSH levels. Researchers who monitored the levels of TSH, gratuitous T3, and free T4 in people with hypothyroidism who were taking combination (T3/T4-containing) medications over a 24-hour period, found that TSH levels may be falsely suppressed.

This is because, right after taking a T3-containing medication, TSH levels drop and stay suppressed for around five hours. TSH levels will so increase until effectually 13 hours post-dosage, where levels will stabilize.

And so in social club to get an accurate reading of your TSH levels on a T3-containing medication, you would need to wait at least thirteen hours subsequently taking your T3-containing medications before testing!

Again, for this reason, I generally recommend delaying your thyroid medications until afterward your lab test. For best results, test thyroid labs early in the forenoon, and bring your thyroid medications to the appointment to take them right after the lab draw.

Recommendations for Those on T4/T3 Combination Medications

If y'all're taking a combination medication that contains both T4 and T3 (such as Armour Nature-Throid, WP Thyroid, or compounded T4/T3), the timing of your tests does matter and may make a huge departure in getting you on an advisable medication dose.

As mentioned higher up, taking any medication with T3 volition kickoff drop TSH levels for around v hours earlier they first rising again. Thus, it is unremarkably all-time to postpone taking your T4/T3 combination medication until after you get your lab tests washed.

So again, with this medication type, I recommend getting your thyroid function tests done first matter in the morning before taking your medications, bringing your medications with yous, and taking them right after you lot consummate your thyroid tests, to ensure that you get the near accurate lab results.

*Delight note: The half-life of T4/T3 combination medications may vary per conception (this can vary depending on the conception and whether it is an immediate or sustained release version), so some people may have a falsely suppressed TSH, even at the euthyroid state (or the state of normal thyroid role), when taking T3-containing medications.

This is when free T3 and T4 testing will come in handy, equally thyroid health can be assessed through optimal levels of free T3 and free T4. Thyroid wellness tin also be adamant by assessing one's list of symptoms.

Supplements and Medications That May Interfere with Thyroid Lab Results

It's important to note that at that place are some supplements and medications that can interfere with lab results, that you should be aware of before getting thyroid lab work washed:

• Biotin — The American Thyroid Association recommends that patients stop taking biotin for at to the lowest degree two days before a TSH examination. Biotin tin result in falsely loftier levels of T4 and T3, and falsely low levels of TSH on lab results. Biotin supplements (taken at v-x mg/day) tin can interfere with thyroid labs and cause a false appearance of hyperthyroidism. There are case reports of people taking biotin and having low TSH, high T4, high T3, and elevated TSH-receptor antibodies (in the absence of hyperthyroid or Graves' symptoms) bear witness upwardly on lab results. That said, lab values practice normalize after seven days of being off biotin. If you're going in for a thyroid lab draw, skip the biotin for two days beforehand, to ensure that it doesn't interfere with the results.
• Supplements containing estrogenic compounds — Supplements that contain estrogenic compounds such as soy, tin can lead to falsely elevated TSH levels. Nevertheless, delight note that I do not recommend products containing soy to those with Hashimoto's, as it is i of the virtually mutual food sensitivities seen in those with the status.
• Medications that interfere with thyroid test results — In addition to supplements, there are sure medications that tin interfere with thyroid lab test results and may lead to faux readings. This type of interaction is known every bit a drug-lab interaction, and two mutual types of medications that interfere with thyroid labs include:
  • Glucocorticoids, dopamine, dobutamine, and octreotide – These tin lower TSH without indicating truthful thyroid dysfunction.
  • Sure NSAIDs (nonsteroidal anti-inflammatory drugs) of the salicylate subclass (specifically, salsalate, diclofenac sodium, and naproxen) – These accept been found to decrease serum T3 and T4 measurements).
• Drug-drug interactions — False alterations of thyroid labs are not to exist mistaken with drug-drug interactions, which occur betwixt thyroid hormones and certain medications, and atomic number 82 to actual changes in thyroid hormone levels. Simply stated, in that location are medications that interfere with thyroid lab results by actually interfering with thyroid hormone function — this means they cause real alterations in thyroid hormone levels. Some of these alterations are clinically significant and may require a dose adjustment of your thyroid medications when taking the ii medications concurrently. I'1000 working on a separate article that goes in depth about these medications, so stay tuned!

What to Do if You Get a Questionable Lab Result

If you feel that y'all may take received an inaccurate lab effect (perhaps y'all've realized the timing of your thyroid medication may have interfered with its accurateness), there are steps you lot tin can take to receive a more than accurate event.

Beginning, try to determine if the timing of your medication in relation to your thyroid lab tests could exist a factor. Writing downward the details about timing and dosages of medications may help pinpoint if and/or how your thyroid medication may take affected your lab result(s). It may likewise be helpful to make up one's mind if you consumed boosted medications and/or supplements mentioned previously, around the time of your thyroid testing.

If you find that the timing of your medications and/or other factors mentioned in this commodity did indeed pb to inaccurate lab results, it may be necessary to retest.

Retesting may involve some planning around when you take your thyroid medications, and possibly delaying other medications and/or supplements by a few hours, so that at that place is no interference when you practice draw your labs.

If after receiving authentic results, yous still feel hypothyroid, are still experiencing debilitating symptoms, or if your lab results do not fall within the optimal ranges (every bit discussed earlier in this article), be sure to re-read the "Optimizing Thyroid Medication Absorption" section of this article (to a higher place) to ensure you are taking your thyroid meds away from foods that can inhibit their assimilation. If y'all are, then it may be time to have a chat with your dr. nigh adjusting your medications.

This may involve:

• Adjusting dosages
• Switching to a different type of medication — for example, many individuals feel better with adding T3 onboard to their current regimen

Please note, however, that there have been recalls in the past, and then make sure to discuss this with your doctor, and cheque out this article on thyroid medications to review all available options on the market. While trying to become on the right dosage of medication, y'all will want to exam your thyroid labs every iv to six weeks to ensure your labs are inside range.

One time you lot get stabilized on your new thyroid medications, you can beginning testing thyroid levels every 3 months to ane year for ongoing monitoring.

I take a gratis, downloadable eBook, Optimizing Thyroid Medications, that provides farther guidance on this optimization process.

Adjacent Steps

As mentioned above, if y'all are post-obit all the steps for accurate lab results but they are all the same coming dorsum abnormal, talk to your dr. most a dosage adjustment.

I recommend that you also investigate the possibility that something else is interfering with the absorption of your thyroid medication, such every bit fillers like gluten, or certain supplements that you are taking.

While some supplements can result in false readings of thyroid levels, others reflect a true alter in thyroid levels — this alter may be an improvement or worsening of levels depending on the supplement. Examples of such supplements include aloe vera, cordyceps, vitamin A, and ashwagandha, which all lower TSH. (I'm working on an article on supplements that tin aid lower TSH naturally — stay tuned!)

In addition to medications that cause faux alterations in thyroid lab results, there are also medications that have actual drug interactions with thyroid hormones, and the contradistinct labs are a existent reflection of how the addition of a new drug impacts the action of thyroid hormones in the body.

In my grooming as a chemist, I learned that at that place are some medications that have a multitude of drug interactions — 1 of these medications is thyroid hormone! Some of these drug interactions may exist clinically meaning, meaning that they can modify the absorption, distribution, metabolism or emptying of the thyroid hormones, necessitating a dosage modify in thyroid hormones while the person is taking both medications.

A person who has been stable on thyroid medications but begins experiencing symptoms of hypo- or hyperthyroidism following the addition of a new medication, should ask about potential drug interactions and request lab tests.

I'll exist sharing more than data about significant drug interactions with thyroid hormones in the future, but for now, I recommend checking with your chemist whenever you outset a new medication to run into if your dose of thyroid medication needs to exist adapted.

In summary, receiving authentic results is of import to ensure no ineffective changes are fabricated to your current medications, and to assess how your thyroid is currently functioning. Once you've identified and addressed things that could be affecting your TSH or T4 lab results, consider retesting with the proper timing of medications and/or supplements for accuracy.

I hope this helps y'all on your healing journey!

P.S. Yous can download a Thyroid Nutrition Guide, 10 thyroid-friendly recipes, and the Nutrient Depletions and Digestion chapter of my first volume for complimentary, past signing up for my weekly newsletter! You will also receive occasional updates about new research, resources, giveaways, and helpful information.

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Note: Originally published in August 2015, this article has been revised and updated for accuracy and thoroughness.

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