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Thyroid School, Issue #13// Supplements that Affect Thyroid Labs


Supporting your thyroid with supplements seems like a good idea, but there are a few cases in which blindly supplementing with well-marketed thyroid-specific products can actually do more harm than good.

No one wants to have labs that are “off”, but when you’ve been dealing with nagging symptoms like fatigue, hair loss, weight gain, and insomnia, seeing that your labs are off and even getting a diagnosis can be sort of a relief, right? It is so aggravating to be feeling so poorly and know in your gut that something isn’t right only to hear the words “your labs are totally normal! You’re the picture of health!”. (Granted, no one WANTS to receive abnormal labs or get a diagnosis, but if you’ve been dealing with debilitating symptoms without knowing why, you get it).

In a day and age when we can Google everything and try to DIY our health through the $35.6 billion dollar supplement industry, it’s important to do so knowing how these seemingly harmless supplements may in fact hinder diagnosis and/or management of your hypothyroidism.

There are a few popular thyroid supplements that many people jump to without realizing the effects they could have on labs:

Biotin: hair loss is a common symptom of hypothyroidism and can really make a person self-conscious. Biotin is a rather safe supplement to take at high doses, BUT it can interfere with your lab results and lead to either misdiagnosis and/or improper adjustments of your medications. Biotin can create a falsely low TSH and falsely high T4/T3. If you’re taking medication and your T4/T3 are high and TSH low, your prescriber may want to decrease your medication. Since the labs are not a true reflection of what is really going on with your thyroid, decreasing your medication may make your hair loss WORSE. Suspect that you have hypothyroidism but your labs always come back “normal”? It could be that high dose biotin making things look peachy-keen when it’s actually not!

Tyrosine: tyrosine is one of the main building blocks of thyroid hormones. Tyrosine is a conditionally essential amino acid (meaning we make most of what we need in the body), but sometimes our body cannot keep up with production and therefore it becomes essential (must get through the diet). Increased demand happens during times of stress and healing. Tyrosine supplementation is popular in thyroid specific supplements as well as mood stabilizing supplements (as it is often touted to help with depression). Taking doses of tyrosine beyond what you need can boost thyroid hormone production a bit too much and lead to low TSH. This can be especially problematic if you’re taking thyroid replacement medication AND supplementing with tyrosine.

Iodine: ah, iodine. This is actually pretty controversial and definitely the Goldilocks of micronutrients. Iodine is essential for thyroid hormone creation, but TOO much is definitely not a good thing. Too much iodine can speed up thyroid hormone production and lead to low TSH and high free hormone levels. Additionally, continually forcing the thyroid to produce more hormone can lead to a build up of a natural byproduct of production— hydrogen peroxide. If there are not enough antioxidants (selenium, glutathione, for example) to quench the inflammation from hydrogen peroxide, it can lead to more thyroid damage. This is especially important for those with Hashimoto’s. A common site of antibody destruction in Hashimoto’s occurs along the pathway where iodide converts to iodine, so if this spot is flooded with too much, it can be highly inflammatory. Additionally, Hashimoto’s is an inflammatory autoimmune condition to begin with, so antioxidants are in greater need.

Main takeaways:

Food sources are almost always safe, but be sure to avoid extremes. Like your momma said: everything in moderation! Be mindful about copious amounts of seaweed and kelp (iodine), try not to drink a ton of kale juice (goitrogens that impair iodine uptake), eat colorful fruits and veggies (antioxidants) close to their whole-food form.

Tell your doctor if you’re taking supplements. I promise, he/she will appreciate knowing. Properly interpreting your labs and dosing your medication depends on knowing the full picture of what’s going on with you. An open doctor-patient relationship is essential for your success in managing your disease.

Don’t blindly supplement. Work with a professional who can run labs and analyze your dietary habits to see if you may be missing the mark somewhere and safely suggest a supplement. I run several panels on clients when we work together.

Here are ways I can help!