Some supplements the people take might be harmful for thyroid and in this post we go through some of them.

Are these Supplements Hurting your Thyroid?

Inside: 6 Supplements which hurt thyroid in various ways. Including diagnosis of thyroid disorder, functioning of thyroid, and interfering thyroid medicines.

Hypothyroidism is such a common condition especially affecting middle-aged females. When looking for answers of why females are developing more and more thyroid problems it has been seen the environmental factors can play an important role in this.

Various environmental factors that can affect thyroid include diet, iodine consumption, stress, medications and supplements

There are several supplements for various health conditions in the market and more people are trying to support their overall health through supplements.

It is good to use supplements to support your health, but I always caution my patients that not all supplements are good for all conditions, plus the supplements might not be high quality and might be contaminated with substances which can actually harm your body.

So it’s always best to discuss the supplements with a healthcare provider who is well versed with your medical history and can recommend the right supplements for you. 

Because the thyroid imbalance is such a common condition lot of my patients want to support their thyroid health with supplements but sometimes they are actually doing more harm than benefit to their thyroid.

Some supplements can interfere with your thyroid hormones, some can interfere with lab test results of your thyroid, and some can even cause further damage to your thyroid.

Here I wanted to review some supplements and dietary things that person with a thyroid disorder should stay away from. 

Supplements that Can Hurt Thyroid


Thyroid disorder often accompanies hair loss and nail problems. And the most common supplement which is suggested is biotin to help with supporting hair and nail health.

But high doses of biotin which a lot of patients take can actually interfere with thyroid test results.

Patients who were taking biotin more than 10mg/day were shown to have high T4 and T3 levels. Now with this blood work results, it seems that thyroid is hyperfunctioning and is high, which might lead to either a decrease in the dose of thyroid medicine or your doctor ordering further tests to evaluate if you have a thyroid disorder called Grave’s disease.

So first of all if you are on thyroid medicine you should avoid high doses of Biotin which is anything more than 10mg/ day.

The second thing to remember if you are taking biotin and getting your thyroid level checked,  they might reflect that your thyroid levels are in good range while in reality, they might be low and the results were falsely in the normal range because of biotin.


Yes, you are reading it right that excess iodine can actually harm your thyroid, which was traditionally thought to be healthy for thyroid.

Typically we all know that low iodine has been associated with thyroid dysfunction and several people started taking high doses of iodine, and what we noticed that high doses of iodine also caused damage to the thyroid gland.

So being careful with all sources of iodine is important and the total consumption of iodine whether through iodized salt, diet, supplements should be calculated to support your thyroid.

Most of the thyroid supplements, multivitamins have iodine in them — so you should pay close attention to the levels in them.

American thyroid association do not recommend higher than 500 ugs of iodine supplementation in normal people. 


Moringa is another common supplement used for various health benefits including anaemia, arthritis, asthma, digestive problems, diabetes, high blood pressure. But, in case of thyroid we have to be cautious, the reason being it can reduce the levels of thyroid hormones in the body.

What the research has shown is that — moringa interferes with the conversion of T4 hormone to T3 hormone. 

Free T3 hormone is the active version of the thyroid hormone that our body can utilise. So with lowering the levels of T3 hormone in your body, Moringa can actually harm your health. 

Over the counter (OTC) thyroid supplements

There are several thyroid supplements on the counter and it is frightening to say that some of them actually contain thyroid hormones.

So taking them can actually harm your health. Some of them do not list all the ingredients in it like this study showed that iodine was labelled in only 51% of prenatal multivitamins, rest of the multivitamins contained iodine but was not listed. And this “unlisted” iodine could have interfered with your thyroid hormones.

So unless coming from a good reputable company avoid supplements which claim to support the thyroid. 

Iron and Calcium supplements

If thyroid medicines are taken along with iron and calcium supplements they can interfere with the absorption of the thyroid medicine. Iron is very useful for thyroid functioning and several females are actually low in iron so their doctor would have prescribed them iron supplement. But if you take thyroid medicines with iron or calcium supplements they will interfere with its absorption.

So the trick is to take your thyroid medicines in the morning empty stomach and keep the iron supplementation for either evening or night time.

Acetyl L Carnitine

Acetyl L carnitine is a supplement used to improve fatigue and energy levels as it supports your mitochondria, the energy power house of your body. Acetly L carnitine specially helps with fatty acid oxidation, which is a critical step in producing energy in our body.

Most of the thyroid patients feel fatigued so they might be taking a supplement to boost their energy and that supplement might have Acetyl- L- carnitine as an ingredient.

L-carnitine inhibits both triiodothyronine (T3) and thyroxine (T4) entry into the cell nuclei. This is relevant because thyroid hormone action is mainly mediated by specific nuclear receptors. So L-Carnitine can inhibit the levels of circulating thyroid hormones. There is actually research studies which support the use of Acetly-L Carnitine in hyperthyroid (elevated thyroid) patients.

So it will be a good idea to be cautious with this supplement also and again read all the ingredients of the supplements you take.

Thyroid condition is very prevalent these days and there are numerous supplements in the market who claim to support your health. You should be careful in doing your own research before taking any such supplement, especially as they can have hidden medicines in them and might not be labelling all the ingredients. Also, some of the supplements like iodine have traditionally thought to be useful for thyroid but high doses of those can actually be harmful. 

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The Association Between Gluten and the Development Thyroid.

Research-Based Hashimoto’s Diet and Thyroid Diet

Why EBV Evaluation Should Be Part Of Your Graves And Hashimoto’s Treatment Plan.

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Supplements for thyroid


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Are these Supplements Hurting your Thyroid?