9 Supplements Which Could be Harming your Thyroid: Are you taking any?

9 Supplements Which could be Hurting your Thyroid

Supplements can either Help or Hurt your Thyroid

If you know me then you know that I'm a huge fan of using thyroid supplements to augment your existing thyroid therapies. 

Thyroid supplements, as long as they are used correctly, can seriously help improve your overall quality of life by improving thyroid function. 

But this assumes one very important thing:

You are using the RIGHT supplements for your thyroid

Because just like they can help your thyroid they can also very easily hurt your thyroid as well

And there is so much misinformation about thyroid treatment and management in general out there that much of this information is either misunderstood or not known. 

Let's draw the curtains here and talk about the supplements that are potentially HARMFUL to your thyroid. 

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Be Careful with These Supplements

Remember:

Your thyroid is a complicated hormone system which is regulated at many levels. 

And the way that supplements can impact your thyroid can occur at any (or many) of these regulated levels

Some supplements directly slow down thyroid function or can damage your thyroid while others can negatively impact your thyroid medication and thus reduce thyroid function. 

The following list of supplements includes nutrients and vitamins that you should be aware of though you may not necessarily need to avoid them 100% (we will get into this in more detail in a minute). 

So please don't scan through this list and assume that all of these nutrients are "off limits" because that isn't true!

Instead, use a nuanced approach to make sure that you are using them correctly. 

#1. Iron

The first on this list is iron. 

Iron is actually an incredibly important nutrient for your thyroid but it's what I call a Goldilocks nutrient. 

You need just the exact right amount in order to feel better and improve your thyroid. 

How does iron impact your thyroid?

In several ways, but the most important is its impact on thyroid function generally (1). 

Low iron leads to low thyroid function which leads to reduced iron absorption and thus iron deficiency. 

So most thyroid patients think they can just take some iron and call it a day. 

Unfortunately, it's not that easy. 

Iron supplements have the ability to react to thyroid medication taken by mouth and they can completely inactivate it. 

So if you take iron without taking it appropriately you can actually reduce thyroid function and cause worsening hypothyroid symptoms

How do you correct this problem?

Iron is one of those nutrients that must be taken 4 hours AWAY from any thyroid medication that you are taking (this includes all types). 

You do not need to avoid iron 100% if you have low thyroid function but you should be aware of its impact on your thyroid medication (if you take any). 

And be sure to look at your multivitamin ingredients and other supplement ingredients because you might find iron lurking in there. 

#2. Calcium

Next up is calcium and calcium does something very similar to iron. 

Calcium is another 'binder' of thyroid medication. 

While it doesn't harm your thyroid directly it can absolutely bind to and inactivate thyroid medication (2) if you take them at the same time. 

Calcium is found in all sorts of multivitamins and supplements and it's often recommended by conventional doctors in women who are suffering from bone loss. 

There's a good chance you may be taking calcium and not realize that it can negatively impact your thyroid medication. 

Like iron, you must take calcium at least 4 hours away from your thyroid medication. 

The only two ingredients which require this strict 4 hour period are calcium and iron, though, so don't let other ingredients stress you out too much. 

#3. Biotin

Biotin gets a bad reputation among thyroid patients who don't quite understand how it impacts the thyroid. 

Most people believe that it has some negative impact on the thyroid but they can't quite define that impact and they don't completely understand it. 

Let me set the record straight:

Biotin does not have any direct negative impact on thyroid function. 

Let me say that again...

Biotin is not dangerous for your thyroid. 

But it DOES have an impact on the accuracy of your thyroid lab tests which is why it's included here. 

Biotin, if taken in high doses, can react with the thyroid testing assay and make it look like you have MORE thyroid hormone in your system than you really do. 

So if you are taking high doses of biotin and then you get your thyroid lab tests drawn and tested, it may look like you are taking a higher dose (3) (even when the opposite is true). 

But remember:

It impacts the lab TEST and not your thyroid FUNCTION. 

The simple solution to the biotin problem is to just avoid taking your biotin dose 2-3 days before you get your labs drawn. 

Problem solved!

Don't avoid biotin because of this but do use it correctly. 

#4. Iodine

I already know what you are thinking on this one:

"How can you say iodine is dangerous when you recommend using it and put it in your own supplements!?". 

I do recommend iodine and I think that most thyroid patients are not getting ENOUGH of it. 

But I also believe that many people misuse iodine by using the incorrect DOSE and by using it without first paying attention to other important nutrient levels. 

And THIS is what causes the issues that people have with iodine. 

Taking high doses of iodine can absolutely be dangerous but you must understand what a "high dose" actually means

Small to medium doses of iodine (such as those found in my supplements) within the 50mcg to 200mcg dose are perfectly fine and safe for 99% of people. 

natural thyroid supplements version 2

You don't get into trouble until you start using doses higher than 12.5mg per day. 

Sometimes these doses even go all the way up to 50mg per day. 

Once you get into these high doses you start to increase your chance of developing autoimmune thyroiditis, Hashimoto's, and even Graves' disease. 

The bottom line?

Use iodine but don't use excessively high doses as they are increasingly dangerous without any increase in benefit compared to lower doses. 

If you stick to any of my supplements here you should be good to go because they are formulated with all of this information in mind. 

#5. Thyroid Glandulars

I've been critical of thyroid glandulars in the past and now I want to walk back my previous statements with a bit of added caution. 

If you aren't aware of thyroid glandulars let me fill you in: 

Thyroid glandulars are portions of animal thyroid glands which have been dried and crushed and added to over the counter supplements. 

This should sound very familiar to you, especially if you take any medication which falls into the natural desiccated thyroid camp. 

Because this is nearly identical to the way that NDT medications such as armour thyroid are created. 

There's one big difference, though: 

Thyroid glandulars are not supposed to contain any active thyroid hormone (such as T4 or T3) whereas NDT is supposed to contain these hormones. 

But the problem with some thyroid glandulars is that they DO contain some amount of thyroid hormones and this is why they can be dangerous. 

You never want to take any supplement which may contain active thyroid hormones as they will be inconsistent in their dose and they WILL interfere with your ability to interpret your thyroid lab tests. 

This is why thyroid glandulars make this particular list. 

But are glandulars dangerous if they do not contain thyroid hormones?

This is where I've changed my mind. 

I used to think they didn't have a place in thyroid treatment and management but I've since changed my mind after I've been using them more recently. 

As long as your thyroid glandulars come from a reliable source AND they do not contain any active thyroid hormones they can be very helpful for thyroid function. 

They are especially helpful in those people who don't have a thyroid gland because of thyroid surgery, in those who are post radioactive iodine ablation, and in this who have end stage Hashimoto's. 

#6. Fiber

When most people think about fiber they probably think about foods high in fiber but there are also supplements which are high in fiber as well. 

These include things like Metamucil, Citrucel, Benefiber and so on. 

All of these are over the counter supplements which contain massive amounts of fiber. 

I'm not going to get into whether or not fiber is healthy for you here but you should know that fiber CAN impact your thyroid. 

It impacts your thyroid because it can SLOW down the absorption of your thyroid medication if you use your fiber supplement around the same time of day as your thyroid medication. 

If you are taking a fiber supplement (of any type) just be sure to take it AWAY from your thyroid medication. 

Because there's really no reason to take your fiber supplement at the same time of day as your thyroid medication you should separate them out and take one in the morning or one in the evening (if you even use a fiber supplement, that is). 

#7. Caffeine

Next on the list is caffeine. 

And let me take the unpopular position here and just say that if you have thyroid disease of any type then you should be avoiding caffeine 100%. 

This includes all sources of caffeine including coffee (which has a negative impact on your thyroid by itself (4)), energy drinks, sodas, and any other source of caffeine. 

Why do you need to avoid it?

For several reasons: 

The first is that caffeine by itself has a stimulatory effect on your intestinal tract. 

The more caffeine you take the faster your intestinal tract will move and the less time your thyroid medication has to be absorbed. 

Caffeine will almost always reduce the absorption of your thyroid medication if it's taken anywhere near your thyroid medication (again, including all types of thyroid medication). 

But there's another reason...

Caffeine also has a stimulatory effect on your adrenal function and virtually every person with low thyroid also suffers from adrenal problems (to some degree). 

So caffeine not only negatively impacts the absorption of your thyroid medication, but it can also negatively impact your adrenals which WILL impact your thyroid function. 

Do your best to stay away from caffeine from all sources but especially caffeine supplements or pre work out supplements which contain caffeine. 

#8. Acid Blockers

I've included acid blockers here even though they are technically an over the counter medication and not a supplement. 

They could be considered a supplement because they are so easy to purchase (they can be bought at most box office stores) and people use them so often they might as well be considered supplements. 

It turns out that while acid blockers are terrible for your general health, they are also terrible for your thyroid. 

Acid blockers work by reducing the amount of acid that your stomach can produce. 

This may reduce the symptoms of acid reflux but it comes at the cost of reducing virtually every other nutrient that you need to absorb in your intestinal tract. 

It also reduces the absorption of medications, supplements, leads to nutrient deficiencies, and disrupts your gut microbiome. 

If you have thyroid disease you do NOT want to take acid blockers for conditions such as acid reflux. 

It will worsen your thyroid function directly and lead to nutrient deficiencies that will further harm your thyroid (such as iron, B12, and magnesium deficiencies). 

#9. Estrogen enhancing supplements

Estrogen is obviously a good thing and something that you want to have an adequate amount of in your body. 

But you can get into trouble if you take supplements or medications which either enhance estrogen levels or directly provide your body with estrogen. 

Estrogen has a stimulatory effect on something known as thyroid binding globulin (5). 

Thyroid binding globulin is the protein which holds and carries thyroid hormone in your bloodstream. 

If you have high levels of thyroid binding globulin then there is a limited amount of thyroid which can interact with your cells thus changing the state of thyroid hormone. 

Estrogen supplements are not bad or harmful but you should be aware of the impact that they have on thyroid hormone metabolism. 

If you take these supplements you need to account for them when you adjust or interpret your thyroid lab tests. 

If you don't then you may not make the appropriate adjustments to your thyroid medication. 

Final Thoughts

Taking supplements if you have thyroid disease (of any type but especially hypothyroidism or low thyroid function) can be incredibly helpful!

Just realize that not all supplements are "good" and that those who have thyroid problems are in a unique circumstance compared to other people. 

You also can't, and shouldn't, count of your doctor to know these things!

Most doctors are barely aware of the biotin issue I mentioned above (even though it can seriously impact the accuracy of your lab tests) and only a handful are aware of just how strong of an impact things like calcium and iron have on your thyroid medication. 

This means it's up to YOU to be aware of these things!

Now I want to hear from you:

Were you aware of these supplements and how they impact your thyroid?

Are you taking any of these supplements or nutrients already?

Are you planning to change how you take them?

Or do you have any other suggestions to add based on your own experience?

Leave your questions or comments below! 

References (Click to Expand)

9 supplements which are hurting your thyroid

Dr. Westin Childs

About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 45,000+ people have used them over the last 4.5 years. You can read more about my own personal health journey and why I am so passionate about what I do here.

49 thoughts on “9 Supplements Which could be Hurting your Thyroid”

  1. Thank u for sharing, I’ve bn taking a supplement from Dr Dan Colbert(divine health) called thyroid zone along w/nature thyroid 48.5mg. Usually take supplement 2 hrs after thyroid meds. Now my functional MD has increased thyroid med to 65mg becuz my TSH score was 3.6. My T3 & T4 r normal. Im menopausal for 3 years and on topical progesterone and estrogen/with testosterone (low dose) My question is I’m still loosing hair..Never had this prob before in my life. It all started when I started taking thyroid meds and hormones. Dr Paul Rothwell does saliva testing w/blood work. Anyhow one of my friends mentioned I should get in liquid iodine and lower my thyroid meds gradually. She did this and her hair quit falling out. I’m confused. Could u send me some advice.. ThAnk you and may gods blessings keep providing u with wisdom..

    Lisa Keith

    Reply
      • Hi Dr Childs,
        I am typically fairly hypothyroid
        I had until more recently taken 180 mg ERFA ( i believe dessicated)
        I have labs that are low T3, T4 and very low TSH. Having the last 2 months waking up in the wee hours with rapid heartbeat, some weight gain and fatigue. I went off all ERFA suspecting the type of thyroid replacement.I have been supplementing with TRH ( peptide) and have been trying to supplement back in some ERFA, but back to rapid heartbeat and no sleep even with very lowered doses. 30 mg and then I bumped up to 60mg.
        I feel like the supplementing TRH is the right thing to do but maybe I need to switch to another thyroid med? Would love to hear your thoughts.
        Lisa

        Reply
  2. I have thyroid nodules for 10 yrs
    I have ozone treatments.
    Dr told me my nodules are solidified and not to worry about it
    But lately my blood pressure is very irregular
    High pulse to very low pulse 40 pulse to 90
    High bp to normal bp
    I can’t get results

    Reply
  3. thank you for all this great information about thyroid dysfunction. I have Hashimoto’s and will be buying some of your supplements to take.

    Reply
  4. Thanks so much for providing excellent products and research based resources. My supplement question concerns the use of vitamin c. I have read that supplementing with vitamin c May positively impact the absorption of levothyroxine. Do you have any suggestions as to resource material that supports this ?
    Many thanks…..

    Reply
    • Hi Marjorie,

      I’ve never seen any studies which show that vitamin c helps with thyroid medication absorption. It doesn’t mean they don’t exist, though!

      Reply
  5. I have had hypothyroidism for 35 years and been on Synthroid, Levothyroxine and natural during this time. Nine months ago I broke our in a red rash. Biopsy came back as Lichenoid dermatitus. It itches and moves around. Currently hands, elbows, knees. I’ve changed thyroid meds to Levoxyl because it is believed the fillers in my other brand of levothyroxine is the cause.
    My daughter read an article stating it is caused by T4 overdose.
    Have you any info on this?

    Reply
  6. This is a very helpful and interesting article. My question is regarding taking acid blockers. I have been taking medicine for acid reflux for many years. I cannot go without it because it flares up if I do. Do you have any recommendations on what I can take for acid reflux that will not affect my thyroid function? Thanks!!

    Reply
    • Both my cousin and I have found our acid reflux triggers to be diet related. She had to cut corn products and I had to cut dairy and limit my tomato intake. Other triggers for mine I’ve figured out are too much sugar/sweets, soda (haven’t had in years) and going too long between meals. Both of us have come off of our acid reflux meds after making diet changes. Worth digging into!

      Reply
  7. I stopped Biotin because I thought it was interfering with Thyroid T3 (only) medication now I will be restarting (Thank You)
    I started taking Melatonin brilliant for sleep very relaxing consequently put on 7kg so this must have a negative effect
    on Thyroid meds
    Thank You so much for all your great advice

    Reply
    • Did you changed your thyroid medication brand? I am asking because I had big problems when from the pharmacy they replaced my usual brand of Levothyroxine with another one. I was feeling worse and worse by day, and gaining lots of weight even though the lab tests were ok. Only after 6 months the lab tests changed and we realised that my body wasn’t absorbing that brand of thyroid medication at all. Now, after about 8 months after I came bach to my old brand I started to see results and feel much better.

      Reply
  8. Dr. Childs,,, I have to take acid reflux medication twice a day. It is Famotidine, 20 mg. I also take Spironolactone because I cannot take blood pressure medicine. My tsh level dropped to 0.13 and I felt horrible. No energy, shaky, anxiety, headaches, freezing cold and extreme exhaustion, have a hard time sleeping. Balance is unsteady. I take Levothroxine 100MCG every morning around 6 am. An hour later I take my acid reflux medicine and then an hour later eat breakfast and take the water pill, NO caffine. My level is suppose to be between 1-1.5 which I feel good then. Why would it be dropping so mucch. My doctor did lessen my meds but am wondering if they are still to high. Thank you for any advice you can give me. Shirley

    Reply
  9. You say that thyroid glandular can be helpful. I have no thyroid and I take armor.

    How might the addition of thyroid glandular be helpful to me?

    thank you.
    Ellen

    Reply
    • Hi Ellen,

      Thyroid glandulars contain additional proteins, enzymes, and precursor hormones that the human thyroid gland would need/use were they available. If you do not have a thyroid, your body can still utilize these ingredients to improve thyroid function throughout the body.

      Reply
  10. Dr Childs, I would like more detailed information on taking estrogen and thyroid medication. How do we get the most benefit from each drug?

    Reply
  11. Dr. Dr. Childs, I am a MD and a thyroid doctor, well I was, and I want to congratulate you on being so young and yet able to get it and to understand so much. it took me years to get to where you are. GREAT, so few doctors are able to comprehend what is really going wrong with the human body.

    Reply
    • Hi Dr. Love,

      I appreciate the kind words! It’s rare to find another physician who thinks this way so thanks for stopping by and leaving a comment.

      Reply
  12. Very helpful; thank you. Interesting to read about overdoing iodine; I’ll pay more attention to that (but I always take selenium, as well).

    Reply
  13. Hi Dr Childs, I take Armour Thyroid and usually about 4 hours later, with a meal, I take a grass-fed beef liver supplement. Is that ok to do? BTW I thoroughly enjoy watching your videos as I have learned so much from you. Thank you again.

    Reply
  14. I have to take Acifex because of Sjogren’s. My esophagus is extremely impacted if I don’t. I think It’s a real catch-22 when it comes to saying not to take them. My last esophageal dilation was problematic because I had stopped taking an acid reducer. It was bad.

    Reply
  15. I recently found out that I have Hashimotos autoimmune but my thyroid tests are ok. Years ago I was treated for hyperthyroidism until my thyroid “started to work by itself”. I see an endocrinologist next month….but, I also just learned I have Barretts Esophagus…… Do I have to pick which one to treat? (69 yrs, f, overweight, trying to decide between cervical &/or lumbar disk replacement). Thanks….

    Reply
    • Deni,
      Have you gone to a good chiropractor or osteopath? Sometimes if my back is out it pinches the nerve to the stomach or other digestive organs. Since you said you have back issues, maybe do a consultation to find out what disk issues are affecting what body organs.

      Reply
  16. I am currently on 88 mcg of levothyroxine. I was taking Biotin for
    hair, skin and nails. My endocrinologist told me to stop taking
    it because it was affecting my thyroid. If I understand your
    statement, it just affects the lab tests. I will contact him because
    my hair is thinning. It might be genetic, however.
    A friend who also has hypothyroidism recommended folic acid.
    She goes to the same doctor as I do. Your thoughts on folic
    acid please?

    Reply
  17. I am learning so much about thyroid. I had radioactive treatment years ago but the last couple of years I have not felt like myself. I am on caffine big time trying to keep going. I am 75 now and several of my family have thyroid issues. I am learning so much from you. Thank you.
    Frances

    Reply
  18. Hi, Dr. Childs. I’m currently taking 12.5 mg iodine three times a week which seems to be safe according to your information. I do eat some dark chocolate each day but due to caffeine, I’m assuming I should stop this. My new doctor recently switched my med to Thyroid NP from Levothyroxine, which I had been on for years and didn’t seem to help. In spite of all of these changes and improvements, I still experience ‘thyroid fullness’ at times and can’t seem to relate it to anything particular. Any suggestions? I’m also having trouble getting your list of foods for thyroid. I try downloading but nothing happens. Any other way of getting it? Thanks so much for all of your information, your videos and help with thyroid issues.

    Reply
  19. I take prescribed med, FAMOTIDINE, 20MG., now once a day. was taking it morning and night. The doctor has cut the morning dose so just doing night before bed. Will this still affect my thyroid medication, Levothyroxin 88MCG?

    Reply
  20. Hello Dr. Childs, I have had a total hysterectomy and no longer have either of my ovaries. I wear a hormone replacement patch Vivelle Dot which contains estrogen only. Would this affect my thyroid and/or labs? Thank you so much for your assistance and all of the educational material that you provide.

    Reply
    • I’d love to know this as well. I use to take the vivelle.dot for years but for some reason it stopped working on me so had to switch to pill form but still bioidentical per my Dr. Hoping that doesn’t interfere.

      Reply
  21. Dr. Childs,
    I am a practicing Pharmacist of 45 years. I have been dealing with hypothyroid long before we had a name for my condition, Hashimoto’s Thyroiditis. I have also spent many hours in research trying to understand and convince doctors what I needed in order to function. Your research and knowledge is amazing. I send all my Thyroid patients to your site to learn all they can about their disease. Thank you for giving me peace of mind. I know my patients have a place to go and learn about and how to move forward in the their treatment therapy.

    Reply
  22. My doctor confused me. My TSH was 0.0266. Every other thyroid test was normal as were all of my test results. The same result in 2019. This time she took me off my levothyroxine completely for 3 months, ordering new labs in December. I have been taking 75 mcg. I realize this result was in the hyperthyroidism range but she didn’t even mention it on the previous test. I guess I wonder if this was an extreme action. I already feel the belly bloat and tiredness after one month. Your opinion?

    Reply
  23. I’m 70. Taking armour Forest MGF since age 12 where I weight 154 after age 11 had D&C operation. I weighted 140 9years ago. I’m 174 # now. Drink alot of Coffee the last 2 years. Green tea before that. Labs normal. Something is extremely wrong. 9yrs. Horrible looking fat belly last 3 yrs. I need help !!! Please help me

    Reply
  24. I am 67 and have hypothyroidism since I was a teenager. For the last few years I have had bio-identical estrogen and testosterone pellets inserted in my hip twice a year to replace what my body no longer produces. I think they have helped me feel better. Should I stop that?

    Reply
  25. Thank you Dr Childs for the information you offer! it is the best!
    I am 72 years old and I have taken my thyroid meds at night for several years now. It does not interrupt my sleep. Is that ok?

    Reply
  26. Thank you for this article,i found it most informative.
    I have been using estrogen patches now for over 7 mths for my hot sweats and Insomnia,which have helped.
    However,for the last week or so,i have been suffering from heavy limbs,that feel like i have done excessive weight workouts.
    The last time my legs felt like this was when i was taking acid blockers too near my thyroid meds,and after reading this article,i have come to the conclusion,it could be my HRT causing it.
    I have Hashimotos,and over the last few months,my thyroid levels have gone up from 1.35 to 3.

    Reply
  27. I have had my thyroid removed and in the surgery they also took one (or more) parathyroid glands. My PTH blood test shows on the low end. My blood calcium has been low also, so doctor said to take calcium supplements. I take calcium citrate. I will now make sure to take it 4 hours away from the thyroid med (nature-throid now). Is this the best way to deal with my calcium balance?

    Reply
  28. I have hypothyroidism and a Schatzky (sp) ring for which I take Rabeprazole once a day. If I shouldn’t be taking an acid reducer, what is the alternative?

    Reply

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