Any link between high T3/ over replacement or u... - Thyroid UK

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Any link between high T3/ over replacement or under replacement and asthma?

Polly91 profile image

Hello helpful people

Has anyone ever noticed they get more wheezy/asthma symptoms when they are over or under replaced with thyroid hormone?

I used to think it was a coincidence but my onset of asthma symptoms seems to coincide with the need for a dose adjustment - usually a reduction.

I’ve never read about this before and my naturopath doesn’t think there’s a link but I’m not so sure. I’d be interested to hear if any of you have noticed this?


21 Replies

Respiratory issues are reported when thyroid abnormal.

I think it’s often indirect, for example - abnormal thyroid causes low ferritin which causes breathlessness.

If you have a existing condition abnormal thyroid will likely exacerbate it.

Do you have any recent results?

Asthma can be a hypo symptom. But, I don't know about over-medication.

Yes, I experience this. It took me a while to work out why. It's not necessarily even having too much thyroid hormone, but it is the effect on your cortisol levels.

Cortisol (especially if low) can exacerbate and trigger asthma symptoms. If you have asthma you almost certainly have adrenal issues and cortisol fluctuations. Dr Berg says asthma is essentially a cortisol problem. Many asthmatics get prescribed hydrocortisone gel or tablets or prednisone for years sometimes. The Asthma forum is interesting, I believe some asthmatics even get referred to endocrinology.

When you raise your thyroid hormone, you put pressure on your adrenals and then when you start doing even normal activity on top, or even without activity, you can suddenly find yourself struggling.

I find it improves with time. On (working potent) Armour it was terrible every time I raised the dose by even a quarter grain. I take my emergency inhaler.

Same would happen with levothyroxine if I suddenly jumped up by a lot.

But being undermedicated is particularly terrible for asthmatics.

Thanks v much all. I don’t have any recent bloods but am due to get them done in next couple of weeks.

My pulse is high 84 and have a slight headache & haven’t slept well for a few days. It’s the wheezing that’s the biggest issue though.

I too had heard hypo can result in asthma getting worse. So I guess that is possible too.

Interesting about low cortisol ? I think I’ve had adrenal fatigue in the past - would that result in low cortisol ? Also had covid 6 weeks ago so that may have put pressure on adrenals ? What actually causes low cortisol?

Thanks for your advice.

DippyDame profile image
DippyDame in reply to Polly91

I have a type of thyroid hormone resistance and need a supraphysiolgical dose of T3 to function

During the time I was trying to find my therapeutic dose of T3-only I hit a miserable spell when I became wheezy and had a "stuffy nose".I was prescribed an inhaler and antihistamine tablets.

Marginal relief.

On high dose T3-only we have to monitor the dose by signs and symptoms

I wasn't aware that those were symptoms of overmedication....until I had read further.

Then it dawned on me....too much T3

I reduced my dose and the symptoms disappeared.

I had no other signs of overmedication

I had previously been diagnosed as asthmatic after a wheezy spell so didn't immediately think " thyroid".

Now I'm not sure about that diagnosis!

I'm still trying to join up the dots related to my (thyroid) medical history....since childhood.

This underlines the importance of very careful monitoring when reliant on T3 -only medication....signs and symptoms are paramount.

Suggest you review your T3 intake for other signs of overmedication, it must be treated with respect...tiny dose changes can make a big difference

Polly91 profile image
Polly91 in reply to DippyDame

Thanks so much DippyDameI was diagnosed with asthma as a child and I was always sick taking antibiotics regularly. My teeth were filled with amalgams. I got glandular fever at 20 and was put on Levothyroxine when I was trying to conceive in my mid 30s- was told I was borderline (TSH was 4.5!)

I only learned about T3 from the brilliant people on this forum when I got v sick with Lyme in 2018 when Levothyroxine wasn’t doing it for me and I’m wondering now if my childhood asthma was related to my thyroid disorder. I call it disorder as I’m convinced I was hyper as a child but by 20s I was hypo. Sounds odd I know.

Dippy Dame have you only experienced asthma with high T3 or have you had with low too?

I’m due blood tests in 2 weeks but don’t know whether to stay on current dose or reduce until my test is done. My wheezing is pretty bad - much worse when I’m lying down (I did wonder if it was dust mites in bed ?) I sound like I’m about 95 and smoked all my life!

I take a combination of metavive I (1 capsule) and III (4 capsules).

Thanks again

DippyDame profile image
DippyDame in reply to Polly91

I was diagnosed as asthmatic about 30 years ago and back then had no idea about my thyroid status. However, the asthma was transient and rarely bothered me again....if it was asthma!Knowing what I know now I'm totally convinced I've always had a thyroid problem, but it was never picked up until I became very unwell.

I was diagnosed with CFS and FM.

Medics had no other suggestions but I found those diagnoses unconvincing so I requested a thyroid test.


Levo helped briefly but eventually I could barely function

It's all in my won't bore you with it here!

Metavive is a glandular supplement not to be confused with NDT which has a known thyroid hormone content

Consequently, the exact T4 and T3 content of the capsules is virtually unknown making precise dosing impossible....or so I understand!

It is possible that you are overmedicated as a result, but labs will verify your levels.

In your shoes I would have a full thyroid test ...

TSH, FT4, FT3, vit D, vit B12, folate, ferritin and thyroid antibodies TPO and TG

The results should then guide your dosing protocol

Post those new results and members will have a look to see what is going on.

Polly91 profile image
Polly91 in reply to DippyDame

Thanks Dippy DameIt makes me cross that medics are happy to give people a “diagnosis” of ME/CF- these are often due to other underlying issues like thyroid (as you say). I’m sorry you had to endure all this. I feel cheated on your behalf.

My Lyme practitioner told me CF/ME is often due to Lyme or other infections even Candida. But my gut tells me the root cause is low thyroid function.

I forgot to mention I had v loose bowels yday too which is another sign of too much T3 (for me at least).

I didn’t take all my metavive last night & this morning and my breathing has calmed down. Slight wheeze but nothing like Friday night & yday.

I will definitely post my results. Thanks again for taking the time to reply.

I have ….a type of air hunger/breathlessness used be a regular symptom when thyroid levels were off, even slightly high or low. I was initially told it was asthma (years ago) and given an inhaler. However, I discovered last year that folate levels were out of balance and when I raised that it sorted the breathing problems! Might be worth checking out

Polly91 profile image
Polly91 in reply to Chumchum

That’s interesting what level was your folate when you felt breathless ? Also was the air hunger breathing issue worse when T3 was high or low?Thanks v much

Chumchum profile image
Chumchum in reply to Polly91

Hi Polly, The folate level varied consistently between 6 and 8. I thought it was okay until somebody on this site mentioned it needing to be in the upper range. I had been taking b12 without a vit b complex supplement for balance. When I took methyl folate and increased level to above 14 the breathing issue initially improved and then completely disappeared. I’m still working on getting the thyroid hormone levels balanced though. Before folate increased, airhunger was there and worsened if thyroid levels were low or high. Worst when low.

Hi polly91

One of my over/under symptoms is that I get out of breath very quickly. I don’t have asthma but I can definitely also relate to that struggling for breath symptom even when doing something not particularly strenuous at all walking up hill I’d have to stop several times

I have been working out my combo doses for sometime now and since raising levo so that I am higher in the range I can say that it is much improved to almost gone mostly. Now I’m just unfit! I would add that so far I haven’t found that t3 helped this. We are all different and probably finding the balance between the two is key here. Just thought I’d add my experience so far. Good luck.

Thank you for this. So did you get asthma type symptoms with too high Levo as well as when thyroid replacement is too low?

How long does it last? Thanks

So with high ft3 and low ft4 amongst other symptoms I have a severe lack of stamina. Really easily out of breath which makes me worn out very quickly. Even with a low ft3 and a higher ft4 I am so much better. Not half as breathless and considerably more stamina. Walking the dogs is a pleasure once more.

As for how long it lasts… it’s difficult to say. We are all different but I’ve been trialling combo treatment for around 18 months. I dropped the t3 off completely around 4 months ago and focused on raising ft4 by increasing levo. I am now at 50% through the range for ft4 but only but only 16 % for ft3 and yet still feel so much more able to do stuff. The breathlessness still comes with exercise but I think this is more a general fitness issue because I haven’t felt able to do anything for 18 months.

Obviously by the time I’ve worked my way round this maze of thyroid issues I will be running marathons lol. I hope this helps you work out what to do next but the hardest thing is understanding that you can’t rush it. I wish you all the patience you need and luck too x.

Thanks so much. I’m already feeling a lot better having dropped my dosage of metavive. I hope you can get your levels to your optimum so you can run those marathons!

Aren’t we lucky to have each other and this forum as doctors just don’t seem to know it all (or much in some cases )

Ah yes. Being treated with Armour and T3 cleared up my long-standing asthma. Briefly reducing my meds last year caused dramatic breathing difficulties within days, that have not completely reversed, still.

Hi Polly91, not sure if it's the same as your experience but I always have temporary chest tightness (that feels very much like my thunderstorm asthma) when im increasing my medication. I've most commonly experienced it with thyroxine, but my sense is that it happens no matter the med. I interpret it to happen for the period that my levels are increasing, and then it stops once things have stabilised (provided im not overmedicated). Curiously it happens in the evenings only (I take my dose on waking up). I've heard of thyroxine causing asthma type symptoms before. My compound pharmacist mentioned it as something her customers report.

Folate also helped me resolve my asthma. Specifically methylfolate or 5-MTHF. It should be taken with B12 because they work together. Recommend the methyl B12. In addition I have found magnesium to be helpful as well. I had asthma beginning at 14 years of age until about 7 years ago when I began taking methylfolate. If I feel any tightness in my chest now I up my magnesium which I guess helps to relax the muscles.

While definitely overdosed, I was diagnosed "hyperreactive bronchi". No asthma diagnosis, but coughing all the time. Much better when on less thyroxine.

Thanks. Were you v wheezy with it?It’s interesting to hear thyroid over and under dosing can have this effect ?

Thanks again

Also do any of you get itchy skin with over medicating? Or maybe it’s under treating?It’s so hard to work out which is causing the problem. I am getting tests done next week but need to address the asthma sooner so have cut the dose. Wonder if this means my test next week won’t be reliable ?

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