Can anyone help me understand how steroids aff... - Thyroid UK

Thyroid UK
109,259 members126,915 posts

Can anyone help me understand how steroids affect TSH?



I’ve been taking Levothyroxine since I had half my thyroid removed in Dec 2016, huge goitre.

My GP is one of the special ones who only look at TSH to adjust Levothyroxine because “the other readings don’t matter” 🤦🏻‍♀️ I also have very severe asthma and have used long term corticosteroids for all of my adult life (20yrs).

I read before somewhere that steroid will suppress you TSH and wondered if anyone here had any knowledge regarding that? It looks like that’s what is happening based on my latest results (see below) and I’d like to understand it better before I take my GP on.

TSH 0.22 mu/L [0.2-4.5]

FT4 9.9 pmol/L [9.0-24.0]

These are the only tests GP will do so I’m going to do the private full thyroid inc. T3 once Christmas is over to see what I’m converting to T3.

Thank you in advance xxx

15 Replies

Can't answer your question, but just to say make sure to also include testing vitamin D, folate, ferritin and B12 too

Hi Slowdragon,

Thanks for your reply. I have been tested for all the above and supplement Vit B12 and D, as well as folate. Ferritin is ok but serum iron is low (7.5umol/L [10.0-25.0]) so I have been referred back to Gastro for another Iron Infusion, last one was 14/02/2018.

NinjaKnitter xx

in reply to NinjaKnitter

So have you had endoscopy to look for reason for repeated low iron levels?

Have you had both TPO And TG thyroid antibodies tested?

If you need to regularly supplement all these to maintain levels it suggests you are inadequately treated for your hypothyroidism and/or Hashimoto's and/or gluten intolerance

What are actual B12, folate and vitamin D results and exactly what supplements do you take?

My low iron was blamed on heavy periods previously but that has been stopped by a mirena coil.

I have had thyroid antibodies checked and they were normal but I do still have the right lobe of my thyroid which is overgrown into a multinodular goitre. It was they smaller half, about 1/4 of the size of the right.

I’ve not had any further testing to see why I need to supplement and I’m currently taking:

Cyanocobalamin 50ug twice daily

Folic Acid 5mg once daily

Vitamin D 400IU twice daily

All are prescribed by GP I don’t have my levels to hand but can add them later. I do have IBS and wondered if this was affecting my ability to absorb properly.

I take 75mh Levothyroxine but my GP will not up it with a TSH of 0.22mu/L

NinjaKnitter xx

in reply to NinjaKnitter

Heavy periods are classic sign of being hypothyroid

You can have Hashimoto's and never have raised antibodies

Did you have both TPO and TG antibodies tested? Frequently NHSonly tests TPO

IBS is often gluten intolerance. Worth trying strictly gluten free diet after Christmas. Ideally do coeliac test first just to rule it out. Ask GP or buy online

Asthma can be made worse by dairy. Another thing to perhaps consider. Dairy intolerance or lactose intolerance pretty common with Hashimoto's

TSH is unreliable once on Levothyroxine. Especially if you have nodules and looks like steroids affect it too

You need FT3 and FT4 tested

All thyroid blood tests should ideally be done as early as possible in morning and fasting. Do not take Levothyroxine dose in the 24 hours prior to test, delay and take immediately after blood draw. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

Thank you so much for all of that. I already limit the amount of dairy I eat and have been tested for coeliac (negative). I will try eliminating gluten in the new year.

Once I’ve had the medichecks test results I’m going to request an endocrinologist referral and see if they can piece together the puzzle.

Thank you for all the tips, I really do appreciate it xx

Yes, I found when I was taking levothyroxin that if I also was taking a course of steroids, my TSH would be suppressed. The first time it happened, my GP didn’t believe that I was only taking my usual dose of thyroxine but when it happened the next time, he accepted that what I was saying was actually the case.


So I’m not imagining it then xxx

No, you’re not imagining it, lol!


Many drugs affect TSH levels including glucocorticoid steroids:

Best Pract Res Clin Endocrinol Metab. 2009 Dec; 23(6): 793–800.

doi: [10.1016/j.beem.2009.08.003]

PMCID: PMC2784889


PMID: 19942154


Bryan R. Haugen, MD, Professor of Medicine and Pathology

That’s brilliant. Thank you so much x

in reply to diogenes

Here's the link should anyone else want to read the paper:

Your free t4 is only just scraping over the bottom of the threshold, it might be worth pointing that out to the GP. I hope that you are listened to when you attend your appointment.

There are some studies that show that cortiscosteroids may cause central hypothyroidism perhaps by interfering with TRH in the hypothalamus:

Interesting. My husband is convinced that there is a pituitary link between all my conditions. Thank you xx

You may also like...