Why is t3 low while tsh is also low?

[SarahLou30]

Hi all, I am looking for insight before talking to my endo again next week. My tsh has continually been dropping over the past couple years, but the last year it has been dropping quicker even with lowering my synthroid dose every two months or so. I have had Hashimotos hypothyroidism since I was around 10 and have never been on such a low dose. I’m on 100 mcg now, but I’ve been up to 200 before in the past. Weirdly, my t3 is too low, though, so I’m a combo of hypo and hyper right now.

Tsh: .2 (.27-4.2)

Free t3: 1.7 (2.3-4.2)

Free t4: 1 (.9-1.8)

I’ve also been losing weight this past year (about 15 pounds down to 120) and I haven’t had my period in three months. Im 33 years old. I’ve cut back a little on caloric intake (maybe 300 cald per day this year), but that doesn’t seem like enough to have such a large weight loss. Additionally I have had mildly elevated pancreas enzymes for a few years. My gi doctor is having me get an mri of my pancreas to rule out a carcinoid tumor. I just feel like there’s something else wrong that no one is picking up on, and I’m struggling to know how to advocate for myself with my endo.

My symptoms: chronic dyspnea that’s worse with exertion, dry skin, sleep disturbances- lots of wake ups, cold all the time, and constipation.

Thank you so much for any feedback in advance.

Sarah

[SlowDragon Administrator]

Low Ft3 leads to low vitamin levels

Low vitamin levels tend to lower TSH

Your results suggest you are very under medicated and very poor conversion of Ft4 to Ft3

Ft3 is BELOW RANGE

Ft4 is right at bottom of range

The aim of levothyroxine is to increase dose upwards until Ft4 is in top third of range and Ft3 at least half way through range (regardless of how low TSH is)

Extremely important to have optimal vitamin levels too as this helps reduce symptoms and improve how levothyroxine works

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also EXTREMELY important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially as you have Hashimoto’s

There’s current ludicrous obsession to treat by TSH, this frequently leaves patients woefully under medicated

Ask GP to test vitamin levels

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

Is this how you do your tests?

Private tests are available as NHS currently rarely tests Ft3 or thyroid antibodies or all relevant vitamins

List of private testing options

thyroiduk.org/getting-a-dia...

Medichecks Thyroid plus antibodies and vitamins

medichecks.com/products/adv...

Thriva Thyroid plus antibodies and vitamins By DIY fingerpick test

thriva.co/tests/thyroid-test

Thriva also offer just vitamin testing

Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins by DIY fingerprick test

bluehorizonbloodtests.co.uk...

If you can get GP to test vitamins and antibodies then cheapest option for just TSH, FT4 and FT3

£29 (via NHS private service ) and 10% off down to £26.10 if go on thyroid uk for code

thyroiduk.org/getting-a-dia...

monitormyhealth.org.uk/

Also vitamin D available as separate test via MMH

Or alternative Vitamin D NHS postal kit

vitamindtest.org.uk

As you have Hashimoto’s are you on strictly gluten free diet or dairy free diet....or tried either

[SarahLou30 in reply to SlowDragon]

Thank you so much for the extremely helpful information. I am strictly gluten free but I eat dairy (cottage cheese and greek yogurt everyday). I have an extremely limited diet due to an allergic condition called mast cell activation syndrome and mainly eat fruits, veggies, quinoa, one egg a day, and dairy. I will ask to get vitamin levels checked but when I have had them checked before, they’ve been normal (except vitamin d which is around 30).

I’m worried that if I get on t3, my tsh will drop too low. my endo won’t put me on t3 until she says that my tsh is higher, so she keeps lowering my synthroid dose. It’s all very frustrating. Thank you so much again.

[SlowDragon Administrator in reply to SarahLou30]

You need a new endocrinologist if all they are looking at is TSH

As a Hashimoto’s patient with food intolerances you are going to have poor conversion of Ft4 to Ft3

Presumably you are in USA?

Looking for vitamin D at least around 40ng/ml minimum

[greygoose]

I’ve cut back a little on caloric intake (maybe 300 cald per day this year), but that doesn’t seem like enough to have such a large weight loss.

So, around how many calories are you getting a day, now? If you cut back too far, that will affect your conversion of T4 to T3 - which is what seems to have happened to you. You need calories to convert! Try putting your intake back to what it was before, and see if that helps. Weight-loss can be a hypo symptom just like weight-gain.

[SarahLou30 in reply to greygoose]

Thanks so much for your response! I’m getting about 2,000 calories a day which should be enough. I’m 120 pounds and about 5’6. I didn’t know that weight loss can be a sign of hypothyroidism as well. That’s good to know.

[greygoose in reply to SarahLou30]

Yes, 2000 should be good. So, perhaps it's low nutrients causing your reduced conversion.