Thyroid results - advice please : Hi all, I... - Thyroid UK

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Thyroid results - advice please

mistygrey profile image

Hi all, I wanted to check my results to see what people think. I’m on 100mcg T4 and 5mcg Liothyronine T3 daily my recent results are below. I’ve been feeling extremely wiped out and breathless on occasions. My iron levels are fine I had them done also. Do my thyroid levels look like there is room for improvement? I am not sure what to increase if anything, higher doses of T3 did give me palps for some reason. Thanks for any advice given.

FT4 16 range 9-21

FT3 4.3 range 2.4-6

TSH 0.55 range 0.2-4.5

18 Replies
SlowDragon profile image

Was this test done as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test. Last 2.5mcg T3 approx 8-12 hours before test

Result suggests under medicated

Please add most recent vitamin D, folate, ferritin and B12 results

Have you tried adding 2nd 5mcg dose T3 approx 10-12 hours after first dose?

Approx how much do you weigh in kilo

Guidelines on dose levothyroxine by weight is approx 1.6mcg levothyroxine per kilo per day when on LEVOTHYROXINE ALONE

mistygrey profile image
mistygrey in reply to SlowDragon

Hi thank you for your reply. The bloods were done faster and I had my last dose of levothyroxine 24 hrs before as you mentioned and last dose of T3 was 5pm the day before.

I am 12 stones in weight. What would be best to increase if I am under medicated, I remember on higher doses of T3 I felt palps so I am not sure if that’s going to work but I am open to trying whatever would be best. Not due to see my consultant until end of Nov now. Thank you

SlowDragon profile image
SlowDragonAdministrator in reply to mistygrey

So were you on higher dose levothyroxine before T3 was added?

mistygrey profile image
mistygrey in reply to SlowDragon

No before T3 I was only on 75mcg and very ill

SlowDragon profile image
SlowDragonAdministrator in reply to mistygrey

Hardly surprising as 75mcg is only one step up from starter dose

What were your results on just 75mcg levothyroxine

guidelines on dose levothyroxine by weight

Even if we frequently don’t start on full replacement dose, most people need to increase levothyroxine dose slowly upwards in 25mcg steps (retesting 6-8 weeks after each increase) until eventually on, or near full replacement dose

NICE guidelines on full replacement dose


Consider starting levothyroxine at a dosage of 1.6 micrograms per kilogram of body weight per day (rounded to the nearest 25 micrograms) for adults under 65 with primary hypothyroidism and no history of cardiovascular disease.

Also here

Traditionally we have tended to start patients on a low dose of levothyroxine and titrate it up over a period of months. RCT evidence suggests that for the majority of patients this is not necessary and may waste resources.

For patients aged >60y or with ischaemic heart disease, start levothyroxine at 25–50μg daily and titrate up every 3 to 6 weeks as tolerated.

For ALL other patients start at full replacement dose. For most this will equate to 1.6 μg/kg/day (approximately 100μg for a 60kg woman and 125μg for a 75kg man).

If you are starting treatment for subclinical hypothyroidism, this article advises starting at a dose close to the full treatment dose on the basis that it is difficult to assess symptom response unless a therapeutic dose has been trialled.

BMJ also clear on dose required

12 stone = 76 kilo

76 x 1.6 = 121mcg as likely daily dose levothyroxine required

So on JUST LEVOTHYROXINE you were likely to need 125mcg daily, or perhaps 125mcg 6 days week and 100mcg 1 day week

Perhaps try increasing levothyroxine from 75mcg daily to 75mcg and 100mcg alternate days. Retest thyroid and vitamin levels in 6-8 weeks time

mistygrey profile image
mistygrey in reply to SlowDragon

Hi thanks for this, currently I am on 100mcg T4 and 5 much t3 so what would be the best increase in dose for that dosage? 75mcg was my previous dose a year ago and I’m not on that dose now. Thank you

SlowDragon profile image
SlowDragonAdministrator in reply to mistygrey

How do you feel

Do you feel well, or under medicated

What vitamin supplements are you currently taking

What are your most recent vitamin D, folate, ferritin and B12 results

Are you on absolutely strictly gluten free diet?

Or tried it

mistygrey profile image
mistygrey in reply to SlowDragon

I have been feeling exhausted lately but I also have rheumatoid arthritis so it’s hard to know between the two what’s causing what. But my results for my thyroid do look like there is some room for improvement, I’m just not sure what dose to try or if it’s worth trying a dose change. I am gluten free and dairy free, I also get b12 injections and take vitamin D. My ferritin wasn’t too low on the recent test it is usually much lower so I had thought the iron maybe was low but it didn’t look to be recently.

SlowDragon profile image
SlowDragonAdministrator in reply to mistygrey

How low?

Vitamin D at least around 100nmol

Serum B12 over 500

Folate and ferritin at least half way through range

Perhaps try 2nd dose T3

What time did you have your blood test? Last T3 should be 8 - 12 hours before. If you left longer than that, your FT3 will show a false low.

Hi I had the bloods taken fasted first thing in the morning around 8 am. Last dose of T4 is as the day before at 8 am last dose of T3 was at 5pm day before

So there was a gap of 15 hours so your FT3 is a false low. If it was me, I would try an increase in Levo first, perhaps 12.5 mcg and see how you feel then. That will raise both your FT4 and FT3. It’s all trial and error unfortunately.

Thank you. Yes you are right, I think that’s great advice and I did think that might be a good starting point increasing the T4 by 12.5 as my T4 pills are 25mcg already so the 12.5 would be easy to do but just splitting the pill. Thank you for your advice

Stourie profile image
Stourie in reply to Gingernut44

Just asking but if there’s a window of 4hours for a t3 test from 8 to 12 hours why couldn’t it be from say 11 to 15 hours. Jo xx

Gingernut44 profile image
Gingernut44 in reply to Stourie

Well, as far as most info I’ve seen, T3 peaks in the blood about 6 hours after taking it so 12 hours seems to be the longest you should leave before a blood test. Of course, consistency is the key. I’m no medic, only passing on my own understanding 🙂SlowDragon will be more knowledgeable than me to answer your question.

Stourie profile image
Stourie in reply to Gingernut44

Thank you. Jo xx

How long does the 12.5mcg T4 increase take to start working or start feeling I’ve taken this increase so you know? Thank you

I’m afraid I can’t answer that. Everyone is different. All you can do is try, see how you feel and get your bloods done in 6/8 weeks and go from there. Good luck.

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