Latest thyroid tests - T3 dropped

[Cat_bluenote]

Hi everyone, I increased from 50 to 62 mcg of Levothyroxin 7 weeks ago. Latest private thyroid tests, below . Just wondering why my T3 conversion has dropped a fair bit? 4/4/24

TSH - 3.55 (0.27 - 4.2)

T4. - 16.3 (12 -22)

T3. - 4.3. (3.1 -6.8)

14/2/24

TSH. - 4.74. (0.27. - 4.2)

T4. - 16.5. (12-22)

T3 - 5.1. (3.1 -6.8)

I 've noticed an improvement in mood and energy. Seeing Endo later this week, hoping for further increase.

[SlowDragon Administrator]

Yes you are ready for next increase in dose

75mcg daily

Which brand of levothyroxine are you taking

Always same brand

Retest again in another 8 weeks

Ft4 not risen at all with last, very conservative and too small an increase in dose Levo

Likely to need further increase after going to 75mcg daily

Retest vitamin levels twice year

Last test results look pretty good

healthunlocked.com/thyroidu...

[Cat_bluenote in reply to SlowDragon]

Hi, I'm taking 50 mcg Accord and 25 Wockhardt. I'm self medicating. So whilst waiting to see Endo (because GP refuses increase) I thought I'd go ahead and try a small increase with extra tablets I had in. Thanks for your reply

[SlowDragon Administrator]

Guidelines of dose Levo by weight

approx how much do you weigh in kilo

Even if we frequently start on only 50mcg, 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

pathlabs.rlbuht.nhs.uk/tft_...

Guiding Treatment with Thyroxine:

In the majority of patients 50-100 μg thyroxine can be used as the starting dose. Alterations in dose are achieved by using 25-50 μg increments and adequacy of the new dose can be confirmed by repeat measurement of TSH after 2-3 months.

The majority of patients will be clinically euthyroid with a ‘normal’ TSH and having thyroxine replacement in the range 75-150 μg/day (1.6ug/Kg on average).

The recommended approach is to titrate thyroxine therapy against the TSH concentration whilst assessing clinical well-being. The target is a serum TSH within the reference range.

……The primary target of thyroxine replacement therapy is to make the patient feel well and to achieve a serum TSH that is within the reference range. The corresponding FT4 will be within or slightly above its reference range.

The minimum period to achieve stable concentrations after a change in dose of thyroxine is two months and thyroid function tests should not normally be requested before this period has elapsed.

TSH should be under 2 as an absolute maximum when on levothyroxine

gponline.com/endocrinology-...

Graph showing median TSH in healthy population is 1-1.5

web.archive.org/web/2004060...

Comprehensive list of references for needing LOW TSH on levothyroxine

healthunlocked.com/thyroidu....

onlinelibrary.wiley.com/doi...

If symptoms of hypothyroidism persist despite normalisation of TSH, the dose of levothyroxine can be titrated further to place the TSH in the lower part of the reference range or even slightly below (i.e., TSH: 0.1–2.0 mU/L), but avoiding TSH < 0.1 mU/L. Use of alternate day dosing of different levothyroxine strengths may be needed to achieve this (e.g., 100 mcg for 4 days; 125 mcg for 3 days weekly).

[Cat_bluenote in reply to SlowDragon]

Hi, thanks for all the useful information. I'm 52 kg, I'm hoping Endo will increase me to 75mcg when I see them this week.

[SlowDragon Administrator in reply to Cat_bluenote]

Currently taking

62.5mcg daily = 437.5mcg per week

52kg x 1.6mcg = 83.2mcg

582.5mcg per week

So 75mcg will be getting nearer

75mcg per day is 525mcg per week

[Cat_bluenote in reply to SlowDragon]

Thank you so much

[SlowDragon Administrator in reply to Cat_bluenote]

Might need another small increase after that

Eg

87.5mcg x 4 days and 75mcg x 3 days = 575mcg per week

Or

87.5mcg x 5 days and 75mcg x 2 days = 587mcg per week

[Cat_bluenote in reply to SlowDragon]

Thanks. Just wondering, if I were to take 575mcg weekly, would it matter if it was 75 mcg x 5 days and 100mcg x 2 days? Or is it better for your body if the daily amount is more similar like in your example?

[SlowDragon Administrator in reply to Cat_bluenote]

Some people are fine on different doses per day

Some people find it better to take same or similar doses every day

In theory levothyroxine is a storage hormone and it shouldn’t make any difference

Best to stick to same brand levothyroxine if possible