Blood test results show bad conversion? High fr... - Thyroid UK

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Blood test results show bad conversion? High free cortisol in 24 hour dried urine test

hashimomos profile image
24 Replies

Hi,

THYROID LABS

Here are my blood test results after being on 62.5mcg levothyroxine for 7 weeks:

- tsh decreased from 4 to 1.19 (0.27 - 4.2)

- ft4 increase from 17.7 to 20.7 (12 - 22)

- ft3 increase from 5 to 5.2 (3.1 - 6.8)

It looks like ft4 and tsh changed by 3 units but ft3 barely increased. Does this suggest bad conversion?

UPDATE: I was talking about this with     greygoose that I had an infection/flu (sore throat, stuffed nose) about 10-14 days before thyroid labs. While I was looking at the NHS Monitor My Health's website (monitormyhealth.org.uk/thyr... suggested by     tattybogle , I found:

"Being unwell can impact thyroid test results. We would recommend waiting 3 to 4 weeks after recovering from illness or infection before doing our thyroid tests."

I suspect this was the cause of my strange results but not entirely sure.

CORTISOL

I recently did a 24 hour cortisol urine test (before any infection/cold) and the report said:

"Overall free cortisol levels are elevated, but metabolized cortisol (the best marker for overall cortisol production) is within range. Cortisol clearance may be a bit sluggish, which keeps free cortisol levels elevated in spite of normal overall production."

"The patient shows significantly higher free cortisol compared to metabolized cortisol. It may be advisable to check thyroid hormones if you have not."

VITAMINS:

Active b12: >256 (25-165)

Methylmalonate (vit b12 marker): 1.0 (0 - 3.5) ; comments: within range, b12 deficiency less likely

25 OH Vit D: 69 (50 - 200)

Folate: 8 (>2.9)

[this was 9 weeks ago] Ferritin: 104 (30 - 400)

SYMPTOMS:

On 62.5mcg for 7 weeks,

Water retention (face, abdomen): I think water retention has very slowly improved on this dose until week 5 when I had a viral/flu infection. Then it stalled/regressed in the following weeks.

Weight: my weight increased on 50mcg levo from 66.7kg to 68kg. this came with water retention (see previous post). now, it's decreased back to around 66.5kg

Sleep: one of my main hypo symptoms (or probably secondary hypercortisol from hypo) is early morning awakenings. I simply cannot go back to sleep. Just like water retention, this improved (late awakenings), stalled and may have regressed in the end.

Temperature (oral): still never reaches 37c. Most of the day it sits at 36.3-36.6c. Compared to other people in the room, my hands and feet are cold to touch. During the infection, temps dropped below 36c.

Resting heart rate: low 50s

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hashimomos
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TiggerMe profile image
TiggerMeAmbassador

TSH 1.19 mIU/L (0.27 - 4.2) 23.4%

Free T4 (fT4) 20.7 pmol/L (12 - 22) 87.0%

Free T3 (fT3) 5.2 pmol/L (3.1 - 6.8) 56.8%

T4:T3 Ratio 3.981 

So your conversion rate isn't awful and might well be improved by optimizing your vit's and min's so it will be interesting to see those results

There is every chance that this dose will settle further and you'll need another increase, you are on a low dose, likely you'll need somewhere around 100mcg for your 68kg

Quite often cortisol levels resolves once thyroid levels are optimised

hashimomos profile image
hashimomos in reply toTiggerMe

Yea my conversion rate decreased drastically compared to the previous dose.

Why would the doc increase my dose if tsh is already around 1?

If I allow more time on 62.5mcg, do you think these markers could change further? I have already been on this dose for 50 days.

TiggerMe profile image
TiggerMeAmbassador in reply tohashimomos

I thought your Dr had prescribed 75mcg for you? 7 weeks is still early in the settling in period and as your body adjusts TSH will gradually start to climb again as it is slow to react then an increase is needed.... how are your symptoms? You'll start to feel cold and sluggish when levels lower

Possibly whilst on a lower dose your thyroid would still have been producing some hormone but as you add levothyroxine natural production ceases and conversion becomes essential

TiggerMe profile image
TiggerMeAmbassador in reply toTiggerMe

Dr's have a habit of signing you off for a year after testing too early before levels have settled leaving you Hypo

hashimomos profile image
hashimomos in reply toTiggerMe

Indeed i was presrcibed 75mcg but I couldn't sleep on it at all, so he switched me to 62.5mcg. I've been steady on that for 50 days now. Blood test was two days ago on Friday.

>7 weeks is still early in the settling in period and as your body adjusts TSH will gradually start to climb again as it is slow to react then an increase is needed.... how are your symptoms?

Wow! I had no idea TSH can drop first and then rise again. I would say my water retention slowly started decreasing from week 4. Then things slowed down after I had an infection. In this week, there's barely any progress.

TiggerMe profile image
TiggerMeAmbassador in reply tohashimomos

Some are very sensitive to dose change so increasing by 12.5mcg is not a bad idea, this can be linked in to your cortisol levels, you have likely plateaued on this dose, does he want you to retest in another 8 weeks?

It often takes the best part of a year to find your optimal dose

hashimomos profile image
hashimomos in reply toTiggerMe

How can it be linked to my cortisol levels?

My endo appointment is on Thursday

TiggerMe profile image
TiggerMeAmbassador in reply tohashimomos

Cortisol plays a role in getting the active fT3 into the cells, too much or too little effects this, cortisol has a circadian rhythm... this is often why some people prefer a before bed dose of Levo and others suit a first thing in the morning dose

Blood cortisol circadian rhythm
hashimomos profile image
hashimomos in reply toTiggerMe

my free cortisol levels according to the 24 hr test:

daily free cortisol pattern
TiggerMe profile image
TiggerMeAmbassador in reply tohashimomos

I'd suggest aiming to take your dose when you are within range, worth experimenting with, some find splitting the dose makes for a smoother ride

Have you results for folate, ferritin, B12 and Vit D as these being optimal helps with conversion?

hashimomos profile image
hashimomos in reply toTiggerMe

Good idea! I'm technically within range throghout the nightime (when cortisol is low) and above range in daytime. Also, iirc cortisol can decrease ft4 to ft3 conversion. So maybe taking it at bedtime is a better option for me?

I'll ask my doc :)

TiggerMe profile image
TiggerMeAmbassador in reply tohashimomos

4-6am seems to work for me, fine tuning tends to be something you need to experiment with as it is such a personal thing

humanbean profile image
humanbean in reply tohashimomos

Indeed i was presrcibed 75mcg but I couldn't sleep on it at all, so he switched me to 62.5mcg.

In your shoes I would have continued with the prescription of 75 mcg but reduced what I took to 62.5 mcg myself if it was possible to cut the pills I received to create that dose. With Levo it is also possible to create a particular dose by taking different doses on different days.

For example, I take on average 85.7 mcg Levo per day, and I achieve this by taking 50mcg Levo on Monday and Thursday, and take 100mcg Levo the other days of the week.

It works for me, but I know it doesn't always work for others to have different doses on different days.

The reason I suggest doing this is that by continuing to be prescribed 75mcg per day while taking 62.5mcg per day you could have built up a small amount of Levo to experiment with your dose and how you take it.

Doctors don't usually approve of this, but I'm the person putting the Levo in my mouth and living in my body, and I'm not going to accept a doctor micro-managing my thyroid hormone intake! I'm perfectly capable of doing that myself.

helvella profile image
helvellaAdministrator

Count me out when it comes to cortisol - I feel I know nothing.

But I dose levothyroxine at bed-time. And I have written a blog linking to multiple experiences of doing so. Works for some; doesn't work for others.

helvella - Bed-time dosing of levothyroxine

Discussion about taking levothyroxine at bed-time. Several linked references to relevant papers.

Last updated 12/02/2025

Link to blog:

helvella.blogspot.com/p/hel...

hashimomos profile image
hashimomos in reply tohelvella

Thanks but what do you think of the thyroid labs?

SlowDragon profile image
SlowDragonAmbassador

Suggest you experiment with taking Levo at bedtime

If this keeps you awake try splitting as half in morning and half at bedtime

Retest again in another 6-8 weeks likely to see TSH increased and Ft4 dropped a bit

Likely ready for next increase by then

Which brand of Levo are you taking

Need to see vitamin results obviously

What vitamin supplements are you taking

Are you on gluten free diet and/or dairy free diet

hashimomos profile image
hashimomos in reply toSlowDragon

hi, just updated my whole post. pls take a look!

tattybogle profile image
tattybogle

hi , i know next to nothing about cortisol, so can't offer any enlightenment there

but first , see what your vits are like ... don't underestimate their importance in helping everything including thyroid hormones to work efficiently . my 26yr old daughter who is otherwise fit / healthy has recently been found to be deficient in B12 and extremely low in ferritin and folate, despite eating a pretty good diet , which explains why she's been struggling to function properly in the last year / longer .

re the thyroid hormones , it is quite possible your TSH will rise again , and / or t4/t3levels change once you've been on 62.5 for a few months longer, everything takes a long time to readjust itself .

i would retest TSH / FT4/FT3 in another 2 or 3 months to see if anything changed,, do it privately if GP won't. Monitor My Health (NHS lab postal service) is only about £30

if your vit's turn out to be pretty good ( post on here for evaluation ,advice on how to improve) , i would be inclined to increase dose now to the 75mcg , and see how that goes .

if they need work , i'd stay on 62.5mcg for now while you work on them , and then re-asses T4/T3 TSH once they have improved .

it's a long game of 'get your ducks in something like a row,, then wait to see how they perform .. then get them back in row ,, then wait to see' etc etc .

hashimomos profile image
hashimomos in reply totattybogle

hi, just updated my post with vits!

Sleepman profile image
Sleepman

You have not really said how you are feeling and what symptoms are like. Hope you have ducked the nasty winter lurgies.

If autoimmune it is probably too early to start worrying about conversion of T4 to T3.

You have 2 T3s over 50% which I never got anywhere near at the start.

Well done for getting vit and minerals blood test.

As everyone above get these levels optimised next.

Temperature does not look too bad - did you have any readings from before levo.

I just took first thing in a morning and tracked that - there is some science behind that but cannot remember the details of it. It is more complex for females as they have a 28 day cycle.

I am going to read Helvella's blog - I struggle to get going these days and consider night time dose trial.

Let us know what your endo advises.

hashimomos profile image
hashimomos in reply toSleepman

hi, just updated my whole post. pls take a look!

jimh111 profile image
jimh111

This is quite normal, the body acts to preserve fT3 with conversion rate varying according to fT4 levels. Like most people your conversion rate is fine but treatment would depend upon your signs and symptoms. Do you still have substantial symptoms of hypothyroidism?

hashimomos profile image
hashimomos in reply tojimh111

hi, just updated my whole post. pls take a look! I mentioned the symptoms too

jimh111 profile image
jimh111 in reply tohashimomos

Your symptoms seem quite mild, unless you've understated them. Body temperature isn't much use for diagnosing hypothyroidism as we all have different natural levels. Have you checked for iron deficiency?

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