Is there a ‘common’ T4:T3 ratio: As in, I’ve lost... - Thyroid UK

Thyroid UK

137,716 members161,494 posts

Is there a ‘common’ T4:T3 ratio

Murphysmum profile image
15 Replies

As in, I’ve lost my way!

If I’m now taking 50mcg T3, is there a reasonably common dose of levo that people take? This is difficult to explain but I gradually increased my T3 and dropped my levo in stages. Then, once my levo seemed to be within range but at the lower end, I left it at that level and continued to increase T3. I now realise this was probably a mistake but hey.

Recently I dropped the levo completely and felt great for around 6 weeks but then reintroduced a tiny amount as it seems to keep me more stable.

I’m now experimenting with lowering my T3 dose a bit as I think I many have missed a sweet spot somewhere along the way.

Hence my question. I don’t want to reintroduce too much levo as it clearly wasn’t helping at a higher level, but if I’m dropping T3, will I leave myself low across the board by not putting in a bit more levo? Or do I just trial the T3 levels and not change the levo at all? ( I would only change one thing at a time anyway)

Sorry, probably clear as mud but I’ve got my self confused! Not surprising really!

And on a side note... what causes head pressure? Do we know? Or it it just “low” hormone in general?

TIA 😊

Written by
Murphysmum profile image
Murphysmum
To view profiles and participate in discussions please or .
Read more about...
15 Replies
fuchsia-pink profile image
fuchsia-pink

50 mcg of T3 is a high dose.

There doesn't seem to be a clear consensus on how much T4 equals how much T3 - but I would suggest reducing T3 say 1/4 of a tablet at a time and adding levo at the same time, working on 10 mcg of T3 = 40 to 50 mcg of T4 ... and stay like that for a couple of weeks; then repeat as necessary. When you find a good place for you, stay on that dosage for 8 weeks and do full blood testing.

greygoose profile image
greygoose

Ratios are for healthy people. Hypos need what they need, and those needs vary from person to person. Personally, I cannot tolerate any T4 at all. Others need quite a high FT4 even when they're taking T3. You have to find what you need by trial and error.

Then, once my levo seemed to be within range but at the lower end, I left it at that level and continued to increase T3. I now realise this was probably a mistake but hey.

Why do you think that was a mistake? It might be just what you need. How do you feel? How you feel should be what guides you, not ratios. :)

Murphysmum profile image
Murphysmum in reply to greygoose

Thankyou.

I agree but as I say, I’ve got a bit confused with it!

Although the T3 has made a massive difference to me undoubtedly, I couldn’t shift the aching joints, frozen shoulder etc. Then I decided to stop the levo and boom, I felt almost instantly (within a couple of days) better.

However, after about 6 weeks I found that the peaks and troughs of T3 were more pronounced - the troughs specifically- so introduced a little levo. It seems to have helped.

I had got to 70mcg T3 but this seemed too much. I spent an evening three days after the increase with a rapid heart rate and just feeling very uncomfortable. That has inspired me to try reducing as when I felt best was on 25/30mcg with hindsight. As I’ve increased so the muscle weakness has reappeared and never been improved with further increasing. Also, my eyesight was much worse. A weird blurriness particularly after using my phone that would start after a few minutes and last for ages. This has stopped with a reduction. The muscle weakness remains.

I guess my problem is I’m not quite sure what to try next. Do I remain at 50mcg for a while and try adding in a little more levo? Do I leave the levo the same and decrease the T3 a bit more in which case how do I know if it’s the effects of low T3 or low T4 I’m feeling? 🙈

See what I mean! Totally confused! 😂

greygoose profile image
greygoose in reply to Murphysmum

As SeasideSusie says, it's probably better to retest before changing anything. :)

experimental1 profile image
experimental1 in reply to greygoose

greygoose,

I'm always impressed by your analysis. Regarding ratios, which I only pay scant attention to, I've yet to read of anyone taking a 1 to 1 ratio of t3/t4, if one can tolerate t4. For some of us who are serious outliers, the so called rules become an impediment and sometimes, irrelevant.

greygoose profile image
greygoose in reply to experimental1

Totally agree with you. They do.

SeasideSusie profile image
SeasideSusieRemembering

Everyone is different so there's no common ratios of Levo to T3. I am currently taking 8:1 which, for some people, would be far too much Levo and not enough T3, but it suits me because I've discovered by trial and error that I need both FT4 and FT3 to be around 75% through range to feel best and that ratio currently gives me that. Others do fine with a low FT4 and FT3 in the upper part of the range so they make take less Levo and more T3. Some find that T3 only is best for them.

Have you tested as you've changed doses? Do you have any results where you were feeling OK and do you know your doses of Levo and T3 at that time?

Murphysmum profile image
Murphysmum in reply to SeasideSusie

Well when I felt best (as I recall!) I was on 50mcg levo and 25mcg T3.

The muscle weakness was gone and I felt full of energy. However, I had crippling joint pain and the frozen shoulder. The joint pain disappeared around then but the shoulder remained until I stopped levo. I felt.. lighter all over with the removal of the levo but as I say I seemed to dip a lot in between T3 doses. The addition of a little levo seems to have stopped that.

I didn’t do any more bloods after I was at 50/25 as at that point I was top of the range for T3 and low but within range for T4. I figured once I increased I’d be over range so I just concentrated on how I felt. Bloods maybe would’ve given me a better record though.

Is it worthwhile doing some now to give me an idea? Even if they are out with the ranges?

SeasideSusie profile image
SeasideSusieRemembering in reply to Murphysmum

It might be a good idea to test now - as long as it's 6-8 weeks since any dose change. The results will give you a sort of baseline to work from for future changes of dose. Keep a record of doses and how you feel so that you can look back and compare.

Remember the golden rules when doing thyroid tests so that you get accurate results every time so that you can compare:

* Book the first appointment of the morning, or with private tests at home no later than 9am. This is because TSH is highest early morning and lowers throughout the day. If we are looking for a diagnosis of hypothyroidism, or looking for an increase in dose or to avoid a reduction then we need TSH to be as high as possible.

* Fast overnight - have your evening meal/supper as normal the night before but delay breakfast on the day of the test and drink water only until after the blood draw. Eating may lower TSH, coffee affects TSH so it's possible that other caffeine containing drinks may also affect TSH.

* If taking thyroid hormone replacement, last dose of Levo should be 24 hours before blood draw, if taking NDT or T3 then last dose should be 8-12 hours before blood draw. Adjust timing the day before if necessary. This avoids measuring hormone levels at their peak after ingestion of hormone replacement. Take your thyroid meds after the blood draw. Taking your dose too close to the blood draw will give false high results, leaving any longer gap will give false low results.

* If you take Biotin or a B Complex containing Biotin (B7), leave this off for 7 days before any blood test. This is because if Biotin is used in the testing procedure it can give false results (most labs use Biotin in the assay).

These are patient to patient tips which we don't discuss with doctors or phlebotomists.

How are you nutrient levels? Low Vit D can give muscle and joint aches and pains. Nutrient levels should be optimal when we add T3. If not already tested then I'd check

Vit D

B12

Folate

Ferritin

Both Medichecks and Blue Horizon do a thyroid/vitamin bundle - Medichecks is Thyroid Check Plus ULTRAVIT and Blue Horizon is Thyroid Check PLUS ELEVEN. You can use code THYROIDUK for a 10% discount with Medichecks on any test not already on special offer.

When you do change your doses, only change one at a time - either Levo or T3 - not both together. You need to know which hormone is making a difference and you can't know that if you change doses of both at the same time. Give 6-8 weeks after a dose change for levels to stabilise before retesting.

Murphysmum profile image
Murphysmum in reply to SeasideSusie

I think my nutrients should be quite good but I am due to test them.

You have spurred me on to do it! Thanks.

SlowDragon profile image
SlowDragonAdministrator

Personally I have found after almost 2 years experimenting on dose and timing ....

always same brands of Levothyroxine (MP) and T3 (Morningside)

20mcg T3 - as 10mcg 7am, 5mcg at 3pm and 5mcg at 11pm

Plus split dose levothyroxine 100mcg at 11pm and 25mcg at 7am

That gives high, but within range Ft4 and high Ft3

.....and I think each dose change needs to be held at for at least 8-10 weeks

Murphysmum profile image
Murphysmum in reply to SlowDragon

thats interesting re your 3x split.

I haven't tried this - do you recall why you chose to add in a late dose at night? What symptoms were you having?

I'm most active in the morning usually. I feel quite often I've probably used my T3 dose up long before its next due. increasing the split i.e., 40/20mcg for example didn't seem to make any odds. I usually feel better in the afternoon compared to the morning but will get skipped/crazy heart beats in the evening. (this has ben more prevalent again recently with a lower dose... I'm keeping an eye)

I'm tempted to reread and try the CT3M protocol but I really don't fancy waking up stupidly early!

There isn't really a common ratio. It's a highly individual thing. You'll see some websites saying that ther is a certain figure, but that's an average - usually taken from some research by Pilo, which actually showed that there there was huge individual variation among healthy people - it's a bit saying that there is an average dress size, so a dress in that size will fit anyone. 50mcg T3 is not a particularly high dose if you are on T3 only, but it's a lot if you are also taking levo. I find that if my FT4 drops too far under range, I feel bad so I take a grain of NDT to boost it a bit (very unscientific). Other people find that they feel well with an FT4 of near 0.

Murphysmum profile image
Murphysmum in reply to Angel_of_the_North

Thanks.

My levo dosing is bordering on the non-scientific now but hey, if it works!

Just need to work out T3 (I think). Too high or too low now.. I’m just not sure.

I’ll keep tweaking I think. We’ll get there eventually...

LAHs profile image
LAHs

As others have said above, our needs are very individual however in answer to your question the usual human ratio is 4:1 or 3:1 i.e. it takes 4 (or 3) molecules of T4 to generate 1 molecule of T3.

Oh, and watch your units if you are working this out from scratch, they have to be the same.

You may also like...

T3/T4 ratio dosing query

have now upped my T3 dose to one and a half Tiromel 25mcg tablets whilst also taking 50mcg Levo I...

T4:T3 ratio test results

the actual measurements (especially the T4) seem a little low though in range. The results are...

T4 to T3 conversion ratio

Is there a T3 to T4 ratio

thyroidectomy for papillary thyroid cancer and on Levo only. I always get my FTF blood results in a...

Help with appropriate T4/T3 ratio and levels in lab results

places the highest importance on T3 levels, and argues that T4 levels do not correlate well with...