T3 dose advice

[Josephine63]

Hi,

Hoping for some advice/guidance from the experts on here:

Currently taking 75mcg levothyroxine and 10mg T3 (5mg 2 x daily)

Feeling much better than before started on T3 (August 2024)

In March 2025:

TSH 0.02 (0.27 - 4.2)

Thyroxine 16.9 (12 - 22)

T3 4.2 (3.1 - 6.8) highest was 4.6 (3.1 before started T3)

Ferritin 98

Active B12 66

Folate 7.6

Vitamin D 92

All blood tests taken before 9 in the morning before taking meds, 24 hours after last T4 dose and 10 hours after last T3 dose.

As mentioned, before starting on T3 last year, I was very lethargic, napping during the day, sleeping too long etc. I feel much better, but still have some tiredness and still flag when exercising, which I do regularly - get a bit breathless too (Hb level is good).

I think my T3 level could still be higher - I have noticed on other posts, there are recommendations for it to be in the upper part of the normal range. Shall I increase my T3? If so, how much should I add to the 2 daily doses please? Do I then decrease my T4? If so, by how much please?

I have seen, on here, discussions about not worrying about the very low TSH. I have had my blood tests taken privately and was put on T3 by endo. I think that I only need to worry about the low TSH if the GP questions this if I request a T3 dose change, and they arrange a blood test?

Cholesterol: my cholesterol, as expected has decreased since taking T3. Total cholesterol is 6.1, but HDL was 1.98, non-HDL was 4.42 so ratio is 3.23/1 which is good. Have tried several statins and an injectable and all give me severe aches and make be feel ill, so would prefer not to take any of these. Any advice here?

Many thanks for all your help.

[SlowDragon Administrator]

Free T4 (fT4) 16.9 pmol/L (12 - 22) 49.0%

Free T3 (fT3) 4.2 pmol/L (3.1 - 6.8) 29.7%

Results suggest that you are not on high enough dose

You could either increase Levo to 87.5mcg daily

Or

Increase T3 to 3 x 5mcg daily

Retest in 6-8 weeks time

B12 and folate on lower side

What B vitamins are you taking

IMPORTANT......If you are taking vitamin B complex, or any supplements containing biotin, remember to stop these 3-5 days before ALL BLOOD TESTS , as biotin can falsely affect test results

endocrinenews.endocrine.org...

In week before blood test, when you stop vitamin B complex, you might want to consider taking a separate folate supplement (eg Jarrow methyl folate 400mcg) and continue separate B12 if last test result serum B12 was below 500 or active B12 (private test) under 70

Did you do this?

[Josephine63 in reply to SlowDragon]

Excellent! Thank you so much, SlowDragon, for your advice. I will increase T3 tomorrow by adding a third 5mg dose.

I do not take any vitamins at all. What would you recommend please?

Thank you!

[SlowDragon Administrator in reply to Josephine63]

Which brand of T3 have you got

What size tablets

[Josephine63 in reply to SlowDragon]

From the gp, I was given Morningside Liothyronine 10mg to half, then a 5mg tablet for which I have disposed of the box - says Strides Pharma UK Ltd on the strip. I have a microscales and pill cutter for when I use the 10mg.

[SlowDragon Administrator in reply to Josephine63]

I do not take any vitamins at all.

Vitamin D surprisingly good then

Are you in the U.K.?

B12 and folate

With serum B12 result below 500, (Or active B12 below 70) recommended to be taking a separate B12 supplement

A week later add a separate vitamin B Complex 

Then once your serum B12 is over 500 (or Active B12 level has reached 70), you may be able to reduce then stop the B12 and just carry on with the B Complex.

If Vegetarian or vegan likely to need ongoing separate B12 few times a week

Highly effective B12 drops

natureprovides.com/products...

Or

B12 sublingual lozenges

uk.iherb.com/pr/jarrow-form...

cytoplan.co.uk/shop-by-prod...

In-depth article on different forms of B12

perniciousanemia.org/b12/fo...

B12 range in U.K. is too wide

Interesting that in this research B12 below 400 is considered inadequate

healthunlocked.com/thyroidu...

perniciousanemia.org/b12/le...

And why aiming to keep B12 over 500 recommended

perniciousanemia.org/b12/le...

Great reply by @humanbean on B12 here

healthunlocked.com/thyroidu...

Low folate

supplementing a good quality daily vitamin B complex, one with folate in (not folic acid)

This can help keep all B vitamins in balance and will help improve B12 levels too

Difference between folate and folic acid

healthline.com/nutrition/fo...

Many Hashimoto’s patients have MTHFR gene variation and can have trouble processing folic acid supplements

thyroidpharmacist.com/artic...

B vitamins best taken after breakfast

Igennus B complex popular option. Nice small tablets. Most people only find they need one per day. But a few people find it’s not high enough dose and may need 2 per day and/or may need separate methyl folate couple times a week

Post discussing different B complex

healthunlocked.com/thyroidu...

Thorne Basic B recommended vitamin B complex that contains folate, but they are large capsules. (You can tip powder out if can’t swallow capsule) Thorne can be difficult to find at reasonable price, should be around £20-£25. iherb.com often have in stock. Or try ebay

[Josephine63 in reply to SlowDragon]

Yes, in the UK! And sorry, I forgot that I take Vit D on prescription - invita D3 800mg daily. Thank you for all the vitamin info - I will read through all of that and order some.

[Josephine63 in reply to SlowDragon]

Oh, and not vegetarian or vegan, but hardly eat any meat - probably haven't eaten meat in 2025! Eat fish and seafood. And have a gluten free diet. Very little dairy and lactose free milk.

[SlowDragon Administrator in reply to Josephine63]

Very little dairy and lactose free milk.

So which brand is your Levo ?

Both Levo and T3 both need to be lactose free as well

I was given Morningside Liothyronine 10mg to half, then a 5mg tablet for which I have disposed of the box - says Strides Pharma UK Ltd on the strip. I have a microscales and pill cutter for when I use the 10mg.

Morningside is not lactose free

Not sure about Strides

Lactose free T3 options

20mcg

On NHS prescription - Teva

Private prescription - Thybon Henning

5mcg

Sigma Pharma……but I think this may also contain mannitol

[SlowDragon Administrator]

Cholesterol: my cholesterol, as expected has decreased since taking T3. Total cholesterol is 6.1, but HDL was 1.98, non-HDL was 4.42 so ratio is 3.23/1 which is good. Have tried several statins and an injectable and all give me severe aches and make be feel ill, so would prefer not to take any of these. Any advice here?

Well statins not recommended for thyroid patients and as you said cholesterol is dropping and will drop further once on optimal thyroid hormone replacement

nhs.uk/conditions/statins/c...

If you have an underactive thyroid (hypothyroidism), treatment may be delayed until this problem is treated. This is because having an underactive thyroid can lead to an increased cholesterol level, and treating hypothyroidism may cause your cholesterol level to decrease, without the need for statins. Statins are also more likely to cause muscle damage in people with an underactive thyroid.

[Josephine63 in reply to SlowDragon]

Again, thank you for such excellent, helpful and fast advice. I did know that T3 was likely to reduce cholesterol and that cholesterol is likely to be higher with hypo, but I did not know that statins were not recommended for hypos ... nor, it would seem, do all gps!!!

Thanks again! You are wonderful!