Would like to ask about ratios between T4and T3 - Thyroid UK

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Would like to ask about ratios between T4and T3

Pastelart profile image
10 Replies

A friend has some thyroid issues and I’d like some advice on her behalf.

Thyroid was removed 38 years ago

Was on 150mcg levothyroxine till the GP insisted on reducing to 125 mcg because of osteoporosis

Her heart rate is very slow, 45 on waking and daily average is 50/55

I advised private test, results below

TSH 0.72 (.27-4.2)

T4 22.5 (12-22)

T3 3.9 (3.1-6.8)

I can see that her T3 is very low

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Pastelart profile image
Pastelart
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SeasideSusie profile image
SeasideSusieRemembering

Pastelart

Did she do the test according to our advice, ie no later than 9am with water only to drink (no food or other drink), no biotin/B Complex for a few days before test and - most important - last dose of Levo 24 hours before test?

Are her key nutrients at optimal levels:

Vit D - 100-150nmol/L

B12 - top of range for serum B12, if Active B12 then 100 plus

Folate - at least half way through range

Ferritin - half way through range although some experts say that the optimal level for thyroid function is 90-110ug/L.

If so then her results show poor conversion and she may benefit from adding some T3 to a lower dose of Levo.

If key nutrients aren't optimal then these should be addressed before considering the addition of T3, optimal nutrient levels should help conversion - particularly ferritin.

Pastelart profile image
Pastelart in reply toSeasideSusie

Thank you SeasideSusie, I will check with her as above, but I know that she fasted prior to test and did it before 9am

jimh111 profile image
jimh111

Her fT3 is not very low, it is well within the reference interval which shows the limits 95% of the healthy population fall within. T3 / T4 ratios are a misleading concept as the body tries to maintain stable T3 levels ncbi.nlm.nih.gov/pmc/articl... . So, if fT4 is high the fT3 / fT4 ratio will be lower than when fT4 is lower. We each have set points for our TSH, fT3 and fT4 levels.

The doctor is right to lower her levothyroxine because of osteoporosis as some studies link fT4 to osteoporosis. I would see how she does on the lower dose, if it makes her more hypo. it would make sense to request some liothyronine. It would be useful to know what the thyroid issues are and how severe. Her pulse is low, this could be because she is fit or there could be a problem.

Poor conversion can occur due to selenium deficiency but this is unlikely to be the case as her TSH is not high. If she had a nutritional deficiency causing poor conversion her TSH would be very high as the pituitary would be unable to convert T4 to T3 and so couldn't respond to T4.

pennyannie profile image
pennyannie in reply tojimh111

The lady had a thyroidectomy some 38 years ago:

jimh111 profile image
jimh111 in reply topennyannie

Her fT3 will be a little lower as without a thyroid she will no longer secrete T3 and she will miss the T4 to T3 conversion that takes place within a thyroid. I think she should be on the lower levothyroxine dose and given some liothyronine to bring her fT3 up around mid-interval. There's lots of evidence that people with little or no thyroid function should receive T3. Also high normal fT4 levels are associated with cancer and cardiac problems.

Pastelart profile image
Pastelart in reply tojimh111

Thank you jimh111, I will pass this on.

pennyannie profile image
pennyannie

Hello Pastelart :

The accepted conversion ratio when on T4 only medication is said to be 1 / 3.50 - 4.50 with most people feeling at their best when they come in at around 4 or under.

So to find the conversion ratio you simply divide the T4 by the T3 and I'm getting your friends conversion ratio coming in at around 5.7 so very wide and out of centre.

Her conversion may well be a little ' better ' at a lower T4 reading but considering she has lost her thyroid, and lost her own T3 / T4 thyroid production I believe the logical solution is to at least replace both these vital hormones and restore T3/T4 hormone balance to around a 1/4 ratio T3/T4.

A fully functioning working thyroid would be supporting her on a daily basis with trace elements of T1, T2 and calcitonin + measure of T3 at around 10 mcg + a measure of T4 at around 100 mcg.

T4 is a storage hormone and needs to convert within the body into T3 which is the active hormone that runs the body which is said to be around 4 x more powerful than T4 with the average person needing to convert and utilise around 50 T3 daily just to function.

No thyroid hormone replacement works well until core strength vitamins and minerals are optimal especially those of ferritin, folate, B12 and vitamin D and conversion can also be compromised by inflammation, any physiological stress ( emotional or physical ) dieting, depression and ageing, so, whilst we can't turn back the clock we can try and do something about most of these other stumbling blocks.

Pastelart profile image
Pastelart in reply topennyannie

Thank you so much pennyannie, that makes sense to me.

pennyannie profile image
pennyannie in reply toPastelart

The reality is by not replacing both T3 and T4 after the medical intervention of either a thyroidectomy or RAI ablation for Graves the patient has been down regulated by around 20% of their over all well being and over time, this is bound to have consequences.

Some people can get by on T4 only :

Some people find T4 seems to stop working as well as it once did and find adding back in that little bit of T3 lost restores their health.

Some can't tolerate T4 and need to take T3 - Liothyronine only .

Whilst others find their health restored better by taking Natural Desiccated Thyroid which contains all the same known hormones as that of human thyroid gland and derived from pig thyroids dried and ground down into tablets and referred to as grains.

All these treatment options were available through your NHS doctor but around 20 odd years ago the rules started to change, and now to obtain anything other than T4 you will need a referral to an endocrinologist who may or may not prescribe - due not to medical needs but cost constraints, as it has become a post code lottery.

Pastelart profile image
Pastelart in reply topennyannie

Thank you, what a minefield this thyroid stuff is 😩🤗

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