Ft4 ft3 ratios ???

[Ruth63]

What does ft4 ft3 Ratio mean ? And how would I go about working mine out ? Is it important?

[jimh111]

This question was asked two days ago so you might like to look at the replies healthunlocked.com/thyroidu... .

[Phoenix605]

Hi Ruth, working out the ratio is simple, divide FT4 by FT3. a good ratio is generally considered around the 4:1 mark. When we take T4 the body converts it to T3 for the body to use. The ratio simply gives a rough indication of how well this process is being performed.

As hypos we are commonly low or deficient in key nutrients the body requires which can affect conversion rates. I was low in B12 and folate and deficient in vit D. At the time I had a ratio of around 3.5:1 with reasonably good thyroid levels but still niggling symptoms. fixing those nutrient levels brought my ratio to 4:1. I felt better for two reasons, firstly I was getting more of the active form of the hormone available to my cells so I was better medicated without a dose raise. Secondly, fixing those nutrients showed they were deficieny symptoms rather than thyroid symptoms. many symptoms of nutrient deficiency mimic hypo symptoms so it is no use increasing levo without getting all your other ducks in a row too. This conversion can also be affected genetically but I believe there is usually a very marked discrepancy when that is the case.

The ratio is only helpful if you take levo, NDT contains mostly T3 soFT4 tends to be lower. T3 only is obviously going to have a similar effect. Regular hard exercise also skews the results as the body speeds up conversion to offset the high demand for T3 resulting in an FT 4 drop.

[Ruth63 in reply to Phoenix605]

Thank You, this makes more sense to me x

[Ruth63 in reply to Ruth63]

Mine ratio looks like it's 3.2, would this make a difference with the Drs? X

[Phoenix605 in reply to Ruth63]

Realistically no not unless you have a very good one! They only get half a day on thyroid so have no idea about ratios, nutrients, good testing protocol etc.

If you have symptoms and have not already had them tested, I would certainly recommend getting b12, folate, ferritin and vit d tested, they could be what is causing symptoms or a slight FT3 improvement could be enough, both were true in my case. Also if your levels are good it would rule out nutrients as the cause of residual symptoms or fixing levels may show that you are correctly medicated with levo.

If GP wont play ball with these tests you can get them done privately through Medichecks or Blue Horizons, they both often have offers on and if you go via TUK they get a small donation to help with running costs. Unfortunately, their docs tend to follow the same ‘in range’ syndrome as GPs so post results here in a new thread for advice or search SeasideSusie and read her answers, she gives very good advice.

At the end of the day dont get too hung up on the numbers as we are all different what matters is how we feel. however, it is worth noting them when you feel well so you know what ballpark your optimal results are in and have something to aim for if things slip.

[Ruth63 in reply to Phoenix605]

Thank you I will try what you suggest x