Has anyone tried less frequent levothyroxine dosing to intentionally allow for fluctuation of T4 levels?

[jkozlow3]

Hi everyone,

I'm hypothyroid and also have low testosterone. Injectable testosterone cypionate has roughly a 1-week half-life, just like levothyroxine. Hear me out for a minute...

Most doctors prescribe & suggest once-weekly testosterone injections. You spend part of the week above the range and part of the week in the range. Some men split the dose into 2 weekly doses approximately every 3.5 days which provides a steadier level but still allows for some fluctuation.

Many of the men on the low-T forums seem to feel worse with more frequent injections however vs. once weekly injections - it seems to be highly unique to each person. Some men take it even further and do small injections daily or every 2 days. This seems to work for a handful of men, but most seem to feel worse with daily injections. One of the theories behind this is that the body has natural fluctuations throughout the day - not a steady hormone level. Daily shots allow for no fluctuation. By the time your injection is absorbed and peaks 12-24 later, you are taking another injection.

So this got me thinking...could there possibly be some benefit to taking levothyroxine 2-3x per week in larger doses to allow for some fluctuation? Maybe we'd feel better? Why would we need to take levothyroxine daily in the first place if it has a 7-day half life? That doesn't logically make a whole lot of sense to me.

[Greybeard]

In thyroid healthy individuals TSH and FT4 levels vary throughout the day, this is well documented. I've not seen any evidence that our levels vary day to day, having said that I've read that some doctors prescribe levothroxine to be taken once a week. In general the idea is to try to replicate hormone levels found in thyroid healthy individuals and as dosing every day is nearer, to what the body normally does, than say once a week, then that is normal practice. If you were to try dosing intermittently it would make interpreting blood tests more difficult, ie where within your intermittent cycle would it be helpful to do a blood test?

[Lalatoot]

In theory you could dose once a week or 2 or 3 times a week.However, you might find that with the larger dose that you would take conversion might be worse and your ft3 level might drop

Why? The body has a safeguard mechanism. When the body thinks that it is at risk of potentially having too high a level of ft3 it converts more t4 into reverse t3 rather than into t3.

There is not a measure for how high ft4 levels need to be for this to happen, it is an individual thing. There is a theory that for some folks the spike in ft4 level from their daily dose is enough to trigger this mechanism of poorer conversion. These folks benefit from taking their levo in multiple daily doses.

So if you took a large dose once every few days the spike of that dose might cause ft4 to spike so high it started converting more to reverse t3 and you'd be worse off hypo wise.

If you want to replicate the normal fluctuations of a thyroid gland then you would dose t4 levo several times a day as the thyroid produces throughout the day as necessary.

[tattybogle]

basically . if you're up for an experiment . you could try it .

once weekly dosing of Levo is used by doctors in certain circumstances . it is considered to be 'safe' . (they probably wouldn't be happy to try it on anyone with a heart problem though)

weekly dosing is not a first choice for dosing levo , but eg if someone is non compliant with daily dosing and medication taking needs to be supervised , then once a week is sometimes prescribed to simplify this . ( it's pretty unusual , but even though is not ideal , it is better for the patient than taking nothing or taking it unreliably )

Also when conducting formal 'Levothyroxine absorption tests"... eg (to differentiate between genuine poor absorption from the gut , and non compliance) then 7 / 10 days total dose of eg 1000mcg is usually given (under close observation to make sure the patient actually takes it) , and the blood levels of fT4 are tested before, and at intervals afterwards.

i haven't ever tried taking a weekly dose , but i would expect to be able to 'feel' that i had rather too much to start with .. and then be feeling extremely groggy towards the end of the week . (I've no intention of trying it because of the negative effect such a large spike in FT4 levels may have on my conversion of T4 to T3 ... and because i can feel a subtle difference by about 2 pm if i forget to take a morning dose) .

So if you did try it , do it with caution ,as it could be pretty unpleasant at first, and it could really mess up your week at work ... or it might not.... there's only one way to find out ., but whatever happens , you're stuck with it for the week.

i split my daily dose into 2 and take half before breakfast and half before bed, to more closely mimic the rise in fT4 overnight / am that body naturally gives itself .

Some people naturally have a large daily fluctuation.... in others it is much flatter.

these are graphs of two(healthy unmedicated) people with the largest /smallest daily rhythms taken from a study.

(Thanks to Tania S Smith ThyroidPatients.Canada for the image)

.

[arTistapple in reply to tattybogle]

Thanks Tattybogle. Similar question re: T3. I have had problems trying T3. Heart stuff now being investigated (again). However I have come to notice, even although it was pretty terrible trying T3, that it has left some good things behind. Similar when I over dosed on T4. Anyway the T3 question. Why does T3 have to be taken regularly. Could it be taken less often with a view to getting a little boost now and again. I know you don’t take T3 but your T4 explanations are excellent.

[tattybogle in reply to arTistapple]

not so confident with explanations re.T3 as never taken it so have no practical experience to measure the theory against.

But my instinct says variable dosing for T3 is probably not such a great idea .

The body's main aim seems to be to keep its T3 levels as stable as possible, despite all sort of other influences going off .. eg. when thyroid is failing and T4 is getting low .. it changes thyroid's production ratio of T4:T3 , and tweaks the deiodinases , to protect it's T3 level for as long as possible. till it can't anymore

When FT4 is too high , it tweaks the deiodinases in the opposite direction to keep T3 as stable as possible ,

The only time it seems to 'deliberately' allow T3 to go lower is when you are critically ill, when presumably it thinks it's abetter idea for you to stay lying down rather than running around .

and the only time it allows it go higher is when it really cant stop it from doing so because your thyroid went totally nuts.

So my assumption is the body is quite fussy about keeping T3 levels as stable as possible (barring the regular effect of the circadian rhythm) and i trust the body to know best when left to it's own devices , so i reckon we should copy it as far as possible .

[arTistapple in reply to tattybogle]

Thanks again Tattybogle. Just going through a phase of T3 envy. It seems like it’s the answer but NO! Trying to read the stuff from thyroid.ca but less than o’grade science is just not cutting it.