Anyone take T3 Sublingually? : I am on the Uni... - Thyroid UK

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Anyone take T3 Sublingually?

Rhsana profile image

I am on the Uni-Pharma Liothyronine Sodium, I was recently told that you could take this sublingually and would have a better chance of getting to the cells as I have a pretty sever case of Dysbiosis in the gut. Does anyone else have any experence wth that?

R xx

52 Replies

I've never found it makes any difference, but it might depend on the excipients in your particular brand and how you react to them. On waking, I just crunch the tablets to a powder and wash down with water.

Rhsana profile image
Rhsana in reply to Hillwoman

Thanks Hillwoman, just out of curiosity why do you crush it up first?

R x

Hillwoman profile image
Hillwoman in reply to Rhsana

I just reasoned that if it reaches the stomach ready-chewed, it will be digested quicker.

SeasideSusie profile image

From what I have read, the molecules are too big for T3 to be taken sublingually, and it should be swallowed with water. I don't know how Dysbiosis would affect it though.

T3 molecules are too large to be absorbed by the under-tongue method. The tablet just dissolves in your mouth, some of it gets swallowed, some hangs around your teeth and possibly binds to whatever you eat next. It is a very unreliable way of dosing your T3.

All thyroid 'meds' are designed to dissolve in stomach acid, in an empty stomach.

Rhsana profile image
Rhsana in reply to greygoose

Thanks for clarifying greygoose and SeasideSusie! The dysbiosis and low thyroid effect my stomach acid levels (very low) this was one of the reasons why I was looking into the sublingual method but I had no idea the molecules were too large, hence making that a massive waste of time! Thanks again! R x

greygoose profile image
greygoose in reply to Rhsana

You're welcome. But, you know, most hypos have low stomach acid. There are things you can do to raise it, and increase absorption. Why not post another question asking about that, it's not my area of 'expertise'! lol

Rhsana profile image
Rhsana in reply to greygoose

Hey greygoose , yep, I'm using ACV and trying to aid it with diet (not a diet), Unfortunately it just takes time to readjust the balance down there. R xx

greygoose profile image
greygoose in reply to Rhsana

Yes, it all takes time. :)

heathermr profile image
heathermr in reply to greygoose

No sorry that's NOT true. When swallowed, the action of swallowing starts up the production of stomach acid which destroys some of the action of the T3, where as in the mouth its slides readily across the cell membranes and into the blood stream for transport to all areas of the body. In no way are the molecules too big otherwise they would never get around the body! Try dissolving a tablet of T3 in your mouth, its gone in about 30 seconds and does not hang around your teeth or anything like that. It goes to work PDQ in your blood stream! I can feel the difference after dissolving T3 in my mouth within minutes, its like turning on the central heating in the house and getting a big dose of "get up and go"!!

Stomach acid is designed to break up anything that passes down the gullet. In the same way it breaks down the T3 and blocks some of it working. T3 medication does not need to be "broken down", it needs to get into the blood stream as it is to work.

Try asking any Bio-chemist who works with the human body.


greygoose profile image
greygoose in reply to heathermr

Well, I'm afraid your opinion is in the minority. Even the manufacturers say that it should not be taken sublingually, it needs stomach acid to separate the T3 molecule from the sodium molecule it is bound to, to make it into a tablet. Perhaps you would like to take it up with them?

heathermr profile image
heathermr in reply to greygoose

Sorry again but that's not the whole story either. My husband spent his life as a Biochemist working in the Pharmaceuticals industry both here and abroad and with several universities. He says that when dissolved in the mouth T3 looses its sodium molecule naturally when it reaches the blood stream as ions (like sodium) are carried independently in the blood. So the T3 is ready to go straight to work. In the stomach, the stomach acid goes to work dissolving not just the sodium off the T3 but a large part of the T3 itself and only part of it makes it to the intestines where it is absorbed.

Having tried both methods of taking T3, I note that swallowing the tablet makes its absorption very much slower and that it does not work as well. I would probably guess that it feels like I am loosing about 40% of the dose I have taken. Absorbing it under the tongue means it goes to work very quickly- like turning on the heating system and giving me a dose of get up and go, and lasts for a good number of hours. I have used this method for well over 6 years and have had no problems.

The manufacturers are very much under the hand of Doctors and I am sure most of them are still under the illusion that T3 causes A Fib (which we all know that it doesn't) and this is why they have put pressure on the manufacturers to recommend swallowing the tablet even though it doesn't work as well. This is quite common in the Pharmaceutical industry as Doctors have the final say over everything.

I suggest you try the sublingual method, you may just be surprised!


greygoose profile image
greygoose in reply to heathermr

I have tried the sublingual method. I wasn't surprised.

Given that doctors can't even manage to get labs to do all the tests they want, l cannot see how doctors could possibly have the last word with Big Pharma.

RedApple profile image
RedAppleAdministrator in reply to greygoose

Judging by personal experience and what we see recounted here, most doctors don't even know what T3 is, or what it does, so aren't in a position to tell us how we should or should not take it. I've always been under the impression that it's more likely to be Pharma that controls what docs prescribe, not the other way around.

evdebs profile image
evdebs in reply to RedApple

I agree and i've been surprised how unfamiliar most docs are with thyroid issues or meds.

RockyPath profile image
RockyPath in reply to heathermr

Thank you, heathermr, for sharing your knowledge. Perhaps there are variations within humanity as to how the hormone is absorbed. I tried what you suggested and I WAS surprised.

Taking 2.5 to 5 mcg into my stomach, either empty stomach or with a meal, I found it was taking 5 to 5-1/2 hours to notice any effect. This is a LONG time when you feel unable to move or think clearly. I took perhaps 0.3 to 0.6 mcg under the tongue, savoring it as long as possible without swallowing the saliva. I felt the change in my brain function and muscle energy within 45 minutes, and felt like my old self within 90 minutes. Amazing! I'm so glad you persisted and shared this, and that I could find it via search engine!

in reply to RockyPath

This sounds really reasonable to me. My gut feeling tells me my T3 is probably passing thru my gastrointestinal system so fast it does not even have time to collect it's $200.00 lol. I am so physically tired I just took a 5 mcg T3 pill sublingually to see if I feel a difference.

It's 3:20 PM here in Georgia (US) and I'm curious to see what happens. I took my normal dose this morning at 5AM.

I am also considering taking my meds at bedtime.

Was going to wait til my next lab appt. but #$@% that. If I can feel better now I'm willing to try sublingual. All it can do is not work!

Thanks for your input. irina

_HMP profile image
_HMP in reply to heathermr

When taking sublingually, do you still have to take 2h after and 30m before food?

heathermr profile image
heathermr in reply to _HMP

No I usually wait about 10 minutes before and after my T3 to eat food and drink. This makes it easier to manage when out and about and taking multiple small doses of T3 throughout the day. I've now been on T3 taking it subliminally for about 16 years and remain convinced that this is the best way ( and most convenient) to take T3. I've persuaded my Endo to give me Cytomel rather than British T3 because not only is it cheaper for the NHS to buy but it also works much better. Hope this helps.


helvella profile image
helvellaAdministrator in reply to heathermr

I really don't understand the basis for what you are saying.

Firstly, you say that stomach acid breaks down T3.

Hopefully we agree that stomach acid is mainly hydrochloric acid.

But the formal identification of liothyronine involves dissolving the sample (of what you think might be liothyronine) in ethanol and hydrochloric acid then checking the absorption spectrum. If the hydrochloric acid were busy breaking down the liothyronine, would this be a sensible identification method?

Of course, my gross simplification might be missing something such as differences when ethanol is present. On the other hand, hydrochloric acid is used in some other identification methods without ethanol.

Hashihell profile image
Hashihell in reply to heathermr

Heather, thank you so much for your response in this forum. I absolutely agree. Swallowing T3 whole for me did nothing. I had to take super high doses to feel any benefits and in the meantime became extremely Hypo. I finally let it dissolve on my tongue, after 5 months of taking orally with no signs of improvement with my hypo symptoms, and it is a totally different experience. I essentially have to start all over again though with determining the proper dose for me. So swallowing it for the past 5 months was a waste of my time and health and money. Just my opinion on this matter.

Anyone have any further info on the T3 molecules being too large to absorb?

Marz profile image
Marz in reply to Rhsana

Check out

Rhsana profile image
Rhsana in reply to Marz

Wow!!! Thank you!

in reply to Marz

Just found this thread today. Thanks for the heads up. I believe I am having problems absorbing the T3. Just ordered the "Recovering with T3" from amazon. Here (US) the 2018 edition is $29.00. irina

RockyPath profile image
RockyPath in reply to

Hi, it's unlikely you are not absorbing T3. More likely you are producing too much rT3; perhaps from taking Levothyroxine. From my personal experience, if the T3 doesn't seem to be having any effect it is because there is not enough of it. My endocrinologist advised me "Do not take any more thyroid hormone" so when I determined that the combination of levothyroxine and T3 wasn't meeting my needs, I eliminated 50 mcg of levothyroxine from my daily intake and replaced it with 12.5 mc of T3. I swallowed it and it did the same thing as taking it under the tongue. The endocrinologist thought I might explode if I took it sublingually so I thought I'd prove to him it wasn't as scary and dangerous as he had been led to believe.

There are people on this board who do not have experience with rT3 and hence view it as some magical figment of our imagination and something that is perfectly harmless, which it is not. I know from bodily, empirical evidence, and this is supported quite thoroughly by the research articles that have been published since the 1970s I offer some links to a few of the many articles, which if need be may be shared with your doctor.

in reply to RockyPath

Thanks Rocky. Very helpful info. I am going to suggest cutting my levo next visit.

I also experimented yesterday afternoon after writing my posts. I took my PM T3 dose sublingually. And I felt the difference. It took about 20 minutes to dissolve as I didn't want to dilute with water and accidently swallow the pill.

Usually I'm dragging by about 3PM and have to perk up with a cup of coffee. But after the sublingual approach I felt fine, energized thru the evening and didn't need coffee.

You have a point about absorption and the rT3. What makes me lean toward the absorption problem is in 1999 I had uterine cancer and received quite a lot of radiation to my abdomen.

Everything turned out fine and I didn't give it another thought for years. Aside from some minor discomfort if I ate the wrong foods I didn't think I had any residual effects from the radiation.

But in 2017 I had my gallbladder removed and my surgeon told me I had quite a lot of damage from the high doses of radiation I received. This made other things I had noticed through the years make sense as I now feel all along they were caused by the radiation.

I'm due for endo labs soon and will ask for an rT3 test tho I have a feeling it will be absorption. At least I now have an endo who works with me and listens to my input (most of which I get from this forum.) 😊

Take care. irina

heathermr profile image
heathermr in reply to Rhsana

I dont know who has said that the T3 molecules are too big for absorption sublingually because this is NOT true! It is in fact the best way to take them as they are readily absorbed in the mouth and pass directly into the blood stream and hence to all areas of the body. Taking the medication via the stomach means that it becomes mixed with the stomach acid which is ever present in the stomach which does block some of its action.

My husband is a Bio-chemist who has worked with the human body for all of his working life and in Universities and the Pharmaceutical industry both here and abroad. He says that the cells in the stomach are the same size as those in the mouth and in no way are the molecules of T3 too large to be absorbed into the blood stream where they are needed.

I have taken T3 sublingually now for over 6 years and it works very well for me. I have recovered from almost being in a coma because of hypothyroidism to being active physically although the lack of the right medication for my hypothyroidism has meant that I now have hypothyroidal dementia. T3 medication is helping that a great deal.


I guess, I don't understand how with NDT the molecules aren't too big to be taken sublingually and with T3 they 'are'... I don't know anything about this but I also can't find enough information for either side of the argument. Does anyone have any links to where they can confirm what they mean by the molecules being too large? aside from this one; regards to what the manufactures say.... I've know them to be wrong/misleading before so I don't have a huge amount of trust in that, but greygoose, am I wrong in thinking you did at first take your T3 sublingually, so by your own experience you found it not to work as well?

greygoose profile image
greygoose in reply to Rhsana

You are correct, Rhsana. I did use to take it sublingually, and it wasn't as good as swallowing it. I was advised to do it that way on another forum, so I gave it a try.

But, who said that NDT could be taken sublingually? It's just the same, the molecules are to large to pass through the cell walls under the tongue. And, they may very well be the same size cells as in the stomach, but it isn't supposed to be absorbed in the stomach, either. It's absorbed in the gut. All thyroid hormone replacement is designed to be swallowed. There are no sublingual hormone pills, like there are B12 pills.

And, I agree that manufacturers can be wrong - such as when they say to take levo half an hour before food, when we know that waiting an hour is better. But, I think I trust them on this one.

Have you read this?

Rhsana profile image
Rhsana in reply to greygoose

Yes, I believe it is the same link I posted above. It is the only place where I can find the claim about the molecules being too big and it must be said, not an entirely well researched article (perhaps because the research just does not exist at the moment?);

"Thyroid medication was not designed for sublingual use, therefore the size of the thyroid hormone molecule means that sublingual use of thyroid medication may not be optimal for some patients as far as absorption, and may not prevent interactions that can reduce absorption of thyroid medications."

I notice they use the term 'may' which to me denotes that they do not actually know this to be a fact. They then go on to say 'there haven't actually been any studies done on this but we think it may be because of...';

"Since there have not been any studies to evaluate the effectiveness of the sublingual route for natural thyroid, we can only speculate that perhaps these patients may have some sort of digestive malfunction, i.e. rapid digestion, which means that the pill may not even be fully dissolved before it leaves the stomach and goes into the intestines, or the insufficient enzymes to dissolve and digest the pill. By crushing/dissolving the pill in the mouth, perhaps this is allowing the pill to break down and begin to be digested."

I guess what I am getting at, is I have heard a lot of claims regarding the size of the molecules and it not being effective (but haven't seen any real evidence to support those claims) to the contrary of a section of thyroid patients who claim it is the best way for them to take their medication. And while they have no 'proof; to back their claims up either, they do say they feel better for it. And aren't we as a community often left feeling very disappointed because there isn't enough importance put on how we feel among the medical community?

greygoose profile image
greygoose in reply to Rhsana

Well, that's true. So many areas of thyroid remain unresearched. And, frankly, nobody cares. There's just no money in it for anybody. We, the patients, do what we can, but it remains anacdotal.

in reply to greygoose

Hi gg: I agree about the molecules and read the article on

But I am so tired and desperate I am going to give the sublingual a try. Like chicken soup it can't hurt.

I have so many G.I. absorption issues and as is the way with many things in medicine there are always those of us who do well even when the literature says we won't.

Here's hoping... Rereading some threads I was reminded that you are doing well on T3 alone. This is going to be my next battle. I was out of my T4 for several days and couldn't get to the pharmacy. A rare occurrence for me to miss meds but I noticed that for those days I didn't have my usual morning abdominal pain after taking my thyroid meds.

Since my thyroid is atrophied from radiation and my sense that I'm a poor converter it's logical to me to let go of the T4 and try T3 alone.

I plan to hit the doctor up with this on my next visit.

The daily morning G. I. symptoms are not fun.

greygoose profile image
greygoose in reply to

Are you saying you're going to try T3 sublingually, or levo?

Can't do any harm? Who knows? But very often we see on here that people who take their T3 sublingually have low levels of FT3 compared to their dose - so you might need a higher dose doing it that way.

As for letting go of T4... Maybe, maybe not. Is T4 just a storage hormone? Or does it have its own job to do? There is no definitive answer to that. As with all things thyroid, we just have to try it and see - or, in this case, suck it and see! lol

in reply to greygoose

I want to try the T3 sublingually. You're right. Lots of unanswered questions. And valid points on both sides of the coin.

I will talk to the doc before letting go of T4 as I do believe everything the body makes has a purpose even if we don't know 100% what it is.

But I'm willing to try some experimenting as I am following my new (April) endo's treatment exactly and at first felt better but am now VERY tired and I don't see other reasons why except my thyroid.

In the last month I've seen practically every doctor I have and no problems have cropped up with other body systems.

Also I have a big consult the beginning of February with a well-known orthopedic doctor at Emory University re my knees.

In a word, they are very bad- painful and out of alignment- and my regular ortho wants to see what this guy has to say so made a referral.

Meanwhile I just want to have everything working as well as possible. I really don't want knee surgery but I see the writing on the wall! 😡

greygoose profile image
greygoose in reply to

Perhaps you just need an increase in dose? Or, before you try sublingual T3, why not try taking vit C with your thyroid hormone, to see if it increases absorption?

For you knees, have you see a chiropractor? If they're out of alignment, I would have thought that was the person to see.

in reply to greygoose

I do take Vit C,Magnesium, D3, K2-MK7, Vit E and eat weekly liver for Ferritin, B12, and a good B complex. Have been faithful about my supplements since learning what I should have tested here.

Re Chiropractor I'm on the lookout for one as more info is arising re how they often help atrial fibrillation.

But probably my terms were wrong. My thigh bone no longer sits exactly on top of my lower leg bones at the knee joint and the x-rays look like they might slide off. Very weird.

But I'm willing to ask him about a chiropractor or even braces to keep from having the surgery. Feb 6th is the big day.

My sister who is a medical transcriptionist and is up to date on medical care says "Don't worry. Knee operations are fairly easy these days." But too many years in the operating room has taught me surgery is never easy and doesn't always turn out well.

I'm not afraid of the surgery. What scares me is ending up with permanent mobility problems that might mean a higher level of care (assisted/nursing homes.)

This way of life and losing independence is NOT quality of life for me.

Thanks for letting me go on. I am really nervous about this.

greygoose profile image
greygoose in reply to

No, I meant take vit C at the same time as the thyroid hormone - as you would take it with iron to increase absorption.

I did understand what you mean by 'alignment'. That's what a chiropractor does, realigns the body. My knees and hips were out, and a chiropractor got them back into place again. I haven't had any problems with my hips, since (touch wood!). Although there has been the odd blip with my right knee, since then. :)

in reply to greygoose

I don't take the Vit C with the thyroid. In fact I don't take any meds within 4 hours of my am thyroid meds. I get up at 5am, take them, and go back to bed. I want to give the thyroid meds every chance to be absorbed as well as possible. 😊

greygoose profile image
greygoose in reply to

Yes, I understand, but vit C is different. You can take it with thyroid hormone, and it does improve absorption.

in reply to greygoose

Thanks. I got it @$%backwards. Then that's what I'll start doing. 🐱

helvella profile image

Putting all other issues to one side, I am concerned that sub-lingual could be bad for your mouth. Your mouth, anywhere near the tablet, will be getting a huge dose of T3 (assuming any does actually get absorbed!) Just possibly this is not good for the cells themselves?

At least swallowing with some water can achieve a wider distribution.

greygoose profile image
greygoose in reply to helvella

That's a good point. What's more, l do wonder if taking it sublingually, didn't hastenthe demise of my front, lower teeth!

Just as another input- doesn’t prove anything of course- but I’ve been taking t3 sublingually for a few years now and I never go to the dentist and everytime I do finally go they are amazed I have no cavities or plaque since I don’t get frequent cleanings. Also I only brush with water, no toothpaste. I don’t eat any sugar. I think that’s why my teeth are fine, but seems like if t3 sublingual were harming teeth something would have happened in that regard to me by now.

Mountainfever - this is a year old post and may not be seen by the OP.

Well, I certainly didn't see it! lol

You're right, Mountainfever, that doesn't prove anything - nor do I know that taking T3 sublingually ruined my teeth. But, just like everything else, all teeth are not made equal! You need good nutrition from conception to have good teeth. I didn't, as I was born just at the end of the last war. Food was rationed and short, and that's had a lot of effect on my teeth, plus the hypo - because you also need good hormones to have good teeth. And, I've been hypo since I was pretty young. So, my teeth just didn't stand a chance, really. Something would have got to them, one way or another. If it hadn't been the sublingual T3, it would have been something else. That was just a throwaway remark, not an attempt to prove anything. Not really worth reacting to. :)

in reply to greygoose

I think sometimes we have certain problems difficult to deal with and so the Universe gives us a pass on other things.

My teeth are all mine with few problems. Have not used toothpaste for years-just baking soda, gargle with salt and practice the Indian custom of "oil pulling" most of the time.

On the other hand my sister has full dentures. She is younger than me and has had them for years.

Do you think it could be because she keeps Malteasers by her bed to eat at night??? LOL 😂

greygoose profile image
greygoose in reply to

Well, I've had problems with my teeth all my life - even with my milk teeth. And at the time I had milk teeth, I didn't have any sugar in my diet! Sugar was like gold dust in the UK at that time. It was rationed and so were things like chocolate. So, it wasn't sugar my undoing in those early days.

in reply to greygoose

Rationing sounds like a very reasonable reason. My teeth are not pearly white like my sister's and I used to be envious but I heard somewhere that people with very white teeth are more prone to problems that those of us that don't have them. Something about very white teeth being softer. Who knows.

Teeth are a big thing over here.People are frequently judged on their smile and looks in general. The big thing here now are dental implants. They look perfect.

I personally wouldn't put myself thru that but I do confess to using whitening trays every so often.

There is a lot of pressure here to look as perfect as you can.

I'm past that. I just want to be healthy. I think I look okay but my sister is very much into antiaging creams, makeup, etc.

greygoose profile image
greygoose in reply to

Oh, I'm with you on that one! Never have been one for dollying myself up. Rarely ever worn makeup. As long as I'm clean, I'm ok, I prefer to look natural. :D And that smiley has more teeth than me! lol Perfect I'm not! But, I've done OK as I am.

Rhsana profile image
Rhsana in reply to helvella

I don't know enough about how T3 works, clearly! So by that thnkng is the same true when taking other sublingual medicines? The mouth would have to endure a huge dose of whatever medicine being taken (not sure I can name any other than b12, Apologies for my lack of knowledge here still very knew to all of this!)

helvella profile image
helvellaAdministrator in reply to Rhsana

I fully agree with you that there would be a relatively huge dose. But the extremely small quantity of T3 (most medicines are measured in milligrams, rather than micrograms), makes the issue potentially even more dramatic.

Obviously, the mouth must be able to cope with quite a lot but this sublingual taking of extremely potent medicines has always conerned me. Most of the time I just shut up because I am no expert.

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