Thyroid UK
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Depression and anxiety

I have been on T3-only for 18 months.Most of my troubling hypothyroid symptoms on T4 monotherapy have dramatically reduced.

My latest blood results show my FT3 is at the top of the range.

So why have I been experiencing anxiety & depression since September?My enthusiasm for life has dramatically reduced.My motivation levels have plummeted.I have insomnia & a big reduction in appetite & enjoyment of food.

When I have tried adding some T4 in,tachycardia & ectopic beats return.But is it possible I need some T4 to stay mentally well?

I have also lost a lot more hair since on T3 only

13 Replies

A very common issue with thyroid is starting to feel unwell come September (it always starts for me in that month). Last year i worked out the cause for me. Vitamin D !

I need more Vit D in the winter months and so now supplement. It has made a big difference. I have tried stopping and after a day or two i feel more tired etc. So i stsrt again and all is good.

Cant say for sure this is your reason for not feeling so good, but worth getting Vit D tested and start supplementation. I think 50 nmol/l in the UK is seen as good, but really you want to be nearer 100 or higher.

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Many thanks for your reply.

I was wondering if a SAD lamp would help.I have been taking 2,000 D3 with K for quite a while,but am now taking 5,000 for 3 months.Also taking 5,000 B12 methylcobalamin.

I get as much walking outdoors as I have strength for,always at least 30 mins a day,usually an hour


Ok, so you are doing the Vit D, so probably not an issue for you.

Sad lamps are supposed to be good. could be worth a try.

What T3 dose do you take and what was the FT3 ?

Could you need an increase in the winter months. Dr Blanchard in his thyroid book says many patients need to raise thyroid meds in the winter and lower in the summer.

Dr Myhill mentions Dr Blanchard in her section on thyroid problems. I got his book and it is great. He believes patients do best on T4 and a tiny bit of T3. so a 98:2 ratio. Probably not the best read for a T3 only user however.


I am open-minded about T4.I would prefer to be on NDT,but the supraventricular tachy & ectopics have been an issue when I've tried it.However,this depression & anxiety are far worse!Thinking of trying a purer NDT than Thiroid.Willing to try anything


What T3 dose do you take ?

Have you used small doses of T4 ?

When T3 only didn't do it for me i switched to a low T4 dose and kept the T3 at 55. So i was on 25 T4 and 55 T3. Worked really well, bit i wanted to see if i could use more T4 and less T3 after a yr. So over the next yr i switched to 125 T4 and 25 T3. Prior to all this is used 150 T4 and 50 T3, but was unwell still.

My thoughts were the receptor cells were retrained to suck up the T3 because i gave the body less T4 to interfere with RT3 creation and cell blocking. The higher T3 level was able to go about its business and get into the cells. The small T4 amount sat there not getting in the way, but augmented my health.


Am very interested in your experiments with T4 & T3.When I added NDT to T3,something went wrong on a cellular level,(RT3 I think,tying in to your experience)I have been on 55mcs T3 for over a year.I dropped it to 50mcgs recently,when November blood tests showed my FT3 at 6.4(range3.80-6.00)

I was wondering if I should try 50mcs T3, 25mcgs T4 to avoid RT3 problems?How did you adjust your doses when increasing T4,reducing T3 over the year?I only went on T3 to help adrenal insufficiency.I feel that worked,but now I think I need T4(hair loss,tinnitus,anxiety/depression) but don't want a repeat of my 2 trials of NDT with T3.


I had been wondering how long it would take for a VitD tablet to kick in. I've only been taking one when I remember, but do get definite down days.


Another thing to consider is over medication. I used T3 only years ago and couldn't go past 55 T3 as any more made me hypo. Not sure if this may be your issue, but a very simple way to work out over medication is to drop down a dose level. With T3 you should notice changes very quickly.

Very often people are over medicated on thyroid meds and they don't know it. They are addressing loads of the other metabolic issues and don't realise they are improving T3 uptake and overall metabolic function. For example, better Vit D levels or other mineral levels can enhance T3 conversion and absorption so the person now requires a bit less thyroid meds.

Over medication is easy to spot if you start getting hot or heart beats faster, but this isn't always the case. For me it meant a shutting down of the system and i felt more hypo. I imagine the RT3 mechanism works well in these instances.

So if you have been addressing other issues around the thyroid area do you think the body is getting better and so requires less T3 ? Could be a possibility, and pretty easy to find out.

I see decreases in thyroid meds as a useful way of testing the body is on the right dose. If you feel MORE ill this is actually good news because you sort of confirm you do need that level of meds.


That is really interesting that you went hypo when your dose was too high.Is that what happened to me when I was taking to much T3,when I added NDT?But it wouldn't have been RT3 in your shutdown,would it,as RT3 only happens when T4 is present?

Sorry I didn't get back to you before.With this depression & anxiety overwhelm,it takes me a few days to be able to absorb the info.

I think my next step is to add some T4 back in,but using thyroxine.I think I will follow your experiment & add 25mcgs T4 to my dose of 50mcgs T3 for starters.If you felt really well on 55mcs T3,with a small amount of T4,why didn't you stick with that?


Too much t3 made me very ill. Never got hyper, just hypo. So my body was doing what it is supposed to do and block the action of T3 if it cannot handle the energy through put. I assume this is RT3 at work, but if anyone else has an explanation i am happy to listen. I think on T3 only we do still have T4 in the system, plus i wasn't on T3 for that long as i remember. Maybe 6 weeks.

Taking T3 is a pain. You have to multi dose and really watch the times. After a year i just wanted to see if i could use more T4 and less T3. I slowly switched over and it took a year to do. I went up in 25 amounts, so 25, 50, 75, 100, 125.

I came down as i felt comfortable. So i remember being on 50 T4 and 50 T4 (so only dropped 5mcg on that increase). At 75 T4 i think i might have been on 40 T3. I cannot fully remember the ratios, but the main point is the decrease is not some system i devised. If you are doing it for yourself, you need to adjust the dose based on how you feel.

I got up to 125 T4 and was on 25 T3 i think THEN i ran into trouble again. It was very confusing at the time, but i realised after a few weeks that my body didn't want the T3 anymore. So i think i switched to 1/4 tablet per day. Then later on i was not using any T3 at all for over a year. Just stayed at 125 T4.

I now use a tiny bit of T3 = 1/8 tablet per day = approx 3mcg. Sounds crazy, but this small amount added to my T4 helps a lot. Dr blanchard in the USA says his patients do best on mostly T4 and a tiny bit of T3. It is a 98:2 ratio approx. Dr Myhill has some good info about his working on her website.

I bought his book and think it is one of the best on thyroid and it sort of goes against the commonly accepted new doctrine that T3 needs to be used in a 3:1 or 4:1 ratio. Yes lots of people seem to want this ratio and do well, but loads do well without any T3, some do well on T3 only. It is what suits you. This normal use of T4 with a tiny bit of T3 is an idea which doesn't seem to get much attention. You may be someone who could benefit from this. I don't know, but knowing about this protocol is useful info. Here is the Dr Myhill link:


many thanks,marsaday.I crashed into depression with anxiety for 2 years after 18 years on T4 only.Now after 18 months on T3 the same thing has happened.Its time to try a combo & I am going to keep trying to find out what makes me well.

Yes,T3 multi dosing away from food & supplements is a pain.Some take all their T3 once a day,but that didn't work for me.


So you were on T4 for along time and never thought to add T3 as the first step to improvement ?

Seems a bit weird.

If you were on T4 for 18 yrs and were generally ok, i don't think it is the T4 which failed you. Your metabolism changed. This is normal. You get older etc, maybe make more oestrogen, so you convert less T4 to T3 and suddenly you have these anxiety issues.

Certainly worth seeing what more T4 and less T3 is like. If you start to feel a bit better, make changes slowly.

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Thank you very much for these suggestions.I was on thyroxine for 18 years.Spent a few weeks on T4/T3 combo in 2015 & been on T3 only for over 18 months.Settled on a dose of 55mcgs.Raising above this to 60 or more gave me sweats,flushes,made me feel too hot & raised my heart rate beyond comfort.Didn't notice an increase in anxiety.

All went well until I decided to add some T4 back in,as NDT.Tried twice for 8 weeks starting in April 16,then again for 5 weeks starting August 16.

Stopped both times due to anxiety,tachycardia & ectopics.Reverse T3?Adrenals?

Now stuck in a permanent state of depression with anxiety.All other symptoms OK,as before the NDT trials.

Also-significant hairloss on T3.

Very grateful for any ideas!

November FT3 is 6.4 pmol/L (3.80-6.00 pmol/L)

Have reduced dose to 50mcgs T3.Perhaps I should drop some more.Should I introduce a little T4 perhaps?I keep reading that hair folicles need T4.

Am supplementing magnesium,omega3,B1,B2,B6,B12,folate,iron,vit C,CQ10,selenium,zinc,D3


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