Informational Posts

I’m on Thyroid Medication but Still Feel Tired!

Originally published on 4th April 2016
Last updated on 8th April 2024

Are you on thyroid medication but still don’t feel well? A lot of thyroid patients feel this way. They might even question if their thyroid medication is working at all. 

Many people are often left confused and wondering:

  • Why am I feeling extremely tired on Levothyroxine?
  • My thyroid meds make me tired!
  • Does thyroid medicine make you sleepy?

Their doctor puts them on thyroid medication and tells them they are now adequately treated. They may even do a blood test and tell them that their levels are ‘normal’. So then why do they still feel tired?

Can thyroid medicine make you feel tired?

I'm Tired T Shirt

There are some reasons you can still feel unwell and I’m going to explore the most common ones below.

Related Post: 10 Ways To Solve Ongoing Thyroid Fatigue

1. Your Thyroid Levels Aren’t Optimal

Most doctors will prescribe T4-only thyroid medications such as Levothyroxine and then test your thyroid levels again a month or two later and declare them ‘normal’.

One part of this problem is that most doctors only test TSH levels and this isn’t accurate when getting the full picture of your thyroid health.

In order to know if your thyroid levels are actually optimal, you need a full Thyroid Panel checking, and this should include:

  • TSH
  • Free T3
  • Free T4
  • and if possible: TPOAB and TGAB (thyroid antibodies)

Checking TSH alone doesn’t give us the full picture and can miss a low Free T3 or low Free T4 level, indicating that our dosage of thyroid medication isn’t right.

It also isn’t checking for Hashimoto’s, the most common cause of hypothyroidism, which can cause symptoms too.

If your doctor won’t order the full thyroid panel, do know that it is simple to order these tests yourself. UK thyroid patients can order them from here and a US here.

Now that we know what needs to be tested, let’s explore where they ‘should’ sit to help us feel our best.

Most thyroid patients seem to feel best when their levels are also optimised and not just in range.

When your doctor runs a test and you receive the results, your levels will either fall inside or outside of the range. Ranges are usually given in brackets besides the test result.

However, it is not just about falling within the range. We are looking for something more specific.

‘Optimal levels’ are a more specific section within the given range, which is often very wide and much less specific in comparison.

You’ll find that many thyroid advocacies and progressive medical practitioners agree that when testing a thyroid panel (or “Thyroid Function Test”), a TSH less than 2 or 2.5, and a Free T3 in the top quarter of the range, with a Free T4 mid-range or a little higher is considered optimal. Antibodies as low as possible are also seen as optimal as this signals Hashimoto’s being more under control or ‘in remission‘.

Read more about optimal levels here.

2. Your Medication Isn’t Right for You

Some people respond well to Levothyroxine or Synthroid, the T4-only medications, but many equally do not. You may be on this medication and still feel tired, brain fogged, achy and generally unwell. 

After all, a study in 2018 demonstrated that Levothyroxine was associated with a lower quality of life in those with Hypothyroidism. [1]

So you may well do better on a different type if you’re still not feeling well on T4-only medications such as Levothyroxine.

Other thyroid medication options include adding T3 to your T4, or switching completely to Natural Desiccated Thyroid. I’ve covered all of these in detail here and here.

Especially if you have a full thyroid panel tested, and your Free T3 is low yet Free T4 high in range for example, you would benefit from exploring the possibility of a conversion problem and adding that T3 in. This can be done by adding T3 to your T4 (Levo), or switching to NDT, which has it in. These can be discussed with your doctor.

I support people finding what medicine works for them. We are all different.

Thyroid UK reported:

“Levothyroxine treatment provided total relief of symptoms in 7% of the respondents and significant relief in 41% of respondents. However, 6% of respondents received no relief from symptoms and 40% only slight relief. NDT provides the most relief of symptoms providing 29% with a total relief of symptoms and 57% with significant improvement. However, 10% only received slight relief and 2% no relief of symptoms.”

and that is a huge difference. [2]

If your current doctor isn’t open to exploring other medication options, you may wish to explore other types of medical professionals which may be able to help. See types here.

3. There’s Something Else at Play

Other deficiencies or issues are common if you also have thyroid problems. These can include the below, so they’re worth exploring if you still don’t feel well.

Vitamin Deficiencies such as D, B12, Iron, Ferritin etc. can all give you similar symptoms to low thyroid function, so it’s worth checking these if you are tired a lot, have hair loss, bruise easily, are fatigued etc.

Adrenal dysfunction can also cause havoc in thyroid patients too, without us even realising. Symptoms include fatigue, waking up still feeling tired, not being able to cope with stress very well and craving sugary and salty foods. The most accurate way to test if you have adrenal dysfunction is with a 24-hour saliva cortisol test, to check cortisol levels. If your doctor won’t do this, you can very simply order it yourself and complete it at home. If your doctor won’t check your adrenals, you can very simply order testing yourself from here and here. They should ideally read as stated here.

4. You’re Not Addressing Hashimoto’s

Most of us with hypothyroidism have Hashimoto’s to thank as the cause, yet don’t even know it.

I’ve created a whole article on Hashimoto’s here, and ways to treat it include getting your thyroid levels optimal (TSH, Free T3 and Free T4, Thyroid antibodies) and for a lot of patients, cutting out gluten.

More ways to help Hashi’s are listed here.

Addressing the autoimmune condition that may be causing your hypothyroidism and getting it under control can help with fatigue and managing symptoms.

Getting Hashimoto’s in to remission seriously helped in the management of my symptoms.

5. You May be Taking Your Thyroid Medication Wrong

Many patients take their thyroid medication an hour away from any food or drink, excluding water. The reason being to stop anything else from affecting its absorption. You shouldn’t really eat or drink anything for an hour either side of your thyroid meds, as well as take other medication or supplements, and you should avoid taking calcium, magnesium, contraceptive pills and iron close to it in particular. Take your thyroid medication at least four hours away from these.

Oestrogen, calcium, magnesium and iron bind some of the thyroid hormones and makes them unusable, affecting how much you really absorb. If you’re on NDT, many also state that taking it sub-lingually (dissolved under the tongue) has a better effect than just swallowing it.

See a full article on how to correctly take your medication here.

Some patients on T4-only meds like Levothyroxine also state it works better for them when taken at night, instead of the morning.

6. You’ve Not Got The Right Diet 

You’ve got to nourish to flourish!

Eating and drinking in the right way for your body is often key, too. You can explore whether removing caffeine, alcohol or other food that commonly impacts thyroid patients, helps you too. As well as foods that may be problematic, there are also plenty that we should try to get more of to support our thyroid health and reduce thyroid symptoms. More info here.

Find a thyroid cookbook here.


Considering and implementing these ideas can go a long way in seeing improvements. You see, thyroid medication doesn’t cause fatigue, but it may not be addressing it because it’s not the right type or dosage for you. Beyond that, other issues often coexist that we can explore. Living well with thyroid disease often involves looking at our lifestyles holistically and considering all areas.

Do you still feel unwell despite being on thyroid medication? You can share in the comments below.

Related posts:

6 Ways to Create an Energy-Boosting Morning Routine as a Thyroid Patient

When Thyroid Medication Doesn’t Fix Everything

Be Your Own Thyroid Advocate Book CoverSee also:

The book Be Your Own Thyroid Advocate: When You’re Sick and Tired of Being Sick and Tiredwhich builds on this article in detail. Learn how Rachel reclaimed her life when thyroid medication wasn’t helping.

You can click on the hyperlinks in the above post to learn more and see references to information given.




About Author

Rachel Hill is the highly ranked and multi-award winning thyroid patient advocate, writer, speaker and author behind The Invisible Hypothyroidism. Her thyroid advocacy work includes writing articles, authoring books, producing her Thyroid Family email newsletters and speaking on podcasts and at events about the many aspects thyroid disease affects and how to overcome these. She is well-recognised as a crucial and influential contributor to the thyroid community and has a large social media presence. Her bestselling books include "Be Your Own Thyroid Advocate" and "You, Me and Hypothyroidism".


  • Nat
    March 10, 2023 at 5:14 pm

    Hi there
    I have hypothyroidism and I’m on 88mg LEVO.

    I’m super tired even though i get sleep.
    Joint and muscle pain
    eye pain
    heart palps

    Is anyone else experiencing this?

    • Rachel Hill
      March 12, 2023 at 3:14 pm

      These are really common situations to be in. Have you checked the things mentioned in the article?

    • Amber
      May 1, 2023 at 4:54 pm

      Yes I have most of those. I have just started Levo one week ago. What frightens me most is if I go for a walk heart seems under pressure, I am really scared about this hoping it will be ok when On Lexo longer and stop walking. Had 2 ECG’S and they are ok. I had High Blood Pressure at start of Hypothyroidism.

      • Kate
        July 7, 2023 at 10:27 pm

        Same here Amber

    • Peggy
      May 17, 2023 at 8:25 pm

      Yep! Diagnosed with Hypo THL was 22 ! (should be like 2.5 to 4 somethin like that) I am 68 yr old she put me on lowest dose first, 25 mcg…that seemed to help for 2 mos…then she said my levels still were not low enough at 14 so increased it to 50mcg in early March I thnk it was. I felt ok for a while, then come April got extremely tired, now mid May still extremely tired, I do sleep OK (I have to peep at night but always did that about 3-4 times) but do go back to sleep. I feel worse now I think than before I ever took it. (I am on Levothyroxine) also my body temp was always normally very low I guess because I was hypothyroid, my temp was always anywhere from 96.8 to 97.5. Now it’s 93.3 to 98.6 and I feel hot and sweaty at times throughout the day and liked my old body temp better. Going back to Dr this time a different PA see what she says. The other night I didn’t take the whole pill, I snipped a bit off so it was about 40 mcg not 50, and the next day I felt pretty good, but figured I shouldnt do that so took the regular 50 mcg last night and feel like crap today, was tired as soon as I got up and I slept pretty well. I think I want to GET OFF of this stuff…I feel like crap and think I was better off before I was ever diagnosed and put on this stuff.

    • Janet
      June 26, 2023 at 2:24 am

      Yes I relate to some of the same things. Now I need to take cortexi for the ringing in my ears and hope it is okay with my thyroid meds. I have to worry about everything I take. My doctor had me tested every 4 months but is know retired. Just hope things get better for you and I will pray for you. We just have to trust they will.

  • Crystal Mitchell
    August 21, 2022 at 2:18 am

    I on thyroid medication still feel the same and still having the symptoms. Weight gain, hot flashes, tired sometimes, and hard to focus. I had took two blood thyroid tests still the different doctors still my results is normal and I feel not the same.

  • Louise
    October 26, 2021 at 9:56 pm

    I have Addison disease and now under active Thyroid I’m taking the Thyroid medication but I’m struggling my hair is falling out and I’m lethargic. By 6 pm each night I falling asleep I’m struggling to do my job. Previously I worked hard all day then trained at the gym 4 nights a week. I’m struggling to train at all
    Feeling fed up

  • Karolin
    January 6, 2021 at 2:39 am

    I get awful side effects on any thyroid meds I try. T4 gives me severe migraines doesnt matter which brand, NDT gives me migraines and difficulty breathing and swelling throat. T3 makes me extremly tired to the point where I have to lay down 2 hours after taking it, also get alot of headaches, depression and rapidly changing moods. I get more difficulty concentrating on it than off it. After 3 months I got daily migraines from t3 and had to stop. No doctor knows what to do about me at all. I’ve changed diet to antiinflammatory, gluten and dairy free, minimum coffee. What can I do when no doctor can help me ? I look so old when Im not on meds but I cant take them.

    • Jenell
      June 3, 2021 at 4:20 pm

      T3 does the exact same thing to me. I get so tired.

  • Xtal
    October 22, 2020 at 9:07 am

    Thanks everybody that posted! Earlier this year I started to take levothyroxine after taking blood tests tsh/t3/t4. T3 and t4 were in normal range, but tsh was 12 (supposed to be lower than 5 is what I was told). By Feburary I was feeling better with just 25mcg per day, but my tsh only went down to 6. So the doctor added 1 day at 50mcg and the other 6 days at 25mcg. Blood test 6 weeks later came up as 9! So they added a second day of 50mcg. Then test 6 weeks later came back at 6. So they kept adding 1 more day. I was feeling pretty good at 3 days with 50mcg and 4 days of 25mcg, but I am currently taking 50mcg on 6 days and 100mcg on 1 day per week. I feel completely awful. No energy, hair coming out, weight gain, blood pressure going up, and I’m tired of deciding if I’m going to take a shower or cook food because I don’t have energy for both. I have a doctor appointment in a week and I don’t know what to do if my tsh test comes back as bad again. I might tell them that I’m going to take less so I can function like a human again.

    • Michele
      April 23, 2021 at 5:31 pm

      Listen to YOUR body.
      Everyone functions at different “test” numbers/levels
      You have enough experience with the doses
      So take the amount that makes you FEEL the best.
      Also make sure you are making enough Estrogen, if over 40
      If your Thyroid medication makes you sleep, take it at night.

  • Ann Reilly
    September 25, 2020 at 11:56 pm

    Hi Rachel, I was diagnosed with Hashimoto’s Hypothyroidism back in July 2020 with a noticeable goiter. I was started on low dose Synthroid. 6 weeks after starting the med my endocrinologist wanted bloodwork and all was well and I was to stay on the 50 mcg dose daily. I take it as directed, on an empty stomach with water and wait to eat/drink about an hour. Problem is the last 2 weeks I am feeling extremely exhausted, no energy or ambition to do anything and terrible joint pain/leg pain. I do not take any other meds or vitamins. I am wondering if I should inform my endocrinologist or just stick it out and see if it gets better…. I don’t want to switch to something else and I fear switching the med back and forth may be worse for me? Any suggestions would be greatly appreciated. Thank you so much!

  • Uner
    September 6, 2020 at 3:52 pm

    Whats the dose of nasant iodine and selenium you’re taking ?

  • Mavis
    January 30, 2020 at 3:28 am

    Great blog thank you

  • Judy Taylor
    January 25, 2020 at 3:58 pm

    After taking synthroid I started getting upper stomach pain. Continued with meds for 10+ years. Last 2 years pain along with major fatigue and exhaustion, weight loss (106 lbs at 5’7″)took over my life. After many tests with no answers I thought I was dying.
    I stopped my synthroid and I now feel human. Weight gain of 10 lbs in a month, no major stomach pain, although I still watch my diet for gluten, I wake up and able to function without feeling exhausted. Only drawback is I don’t sleep straight through the night.
    I have not told my doctor I have stopped my synthroid as when I indicated I thought that maybe the cause she blew it off. I’m now hoping this works for the next 20 yrs. I’ll be 85 then and won’t mind death.
    Any other suggestions for keeping me synthroid free and feeling well.

    • Celeste
      September 23, 2020 at 1:05 am

      How long before you felt better? I went off my dose yesterday because I felt light head and tired.

      I Still feel the same- I know it takes time to get out of ones system- just wondering your timeline.

  • Catherine
    January 23, 2020 at 2:53 am

    Amazing blog thanks!

  • Jackie
    January 5, 2020 at 5:25 pm

    I had my thyroid removed about seven years ago due to multiple nodules and cancer could not be ruled out. Been on armour felling good for many of these years and for the last year not well. My hair falling out, exhaustion, stomach issues again, moody, weight gain, and pain are just some of the bothersome issues. I told my doctor in August that I felt I had built up a resistance to my current meds but have not got anywhere with that yet. Any suggestions

  • Teresa. Warren
    November 12, 2019 at 6:59 am

    I’m on thyroid meds and I still feel bad all the time no energy at all.I have no thyroid at all just glands.

  • Susanna
    April 10, 2019 at 6:51 pm

    Hi there
    I’ve been on 225mg thyroxine for over 15 years no problem. The last two years my tsh levels have been yo yo ing from 0.005 to 78. I have been feeling absolutely lousy, fatigue, hair falling out, weight gain and muscle pain in my legs but my GP won’t agree it’s because of my thyroid, my tsh is now 0.05 but I’m still feeling like rubbish and have been for months,
    I have gone away from my doctor and booked an apt to see a top endocrinologist in London. Can you offer any advice on what I should ask hi and what I should be tested for. I have hashimotos but don’t believe I have had any other blood tests done apart from the usual nhs ones. I feel at the end of my tether and am hoping this chap will be the answer to my prayers

  • Naomi
    April 9, 2019 at 8:50 pm

    I’ve been feeling tired for the last two years and I’m only 18. My hairs been falling out excessively too and now it’s so thin. I’m on synthroid but it doesn’t seem to make a difference and I don’t know what else to do because I managed to get my doctor to do a T3 and that was hard because she only does T4 and Tsh but my levels for T3 were in the middle range. Not sure what other options are left. My T4 was on the lower end too like the borderline. But it doesn’t seem to be going up even with Synthroid. It’s only my tsh going down but my T4 not going up.

  • Maria
    March 28, 2019 at 10:03 am

    Hi can you tell me what I can do for me being tired and lethargic all the time I work but through the day and at the end of the day I just want to sleep and have mood swings.
    I’am on levothyroxine 75mg lansoprazole 30mg loratadine 10mg also inhalers.

    • Rachel Hill
      March 28, 2019 at 10:08 am

      HI Maria, if you go through the article and check each of the points covered, it would be a good place to start.

  • Renee
    November 10, 2018 at 4:26 am

    2014 rightcdide thyroidectomy, two months later my hair started falling out. Went AIP, on WP and my adrenal and cortisol fine. How can I stop my hair from falling out??????? Help!!!!!!

  • Rachel Perre
    October 4, 2018 at 6:24 am

    Hi, I had my thyroid removed at the end o 2013-214 due to a cancerous tiny lump on both sides, I’m on thyroxine 150mg Monday to Friday then 100 mg on the weekend. Would I benefit trying natural I do feel tied with no energy, I get checked once a year for it. I have being researching ashwandgha it’s a herb I want to take without stopping the medication.

    • Rachel Hill
      October 4, 2018 at 6:35 am

      Hi Rachel, have you had a full thyroid panel test done recently? It includes free t3 and free t4 and can show whether you’re converting your t4 medication (thyroxine) to t3. A lot of people don’t convert very well and so are left with low free t3. If this is the case, Natural Desiccated Thyroid, a medication containing t3 can indeed help.

    • Estee
      June 18, 2023 at 4:03 am

      Hi Rachel,
      I still have my thyroid and was in remission with normal values when a took a blood pressure herbal combination that had ashwandgha in it. If you research that herb, you will find it can cause a number of thyroid problems. It seemed to cause a severe autoimmune response and so I must be on thyroid forever now. I cannot recommend it but maybe consult a doctor on this one. I am so sorry I used it.

      • cat
        March 12, 2024 at 10:44 am

        Hi there,
        Thank you for your posts and for making me feel very well supported and not alone, trying to keep my job and my sanity, 😀 thank you again


Leave a Reply