Brain Fog: What is brain fog to you? How would... - Thyroid UK

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Brain Fog


What is brain fog to you? How would you describe it? For me, it's not just about forgetfulness, loss of words, what was I doing, etc. but more about how my head 'feels'. It feels heavy, and 'foggy' like I'm in a daze, sometimes my eyes feel blurry and bright lights hurt. Some noises sound amplified. To me, the forgetfulness is really not a big deal, it's more about how my head feels, and it is relentless for so long now, years. So I thought I'd ask to see if we're on the same page or is this feeling I have different, and maybe it's something more serious. : \

Thank you.

22 Replies

When it was at its worst, I might be driving along a road I'm very familiar with and couldn't work out in my head how to get to where I'm going. It was as if that part of the map in my brain was missing. That was the scariest part. It has got better being on the correct dosage.

infomaniac in reply to lisabax

Driving has become a nightmare for me too. Last weekend I was going somewhere I hadn't been for a while (only 10 miles away) and I had to ask my husband how to get there! Once he started telling me, it eventually clicked. This is my experience with Brain Fog-I just feel slow and dim-witted. Also, I have read loads of stuff on Thyroid matters but only a teeny bit seems to have stuck and i feel like it's all jumbled up in my brain!

Weirdly though, I am a whizz at quizzes, crosswords, IQ tests etc.

You have just described my brain fog! It's almost as if I am in a "sensory overload" state. I will add that I also suffer from migraines and the symptoms of both migraines and brain fog overlap somewhat.

I have always had problems with bright lights/noise/busy places, everything feels dream-like/unreal and I kind of drift off a bit.

Like lisabax, I too have suddenly lost my way when driving a familiar route, I still don't like driving when it's dark as I can still lose my bearings quite easily. It is an awful feeling, suddenly not knowing where I am.

I find that everything takes more effort. Things that used to be easy have to be thought about and broken down into smaller sections, even then I might forget half way through. I now need to write lists but unfortunately I forget where I put them!

I often feel as though I am stuck at half speed, it takes longer to process information and I can't cope with multiple people or events.

I feel cheated and want my old self back, occasionally I catch a glimpse of the old me which gives me hope that things can improve, but also shows what is missing.

Enough retrospection back to coping with the everyday.

I can relate to all of this. Yes, the simplest things like making dinner wear me out. I put chores off because it feels so draining. I have to rest and pause. I used to wake up on the weekend and just go to town cleaning and sprucing the house, ready to take on the next task like gardening, whatever. Now I drag me feet. I used to be very creative and would implement what I wanted to do. That is all virtually gone. We went pick paint colors last year and I thought I was going to get sick.

I feel like an old person, yet I see older people than me and they've still got it going on. I feel like I know I could be "me" again if I could just find the right doctor to help me. I wish they wouldn't prolong office visits, charge me an arm and a leg, and still not get anywhere, I think that somewhere in that price tag warrants just a phone call to say How are you doing? and discuss. That'll never happen.

I just want this brain fog to go away, this blurry surreal feeling behind the very eyes that take me through the day and night. I feel better when they're closed. I used to love to carry on conversations, but for years I find myself almost falling asleep instead of being engaged. Holidays wipe me out, for a week of feeling SO bad. I am considering a vacation for Thanksgiving and Christmas, the whole prep for them overwhelms me. STRESS. We live in such a stressful time, it's all around us. Hard to shake.

When I was first Dx w/Hashimoto's last Sept, I thought, Thank God! Now maybe this is why I feel the way I do! But no....T4 isn't helping my brain fog. I am loaded up with antibodies, and GF for months didn't help it at all. Still >600.

I'm going to try NDT in a few weeks. I hope it helps, but I'm cautiously optimistic.

Very good question!

I struggled to explain this feeling to people who would ask for quite some time. Now I tell them it's a combination of two things.

That "wrong side of the bed" feeling, when your alarm goes off at your deepest phase of sleep. Stringing a sentence together requires dedicated thought, very groggy, deep headache and struggle to put 2 and 2 together.

The other part for me is similar to the typical symptoms of being "high". Forgetfulness is also a large part for me, and I'm just typically not engaging to have a conversation with! I also feel a small silver lining is this hindering of cognitive function chills me out a bit more. It's a sad concept to consider, but not thinking can be blissful at times!

marvalrus in reply to mattioso

Yes! I have tried to describe it before as a feeling of still trying to wake up. Like, when you get out of bed, you're still a bit tired and momentarily as you get yourself ready you just like kinda automatically 'wake up' ready for the day. My problem is I don't get that anymore. I wake up and my head just never gets into that gear. It's stuck! I remember if I got a refreshing sleep I'd wake up just ready for the day. Daggone it, I never get that feeling and I'm so sick of it. If I go to bed late, boy do I pay for it, so I do make sure to get decent # of hours sleep.

And Yes! LOL, it's like a "high" feeling like your "inside your head" - I can't stand it! So glad to hear someone else say this. Of course the forgetfulness, etc goes with it, I really don't care much of it, it's the feeling part of it that is maddening.

Brain fog for me starts with my face feeling numbed; like it struggles to remember how to pull an expression.

My responses to others are vague and I need to get them to repeat the question before it finally sinks in... then I struggle with the words to reply. It not so much that I don't have the vocabulary; more like I get stuck between words with the same definition, coming out with a stutter instead.

Mentally and physically this condition is like wading through treacle.

Can I just say here that brain fog can be a symptom of growth hormone deficiency, and when people get GH replacement they can suddenly feel sharp again. Here's a research paper and a personal story (someone I know)

It may be a mistake to see everything in terms of your thyroid. If your pituitary is faulty and causing your thyroid dysfunction, it may be causing deficiencies in growth hormone and cortisol too. Anyway, it might be worth getting checked out.

That is interesting, thank you. L-Glutamine supposedly boosts Growth hormone. Supposed to take it in the morning.

One description I've found as I've got improvements, is that my curiosity returned. My house is full of books, and with brain fog I've been unable to read - can't concentrate, with weakness it's hard to hold a book in place, anyway. But actually I think the biggest reason was that I wasn't curious. With a recent dose change I now often pick books up to look at without really thinking about it. And I wake up thinking "I want to do something nice today", whereas before I just wanted to cope.

I think brain fog is very like being stoned. I agree with a poster above who said it chills you out. I sometimes wonder if the reason I've felt comfortable most of my illness is that I've effectively been sedated.

The most obvious symptom has been being unable to hold ideas in my head. Often I will be thinking something, another related idea will come to me, and then I'll forget what I was thinking about. At times when this is bad I can't even plan a simple meal or to get dressed. I find myself thinking things like "that is the tricky part about that situation", and by the time I've thought that, I've completely forgotten what the 'situation' was! It might have been advice for a friend, international politics, home improvement!

The scariest bit is knowing you can't really perceive it. Like I play a few solitaire games, and I'm a far worse player now. I don't have the mental quickness, but I don't feel any different. Several times when I've had dose changes my brain fog has cleared a lot. And I'll think, oh my goodness, I didn't realise that I even had this brain fog!

I've copied/pasted my own description of brain fog from an old post written some time ago:

I just didn’t feel “with it”, if that makes sense. It very slowly crept up on me, and it was only after I felt better that I realised just how bad it was.

I couldn’t remember names of lifelong friends. I’d lie in bed and try to remember what their children were called as an exercise (instead of counting sheep!), but couldn’t manage that. I would look at an ordinary object, like a book, and couldn’t think what the word was – it felt like it was on the tip of my tongue, but I just couldn’t get it. I would think about that object for as long as I could put up with it, and then gave up and asked my husband because it was SO frustrating not remembering a basic word. When trying to explain that to people, so many say “oh yes, I do all that all the time”, but it is totally different.

I banned myself from driving for quite a while because I couldn’t trust myself to keep safe. I couldn’t remember which colour on a traffic light meant I had to stop or go. I didn’t trust myself to slow down, turn at junctions or anything.

I took my husband to GP and hospital appointments because I couldn’t get the words out that I was trying to say, couldn’t remember what I wanted to say (even though I usually had a written list). I wasn’t safe driving myself to appointments anyway, I couldn’t even look at the money in my hand and be able to work out the combination of coins to pay for parking. I used to practice counting money at home, and it just didn't "compute" in my brain - I couldn't work out what 5p and 10p added up to.

Even if I was doing OK talking, I would suddenly totally forget what I was saying (another thing that other people say they do but, again, it just isn’t the same).

I wasn’t safe cooking because I would forget that I had left something on the hob cooking. When talking to fellow-foggy people, they’ve said similar things about doing daft stuff. It was actually quite distressing though.

I know exactly what you mean about forgetting which colour on a traffic light means go! I have banned myself from driving, too, so am looking at pedestrian crossings. It's even more confusing, because green means I can go, and red means the cars can go. So then I'd get mixed up which set of people were allowed to go. I walked out into roads a few times, but luckily there weren't any cars that day!

Speaking of cars, at my worst, I couldn't see them at all. Standing at the roadside the flow of cars going past seemed like a continuous stream of movement. Like a cross between a blurry train or a snake going past. I couldn't really determine which were separate cars or how fast they were going.

I relate to what a poster above said about overstimulation. I feel like there are maybe a hundred, or even a thousand tiny details to notice if you're walking along a path or sitting in a restaurant. But I can only comprehend and process a small number of them. My brain isn't quick enough to catch it all. I'm still not really well enough to enjoy a meal in a restaurant, because all my energy is taken up understanding the basics, dealing with the menu, and the music, and then cutting up my food, etc. When I get home I realise I didn't even notice the taste of the food or if it was good.

I know exactly what you mean about the traffic lights! I'd forgotten that! I used to chant to myself "Red means stop, Green means go!" - but as you say, not much use on pedestrian crossings. (not forgetting indicators, I often confuse left and right)

I only drive short distances now and never at night. Driving does still require so much concentration that I am always exhausted after even a short drive.

BeansMummy in reply to annie-7

annie-7 - am laughing at "red means stop, green means go" - I used to keep repeating that in my head, but it still didn't make sense!

SilverAvocado, your description sounds like me so much. It is so hard to describe to someone who has never experienced it.

Thankfully, mine has improved immeasurably now. I went for my last neurology appointment without my husband, and the neurologist wrote in my letter to my GP that it was nice to have a coherent conversation with me (the first she had ever had).

Brilliant description Marvalrus, mine feels exactly like this.


Head feels stuffed with cotton wool, it's a struggle to think clearly .. everything slows. Awful. The fog has gone, but the memory problems remain.

Does anyone have an idea of what biochemical process causes it?

marvalrus in reply to Hidden

I have memory and fog. I'd prefer to get rid of the fog first! Memory part doesn't 'hurt'. Fog part does. What made the fog go away for you?

My brain fog is like heavy pressure like feeling in head, ears- so. I agree that is is like a feeling


I think it was going rigorously gluten free that got rid of the brain fog. I did take selenium at that time as well, but my instinct is that it was the gluten that did it.

When I was at work, I'd look down at figures on the page on my desk but by the time I'd look up to the screen to input them on the computer I'd forgotten them, nightmare!!!

It felt like trying to think was like wading through treacle.

Luckily mostly gone now thanks to supplements like b12 and overhauling diet generally to healthier one prob helped too. Still get occasional treacle moments though if do too much (physically)

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