Are You Living Life with Thyroid Brain Fog?

Are you living life with thyroid brain fog?

Could brain fog be a warning sign your thyroid is NOT optimally treated?

It’s critical you find out.

Poorly managed hypothyroidism can have a powerful effect on your brain.

Written by Hugh Melnick, MD, F.A.C.O.G.

At one time or another, everyone has suffered from what they would describe as brain fog. The following factors can bring with them a decreased sense of neurological function:

  • Stress
  • Pregnancy
  • Sleep deprivation
  • Illness

Let’s focus on the last item and find out more about how brain fog relates to hypothyroidism.

Critical Mood Deterioration

These three words are how medical experts and research analysts describe the mentally foggy state that many thyroid patients find themselves in. In fact, current studies indicate that an underactive thyroid can take a significant toll on your mental health.

There’s more to hypothyroidism than the physical symptoms we’ve all learned to watch for. The fact of the matter is that over time, a thyroid gland that produces less hormone than it should will affect your neurological function.

Why? Because the hormone deficiency slows everything down, including neurological functions.

This domino effect can leave you with a chemical imbalance that includes symptoms like:

  • Inability to concentrate
  • Detachment from personal relationships and activities
  • Low self-esteem
  • Depression
  • Inability to connect details
  • Short-term memory problems
  • Slowed mental reactions
  • Confusion

As your undiagnosed symptoms worsen, your quality of life also decreases.

Temporary Fog or Something Else?

Brain fog has many causes and thyroid problems are definitely on the list. Anything that causes a misfire in your neurotransmitters can lead to a feeling of forgetfulness or living in a mental fog. But it’s very important to realize when these symptoms might be indicating that you have a serious health problem.

Stress or even trouble sleeping can trigger temporary brain fog. We’ve all been in situations where feeling emotionally overwhelmed or tired leaves us also feeling mentally slower than usual.

The question we need to ask ourselves is: when might it be something more serious? Brain fog can actually signal the onset of disorders and processes in the body that need to be managed and addressed such as:

  • Thyroid Problems
  • Adrenal Failure
  • Menopause

Living Life in a Thyroid Brain Fog

Unfortunately, the neurological symptoms that about 5% of all hypothyroidism patients suffer from are largely underestimated or outright ignored by a lot of practicing medical professionals.

This is not something that can simply be treated with complimentary drug therapy. It takes more than antidepressants to really understand and address this problem – it takes looking at thyroid function as a whole.

Patients often complain that even though they are in treatment for their thyroid condition, they don’t feel better physically or mentally.

Many doctors write this off as a casualty of the adjustment process, but if they look closer, and pay attention a little sooner, these mental changes could be an effective early warning sign of an underlying thyroid condition.

Thyroid conditions are notoriously difficult to diagnose in the early stages. The standard blood tests aren’t accurate and it’s easy to confuse the symptom presentation with other health problems. Search until you find a  doctor who will listen.

The Thyroid

The thyroid gland is a small, butterfly shaped mass of tissue found in the neck, just below the “Adam’s Apple.” Despite its small size, it has a critical role in determining how our bodies function, and, ultimately, how well we feel.The thyroid controls the body’s metabolism, which is the energy supply that is essential for all bodily functions. Think of the thyroid gland as an automobile’s fuel pump. If the pump is not working up to capacity, the car’s engine will not get enough fuel, and will run slowly and inefficiently. Should the pump supply too much fuel to the engine, it will run too fast and eventually burn out. An underactive thyroid gland causes a medical condition known as hypothyroidism.

For some unknown reason, it occurs much more frequently in women than in men, and as many as 15% of the female population may have some degree of thyroid under activity.

Thyroid Symptoms

The symptoms of hypothyroidism are quite common and diverse. They affect the way a woman looks and feels, both physically and emotionally. Without any doubt, an untreated under active thyroid gland can have a profoundly negative effect upon a woman’s quality of life.

Having seen the wide spectrum of symptoms associated with hypothyroidism, it is apparent that they are extremely common complaints, experienced by many women. It is quite possible that either you, one of your friends or a family member is plagued by one or more of these troublesome symptoms. Many times, women with these complaints have been tested for hypothyroidism and were told that, despite their symptoms, they did not have an under active thyroid gland because their thyroid blood test results were within the “normal” range. They may have been told that their symptoms are part of the “normal” aging process or are caused by anxiety or depression. In many instances, they are referred to a psychiatrist for treatment with antidepressants and psychotherapy, but often these treatments may not make a symptomatic woman feel better.

A Common Thread of Progression

Rather than list all possible symptoms of hypothyroidism; I’ve chosen to list one of the most common symptomatic progressions. This is the typical presentation most patients go through:

  • Most symptoms, such as lower heart rate, tiredness, poor memory or difficulty in thinking, and even constipation, are due to inadequate stimulation of the various organs in the body due to insufficient amounts of thyroid hormone.
  • Other symptoms, such as inability to tolerate cold environments, are directly due to the decrease in heat generated within the body by slowed metabolic activity.

Most people with hypothyroidism will experience some of the following symptoms:

  • Slow heart rate
  • Tiredness
  • Inability to tolerate cold
  • Weight gain
  • Emotional depression
  • Drowsiness, even after sleeping through the night
  • Heavy or irregular menstrual periods (in premenopausal women)
  • Muscle cramps
  • Constipation

Later symptoms of hypothyroidism include:

  • Dry, flaky skin
  • Hair loss
  • Impaired memory and difficulty in thinking
  • A deepening voice
  • A numb sensation in the arms and legs
  • Puffiness in the face, especially around the eyes (a condition called myxedema, which is an indication that the disease has become serious)

Subclinical Hypothyroidism

Such symptomatic individuals may actually have a condition known as Subclinical Hypothyroidism. In this clinical condition, a patient may be symptomatically hypothyroid, yet her blood tests may suggest, but not fully support, the diagnosis of thyroid gland under activity. In subclinical hypothyroidism, there is a partial decrease in the thyroid glands ability to produce enough hormones to make the body’s metabolism work at 100% efficiency; hence an individual will be symptomatic. Such individuals may benefit from a therapeutic trial of treatment with a natural prescription thyroid supplement.

There are two basic problems that account for the failure to diagnose many cases of subclinical hypothyroidism. First is that what is considered to be the “normal range” for one of the main blood tests used to diagnose hypothyroidism (TSH-Thyroid Stimulating Hormone) is too broad to diagnose many patients who are symptomatically hypothyroid. In addition to TSH levels, the amount of other thyroid hormones such as T4 and T3, as well as antibodies against thyroid tissue, must be evaluated in any woman having symptoms associated with hypothyroidism.

The second difficulty in diagnosing hypothyroidism is that we, as physicians and scientists, are trained to rely more on objective findings, such as laboratory tests, than subjective factors, such as a patient’s symptoms. Unfortunately, many doctors will not feel comfortable making a diagnosis of hypothyroidism if a patient’s blood tests fall anywhere within what is strictly defined as the normal range, even if such levels may be close to indicating the possibility of an under-active thyroid gland in a symptomatic patient. There are definite “gray zones” that exist clinically; such that a patient’s clinical symptoms may not be completely documented by their laboratory results.

It is important to remember that blood tests only reflect a “moment in time” in the human body and consequently may not always accurately represent its true condition! Therefore, a patient’s symptoms must be considered as being of equal significance as their blood test results in diagnosing hypothyroidism.

In my experience, many women who present with physical and psychological symptoms associated with hypothyroidism will have some degree of improvement when treated with supplemental thyroid medication.

Improvement should be noted in two to eight weeks. Increases in energy levels, sex drive, body temperature and memory are the first changes noted. Water retention also improves fairly rapidly. An increased feeling of well-being may also be noticed, as depression resolves.

Hair and skin begin to improve after 4-6 weeks, but weight loss usually will take quite a bit longer since the body takes time to breakdown existing fatty deposits. When I treat women who have symptoms associated with hypothyroidism, I initially use a natural desiccated thyroid medication (NDT) that has been available since the 1940’s, such as the brand Armour Thyroid Extract U.S.P. It is a combination of two active forms of thyroid hormone, T3 and T4. T4 is the form of the thyroid hormone that is in the synthetic thyroid medications commonly prescribed today. Normally, T4 is converted into T3, which is the biologically active form of the thyroid hormone that actually controls the body’s metabolism. In a significant number of individuals, the body is unable to properly convert T4 into T3. Hence a patient may be clinically hypothyroid, yet have “normal” blood tests. Therefore, I find that a woman’s clinical response to the natural form of a combination of T3 and T4, will often be better than giving T4 alone.

It is of critical importance that a physician be finely attuned to a patient’s symptoms and her symptomatic response to treatment. Thyroid supplement therapy is very individualized, since the dosage requirements are quite different for each patient. A patient’s dosage needs to be reevaluated based upon the degree of symptomatic improvement and “finetuned” as necessary.

The important point to remember is that the evaluation of symptoms is of equal significance to the levels of thyroid hormone in the blood.


The diversity of symptoms can make the diagnosis and treatment of hypothyroidism quite challenging, especially since laboratory tests do not always reflect thyroid gland under activity in a significant number of symptomatic individuals.

If you, a friend, or a loved one experience any of the above symptoms or generally feel poorly, you should speak to your doctor about the possibility that subclinical hypothyroidism may be the cause of such symptoms. After an appropriate diagnostic evaluation of symptoms and laboratory tests, a therapeutic trial of a natural thyroid supplement or any other thyroid medication may provide relief from these troubling symptoms.

Thyroid conditions are notoriously difficult to diagnose and treat optimally. Search until you find a doctor that will listen.

About Hugh Melnick, MD, F.A.C.O.G.

Dr. Hugh D. Melnick is a reproductive endocrinologist who has been treating patients with hormonal and fertility problems since 1976. In 1983, Dr. Melnick founded Advanced Fertility Services, which was the first free standing In Vitro Fertilization Center in New York City and is still its medical director. He has been impressed by the large number of infertile women that he has seen over the years, who are symptomatically hypothyroid, and who conceive after treatment with thyroid medication. Dr. Melnick is one of the incredible experts I interviewed for my book Your Healthy Pregnancy with Thyroid Disease: A Guide to Fertility, Pregnancy, and Postpartum Wellness.

Dr. Melnick’s vast clinical experience together with his own personal experience having hypothyroidism has enabled him to develop a unique approach to the diagnosis and treatment of hypothyroidism. During his many years of clinical practice, he has recognized how hypothyroidism can adversely affect every part of the human body, creating many unpleasant symptoms, which inevitably interfere with a productive and enjoyable quality of life. In addition to his fertility services, he works with thyroid patients at


Huong, T.D., et al. Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study. J Clin Endocrinol Metab. 2013 May;98(5):1982-90.

READ NEXT: Why are there so many unhappy thyroid patients?

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About Dana Trentini

Dana Trentini founded Hypothyroid Mom October 2012 in memory of the unborn baby she lost to hypothyroidism. This is for informational purposes only and should not be considered a substitute for consulting your physician regarding medical advice pertaining to your health. Hypothyroid Mom includes affiliate links including the Amazon Services LLC Associates Program.


  1. randy black says

    does proper dosage of medication and proper T3, T4 levels due to said dosage, correct this issue?

  2. Elspeth Miller says

    i have had thyroid problems for 20 years and dealing with all these problems but when you cant get a Doctors appointment and only get a telephone consultation 3 weeks later after blood results what the hell are you supposed to do . Thyroid is not to be taken lightly it is there to make the body function so Doctors take this seriously we no when our body is not right .

  3. Jackie Clench says

    Hi can Underactivethyroid interfere with your digestion when I eat sometimes about an hour later I feel very hot and uncomfortable sometimes with a stomach ache then I worry which makes things worse

  4. Kimberly Scott says

    Hello, I was diagnosed with Narcolepsy 5 months ago. The meds they are prescribing are barely helping me make it through my work day. What happens to me without meds is what I describe as a trance or a severe brain fog. I do ultrasounds and I can feel this fog come on. I begin to get very sleepy and absolutely cannot think straight. I will remain awake, take ultrasound images on my machine, type nonsense on the screen, all while staring at the screen KNOWING in my brain I am not doing the test right but am UNABLE to make the corrections. Its like cognitively my brain decided to take a nap. It Will allow me to go “through the motions” but not make actual cognitive decisions. This trance lasts about 20 minutes. Then I am able to recover and think clear enough to fix the mistakes I’ve made. The Narcolepsy was diagnosed properly through sleep studies and MSLT however it was determined that some pain medication may have skewed the results. Through a more thorough medical history, a University neurologist believes the trances may be linked to severe depression and sleep deprivation. I too have been tested for hypothyroidism and tests came back positive 1 year, then I quit taking the meds and ever since then all tests have been on the normal range. Long story…sorry. Just wondering if a lower normal range throid level could be responsible for the poor sleep, depression and is manifesting in these trances that are killing me.

    • Hi, it has been my experience to suffer with being tired alot, even after a nights sleep, brain fog, and anxiety and depression. WHEN I forget to take my meds, it’s worse, usually on the weekends due to a change in my work routine. When that happens I will feel very tired for a few days till my thyroid readjust to what’s missing. I would suggest a full thyroid panel of blood work to understand just how the numbers are and NORMAL isn’t always optimal for you.

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