Relationship Between Testosterone Levels and the Thyroid

Last Updated on

Testosterone is a hormone produced by ovaries in women and testicles in men.

It is often considered a male sex hormone, but its deficiency can cause problems in both – males and females.

In this article, we’re going to talk about the functions of testosterone and how this hormone relates to thyroid health – especially underactive thyroid or hypothyroidism. We’re going to discuss ways to regulate testosterone levels naturally and with the help of medications.

The thyroid gland produces the thyroid hormones triiodothyronine (T3) and thyroxine (T4) which regulate many processes in our bodies, primarily hormonal balance, protein synthesis and metabolic rate.

The thyroid gland is located in the throat, at the base of the neck. If we perform a cross-section of the throat, inside we could find the hyoid bone – or the tongue-bone, the larynx, and the butterfly shaped gland underneath the larynx which is the thyroid.

The thyroid problems can be caused by iodine deficiency, other nutritional issues, genetics, etc. The thyroid gland is most commonly affected by two diseases.

Hyperthyroidism is a condition when the gland produces unusually high amounts of thyroid hormone. The most common cause for this condition is an autoimmune disorder called Graves’ disease.

Hypothyroidism is an opposite disease – it’s a state of insufficient production of the thyroid hormone. Together with iodine deficiency, the main cause of primary hypothyroidism is Hashimoto’s Thyroiditis – an autoimmune thyroid disease. Drug therapies are also a common cause for this condition.

Checking the Thyroid – Self Test

One of the ways to check whether you have an underactive thyroid is to measure your basal temperature once a day.

The basal thermometer should be sensitive enough to measure temperature to one decimal point. These are widely available in pharmacies and mostly inexpensive.

The temperature should be taken once a day for seven days. The key is to take the temperature before taking any food or drink, and prior to going to the bathroom.

Write down the measured temperature every day and add up the numbers, then divide them by the number of days, which is seven.

Normal body temperature is between 36.4°C – 36.7°C or 97.6°F – 98.2°F. If your measured average temperature is below this range, you may have underactive thyroid.

If you feel like your symptoms may mean your thyroid is not working properly – visit the doctor as soon as possible. Many doctors attribute the symptoms to aging only. Make sure that you get all the necessary tests. Insist if needed!

Testosterone Levels and Hypothyroidism

What is the role of testosterone in thyroid health? Well, this “male sex hormone” plays a big role, per several research studies.

Primary hypothyroidism can reduce free testosterone levels and the opposite can be true.

Experts mainly associate hypothyroidism or low thyroid function with lower testosterone levels, and elevated thyroid function – or hyperthyroidism – with increased testosterone.

When it comes to hypothyroidism, we usually think of women since they are eight times more likely to develop this condition, but males are affected too.

With hypothyroidism, the thyroid gland doesn’t emit enough thyroid hormone for our bodies, and the body relies on this hormone to function properly. Without it, a person can experience several physical and mental issues.

Some people have no symptoms regarding the hypothyroidism. Same as testosterone levels, thyroid hormone levels decline in production with aging.

Without a functional thyroid, our bodies wouldn’t be able to break down proteins, or process carbohydrates and vitamins.

When the thyroid is functioning well, the body is usually warm, able to cope with temperature changes, but when the thyroid is underactive – the body is often very cold.

Besides body being cold, some of the most common hypothyroidism symptoms include:

  • Fatigue
  • Sudden weight gain
  • Low blood pressure
  • Erectile dysfunction
  • Depression
  • Arrhythmia
  • Elevated cholesterol
  • Constipation
  • Muscle tension
  • Hair loss
  • Reduced immunity to infections

These symptoms can be caused by many other conditions, but having several of them at the same moment should be the alarm to check the thyroid.

Even though hypothyroidism is commonly diagnosed in women, there are men who suffer from this condition and the symptoms above are also valid for them.

Few of the symptoms that are more common in men include losing hair (including eyebrows and body hair) and decreased libido.

Science behind Hypothyroidism Effect on Testosterone

Primary hypothyroidism often causes low luteinizing hormone (LH) to gonadotropin-releasing hormone (GnRH). The latter is produced in the part of the brain called hypothalamus, and it signals when to release luteinizing hormone.

When it’s low (like in men with underactive thyroid), LH won’t do its job like it’s supposed to, and the function would be stimulating the production of testosterone in male genitalia. This is the most obvious connection between underactive thyroid and low testosterone. As the male genitalia decrease the testosterone production, the final result would be hypothyroidism.

Lab Tests

The best and the required method of testing for low testosterone and hypothyroidism is blood analysis in the lab. You will give a sample of your blood, and several tests will be run. The technician will check the testosterone levels by measuring free and total testosterone levels.  Hypothyroidism is measured with thyroxine (T4) and Thyroid-Stimulating Hormone (TSH) readings.

Hypothyroidism often causes elevated prolactin, which can lower testosterone levels. Elevated prolactin levels are caused by increased TRH, which is a response to underactive thyroid.

The optimum average amount of testosterone for men is 550ng/dL.

Everything below this number is considered low.

Women have significantly lower range – 15 to 70ng/dL, and menopause can lower this by half. This is why many doctors fail to differentiate hypothyroidism from simply aging.

After the menopause, the testosterone production in women will decrease, but it’s not that serious since 75% of the production comes from areas like adrenal glands and peripheral conversion.

Men start to notice a decline in testosterone levels around the age of thirty, and it increases by 1 percent every following year. Most males won’t notice changes, but some of them will; and they will realize their sexual appetite, energy, and metabolism will start to decrease and suffer.

Treatment for Low Testosterone and Hypothyroidism

Often testosterone levels and underactive thyroid can be treated with a healthy diet which commonly includes dietary changes or supplementing strong thyroid healthy herbs. There are various other ways of improving thyroid functionality naturally as well.

However, for more serious conditions, nutritional changes are not an option and medication is often used, such as Synthroid or Armour Thyroid.

The usual treatment for low testosterone is a replacement therapy. Women are often given transdermal creams, and men have much more options including creams, gels, patches and of course – injections.

Natural ways to improve low testosterone and hypothyroidism include more sleep, a better diet, exercising, and less stress, among others. “A Better diet” is far away from restricting and lowering the caloric intake. Our article on the best and worst foods for your thyroid may help in this regard. Stress increases cortisol levels – which is a stress-related hormone which interferes with testosterone and lowers its amount in the body.

Regarding sleep – aim for at least eight hours of good night sleep – it will help to maintain optimal secretion of hormones, including the testosterone.

Complications if Hypothyroidism is Left Untreated

When a person has low testosterone and hypothyroidism that are not cured, some of the complications include:

  • Heightened risk of stroke
  • Heightened risk of heart attack
  • Difficulties in pregnancy that could affect the unborn child
  • High cholesterol

Hypothyroidism can affect life in a negative way, making you very tired, moody, taking all the energy – basically preventing you get up in the morning and lead a normal life. Having hypothyroidism can look like you are depressed to those around you. Doctors often misdiagnose patients and provide therapy for depression – leaving the hypothyroidism untreated, thus complicating the condition even more.

Some people might cope with underactive thyroid for years without knowing it’s an actual medical condition that can be treated. Without sufficient testosterone and thyroid hormone flowing in the body, you might experience fatigue, weakness and be unable to function normally.

A lot of people believe it’s all in their mind. Relief is available; people just need to be informed about their possibilities. Thyroid supplements, for instance, often help a lot of patients.

Besides hypothyroidism, low level of testosterone can be the cause for issues like diabetes, osteoporosis, heart disease, and dementia, among others. It’s extremely important to consult a reliable and knowledgeable people to discuss the best ways to increase testosterone production – and find a good solution for your body.


  1. “Let’s not forget all the men with hypothyroidism”, David Borenstein, MD, Manhattan Integrative Medicine
  1. Reply
    Kellum April 27, 2019 at 4:04 am

    Very informative.

  2. Reply
    Rob March 11, 2019 at 8:46 pm

    Blood test done showing low thyroid, low testosterone and high platelets count and infection. What could this mean?

    • Reply
      dax March 27, 2020 at 2:54 pm

      You might consider looking into Dr. Ray Peat endo/biochemist/physiologist on what all those test results could mean looked at in conjunction.

      He has many youtube interviews and articles online that really go into each factor

    • Reply
      Thyroid Advisor March 19, 2019 at 3:20 am

      Hi Rob,

      Well that definitely not what you want to see in blood tests. The next step would be to figure out why this is the case. Is it with diet or another condition? I would assume medication is part of the plan as well but your doctor likely has the next steps lined up for you.

  3. Reply
    Dan December 13, 2018 at 5:10 pm

    As I read this, Hypothyroidism leads to Low-Testosterone. Hypothyroidism leads to less LH. Less LH, lower Testosterone production. Not just free-T but actual production of testosterone. Less t-4 leads directly to low Testosterone production in the testes for men.

    Hypothyroidism is caused by Iodine deficiency among other causes. Therefore taking supplemental iodine (Lugols type for iodide) should solve many cases of Low-T.

    Since 90% of Americans are Iodine deficient due to our diets and bromine, fluorine exposure – supplementing with Iodine may be the missing link for many men.

    Neither of my two Low-T Doctors suggested Iodine supplementation. I don’t think they have found what is in this article. I’m supplementing with Iodine now. That is how I found this page. I was thinking about this myself and looking for support. I’m supplementing with iodine. See Dr. Brownstein’s surprising advice on higher Iodine supplementation levels. I’m gradually working my way up to 12.5 mg.

    Maybe iodine supplementation will fix my tested and Doctor diagnosed Hypothyroid and Low-T issues? No more Testosterone, HCG injections? (I refused to try the hypothyroid prescription that was offered). Hey, would iodine supplementation lead to the end of my treatments eventually? Back to health?? Wow. Maybe that is all it is. Low iodine started all of this for me.

    Dear Thyroid Advisor – what do you think?

    • Reply
      Thyroid Advisor December 20, 2018 at 7:48 pm

      Hi Dan,

      The idea behind this article was that the thyroid directly effects testosterone levels.

      Having low test levels can be caused by thyroid problems.

      However, thyroid problems can be caused by a multitude of problems – not just low Iodine.

      Having a blood test done to measure the amount of minerals and vitamins in your blood can determine whether you have a enough Iodine and other essential vitamins/minerals.

  4. Reply
    Julius January 23, 2018 at 11:48 pm

    What amazed me about the relationship between Hypothyroidism and testosterone: For decades I had trouble with muscle development. I have been using synthroid for my Hashimotos Hypothyroidism. I recently switch to Naturethroid (a natural bio-identical hormone replacement,) and within 8 weeks, my muscles began to grow! I don’t think that changing from synthetic to natural analog was as much to blame for the growth as was the serendipitous increase in Free T3. I have a conversion problem that kept me from converting the T4 into T3. The Free T3 levels had always been within a “normal” range but at the bottom third of that range. Titrating The Naturethroid, which contains T3 as well as T4, to achieve Free T3 levels in the upper third of the range changed everything. I’ve not checked Free testosterone, but anecdotally — dramatic muscle increases globally, and oddly enough my voice decreased into a deeper tone. Overall more cheerful and clear headed.

    • Reply
      Art April 14, 2018 at 4:20 am

      So I have had trouble with my thyroid since I was a kid I now take 275 mcg of levothyroxin. I have also had low T and started last year on androgel and now I’m taking 1 cc of test cyp a week for my test levels. Seeing this makes me wonder. Any advice from any of you all about my medications wether it be good to continue this or look for an alternate route? I’m 27 years old I have found out about low T at maybe 23 but am now starting treatment.

  5. Reply
    Jason January 5, 2018 at 11:41 pm

    Looking for 1 medication to take to help. I’m on thyroid. Blood pressure & cholesterol n heartburn meds. Hypothyroidism. Would like to find a supplement for all in 1. Instead of a pill for each. 41yr male. Thanks for help

    • Reply
      Julius January 24, 2018 at 12:08 am

      Jason, I’m no doctor, but what you are dealing with makes me think of my Hashiomotos disease. Some of my issues were discussed below in my own post, but I recently connected with a health care provider who educated me about my disease. First of all, most people with low thyroid function are dealing with Hashi. It can be hard to treat properly b/c there can be multiple factors. From your symptoms I am thinking that you should explore gluten intolerance. That alone could be your reason for the heartburn meds. Many people with Hashi also suffer with gluten issues AND low stomach acid. The low stomach acid could contribute to low nutrient absorption and acid/base balance in the blood-that is a whole host of other issues that could be contributing to to conditions. The BP and CHO issues may be symptoms of an under-treated Hypothyroid. I take a natural thyroid hormone now, and my world has changed for the better. There is a good bit of research online that could take you into a deeper understanding of what is happening. One source is:”Stop The Thyroid Madness.” Find that site and get to work. For what it is worth — I only take one pill. Good Luck — p.s. my post mentioned is still awaiting approval so it may not be available just yet.

      • Reply
        Lg April 23, 2019 at 4:25 am

        I’m a 36 year old woman and was struggling with major irritability, fatigue, not seeing results in gym, weight gain, fat gain, no sex drive, moody, difficulty sleeping, always feeling hungry no matter how much I ate, anxiety coming in, difficulty getting a full breath in, a week of body aches, muscle pain, and finally alopecia areata pushes me to see a doc. Tests say I have low testosterone and low t3 t4 was fine. Doc put me on a thyroid med and testosterone pellet implant. First couple of weeks my energy came back though I haven’t been back at the gym and seeing my energy level drop again possibly bc I’m not active enough. Used to workout 5-6 days a week. Single mom with a toddler so I’m guessing the pregnancy and birth did a number in my body. Hair hadn’t grown back in several months. Can’t pin point what’s going on. So frustrating. Going to try and eat better and not stress so much. Sleep habits need to majorly improve.

  6. Reply
    Chuck November 4, 2017 at 3:28 pm

    I seen him for ED.sent me for blood work and looked at all aspects..didnt see anything abnormal..i had a copy of levels of hormones..but me and my gal have been scratching our head..she knows it’s not in my ..still confused.

  7. Reply
    Chuck August 27, 2017 at 8:45 pm

    Had blood work doc says it looks normal but still can’t achieve erection when it’s time,morning wood is impressive tho.Help me out here.had thyroid cancer I’m on.300 mcg at weight of 250.. any answers would deeply appreciated

    • Reply
      Jeff September 20, 2017 at 11:09 pm

      What blood tests did you have done? If only a TSH test, you don’t have the entire picture. Free T3 and Free T4 blood tests are necessary to really know what’s going on. The TSH test is a PITUITARY test. It’s just an indirect measurement of thyroid function and should NOT be used exclusively to determine true thyroid function. Is your TSH blood level around 1.0 uIU/L? The official range is 0.3 to 3.0. Anything over 1.5 should be explored further.

      Just because a doctor says that your lab results were “normal” doesn’t help. Get the exact value. Many doctors don’t know how to interpret thyroid lab tests, assuming that if it’s in the normal range, it’s normal. Not true. Same with testosterone (total) which has a range from 241 to 827 ng/dL. Mine was 245 so I’m “normal”. Ha!

      You had thyroid cancer. Did they remove your entire thyroid gland? You’ll want full replacement of thyroid meds, and not just T4 (an inactive, storage hormone that requires conversion to T3). To be taking 300mcg of levothyroxine (T4) without symptom resolution would suggest that there are absorption issues.

      What time of day are you taking the med? Are you taking it on an empty stomach? T4- isn’t completely absorbed (80%) and can be as low as ~40% if you take it with foods containing magnesium, iron, calcium. You CAN take T4-only meds at bedtime because T4 is slow to begin working, unlike T3, which begins pharmacological activity within several hours.

      Some people don’t convert T4-only drugs very well. There are genetic factors involved. Considering that the normal, healthy thyroid gland produces 100mcg of T4 and 10mcg T3 daily, with a total daily output of 30 mcg of T3 from T4 to T3 conversion in various tissues, it’s not good medical practice to ignore supplementing with some T3.

      Adding some T3 SHOULD have a direct impact on increasing your testosterone levels. Monitor your Free T3 and Free T4 so that they’re at least 50% in range.

      Lastly, do an inventory on what supplements you’re taking. Keep in mind that magnesium, zinc and vitamin D contribute to the testosterone picture. These levels must be adequate for thyroid hormone to work effectively in support of the gonads.

    • Reply
      Thyroid Advisor August 28, 2017 at 5:16 pm

      Hi Chuck,

      300 mcg of synthroid (I’m assuming) is a big dose! You must really have an underactive thyroid. Did your doctor just do a thyroid panel or did he run testosterone level tests as well?

    Leave a reply