Cleveland Clinic
my.clevelandclinic.org › health › diseases › 23544-subclinical-hypothyroidism
Subclinical Hypothyroidism: Symptoms & Treatment
September 4, 2025 - Subclinical hypothyroidism happens when you have elevated thyroid-stimulating hormone (TSH) levels with normal levels of the hormone thyroxine (T4).
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC5922674
How to interpret thyroid function tests - PMC
For example, both fractionated and unfractionated heparin activate endothelial lipoprotein lipase with hydrolysis of triglycerides and an increase in circulating free fatty acid levels that, in some individuals, leads to displacement of T4 and T3 from TBG, thus raising free (but not total) TH levels. Interestingly, such changes are not generally associated with clinical thyrotoxicosis, and TSH is usually normal.
Videos
03:27
I Have Symptoms of Hypothyroidism but My TSH Is Normal | UCLA ...
01:43
TSH and T3/T4 - Whats the difference? Lab Values/ABG - Shorts | ...
05:19
High TSH Levels: What Should You Do? - YouTube
Causes of normal T3,T4 levels but low TSH levels - Dr ...
06:41
Thyroid Stimulating Hormone: Lab Values for Adults, Nursing School ...
16:21
15 Signs of HYPOTHYROIDISM You Can See: Doctor Explains - YouTube
Medscape
emedicine.medscape.com › tools & reference › endocrinology
Euthyroid Hyperthyroxinemia: Practice Essentials, Pathophysiology, Etiology
Euthyroid hyperthyroxinemia is defined as a condition in which the serum total thyroxine (T4) and triiodothyronine (T3) concentrations are increased, but the thyroid-stimulating hormone (TSH) concentration is normal and there are no clinical signs or symptoms of thyroid dysfunction.
Consensus
consensus.app › questions › very-high-tsh-but-normal-t3-t4
Very High Tsh But Normal T3 T4 - Consensus Academic Search Engine
These studies suggest that very high TSH but normal T3 and T4 levels can be due to factors such as macro-TSH complex, inadequate L-T4 therapy, pituitary alterations, or partial peripheral resistance to thyroid hormone action.
American Thyroid Association
thyroid.org › home › thyroid function tests
Thyroid Function Tests | American Thyroid Association
June 8, 2020 - This is because estrogens increase the level of the binding proteins. In these situations, it is better to ask both for TSH and free T4 for thyroid evaluation, which will typically be in the normal range.
UCLA Health
uclahealth.org › medical-services › surgery › endocrine-surgery › conditions-treated › thyroid › normal-thyroid-hormone-levels
Normal Thyroid Hormone Levels - Endocrine Surgery | UCLA Health
A normal Total T4 level in adults ranges from 5.0 to 12.0μg/dL. A normal Total T3 level in adults ranges from 80-220 ng/dL. Free T3 assays are often unreliable and not routinely used to assess thyroid function.
MedlinePlus
medlineplus.gov › home › medical tests
Triiodothyronine (T3) Tests: MedlinePlus Medical Test
But if your TSH and free T4 levels are also normal, you probably don't have a thyroid condition. High T3 levels (free or total) may mean you have hyperthyroidism (too much thyroid hormone).
Cleveland Clinic
my.clevelandclinic.org › health › diseases › 14129-hyperthyroidism
Hyperthyroidism (Overactive Thyroid): Symptoms & Treatment
September 11, 2025 - Thyroid blood tests: Blood tests can check your thyroid hormone levels. When you have hyperthyroidism, levels of the thyroid hormones T3 and T4 are above normal and thyroid-stimulating hormone (TSH) is often (but not always) lower than normal.
Reddit
reddit.com › r/hypothyroidism › high tsh, but normal t3 and t4
r/Hypothyroidism on Reddit: High TSH, but normal T3 and T4
February 28, 2023 -
Hi all! I managed to convince my doctor to send me for bloodwork. I didn’t get the chance to talk to him about my results yet (he had to postpone our appointment), but I did receive the results anyways.
My TSH levels are high (5,53 mU/L), but my T4 and T3 levels are within normal range (respectively 14 pmol/L and 5,2 pmol/L). My doctor sent me a request to get more bloodwork done at the end of March.
Obviously, I will talk to my doctor, but I was wondering if, in your experience, you can have symptoms of hypothyroidism while still having T3 and T4 levels in the normal range. My symptoms are mostly around feeling tired, sensitive to cold, lots of hair loss, heightened anxiety. I don’t have weight gain so far, which seems to be a telltale sign for a lot of people.
Top answer 1 of 5
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Absolutely we can have hypo symptoms when TSH is High, but T4 and T3 are normal! The time to begin treating hypo is when TSH is High. If we wait until T4 and T3 are Low, then we may develop very unpleasant symptoms and possibly even other health conditions. I briefly went clinically hypo (Low T4 and Low T3) and had awful digestive symptoms and heart burn. I had never had heart burn before! I also felt depressed and unmotivated. I was surprised by how long it took my mental health to get back to normal. When you are being diagnosed with hypo, they often want to re-check your thyroid hormone levels to confirm that TSH is staying Abnormally High. Once they confirm this, then they are likely to prescribe thyroid medication. They know that the High TSH wasn’t just a fluke, that it’s here to stay, and that you can benefit from medication. If you are pregnant or trying to conceive, TSH needs to be below 2.5. If you are pregnant then Dr should likely prescribe thyroid medication immediately instead of waiting to re-test. The fetus uses our thyroid hormone to grow and develop normally during 1st trimester. Sometime after first trimester you still need normal range TSH to be as healthy as you can be, but baby’s thyroid gland will likely be producing thyroid hormone for baby.
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For TTC, my Dr wanted to get TSH below 2.5. My understanding is that the T4 and T3 ranges are quite wide, so whilst you are in range, you might be at low end for your age group or for TTC specifically. I am still learning about all this, maybe someone else can provide a better response.
NCBI
ncbi.nlm.nih.gov › books › NBK83492
Introduction - Screening and Treatment of Subclinical Hypothyroidism or Hyperthyroidism - NCBI Bookshelf
Most patients who have a mildly elevated TSH have a normal free thyroxine (T4) level. The treatment of such patients is controversial, particularly when they have few or no symptoms and no other clinical evidence of thyroid disease. Less frequently, clinicians encounter patients who have a ...
Healthline
healthline.com › health › subclinical-hypothyroidism
Subclinical Hypothyroidism: Treatment, Symptoms, Diet, and More
February 2, 2023 - TSH triggers the thyroid, a butterfly-shaped gland at the front of the neck, to make the hormones T3 and T4. Subclinical hypothyroidism occurs when TSH levels are slightly elevated but T3 and T4 are normal.
PubMed Central
pmc.ncbi.nlm.nih.gov › articles › PMC5771276
Subclinical Hypothyroidism – Whether and When To Start Treatment? - PMC
It represents a state with increased values of thyroid stimulating hormone (TSH) and normal values of thyroxine (T4) and triiodothyronine (T3) [1]. In most cases, patients with SH have no symptoms that would indicate this disorder, so diagnosis is made based on laboratory findings [2]. As the ...
University of Michigan Health
uofmhealth.org › home › our care › specialties & services › hyperthyroidism & graves’ disease
Hyperthyroidism & Graves’ Disease | University of Michigan Health
A high TSH level indicates that the body does not have enough thyroid hormone. A TSH level lower than normal indicates there is usually more than enough thyroid hormone in the body and may indicate hyperthyroidism.
Verywell Health
verywellhealth.com › interpret-your-thyroid-test-results-3231840
Thyroid Blood Tests: Types and What Results Mean
May 15, 2000 - When levels are normal, the pituitary gland stops producing TSH. The TSH test measures how much or how little TSH there is in the bloodstream. Thyroxine (T4) is one of two hormones produced by the thyroid gland. It is an inactive thyroid hormone that freely circulates in the bloodstream, ready to be converted to the active form called T3.
Reddit
reddit.com › r/thyroidhealth › what causes high tsh but normal t4?
r/thyroidhealth on Reddit: What causes high TSH but normal T4?
August 26, 2022 -
My TSH is 10.15 (range .5-4.3) and my Free T4 is 1.1 range (.8-1.4) However, I am having many symptoms. I have been in contact with many doctors and they don’t really know what is going on. Does anyone have any suggestions or have been through this situation before? I started 25mcg levothyroxine 5 days ago but since my Free T4 is normal I am doubtful that will help.
Top answer 1 of 17
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Your pituitary can manage to keep your T4 levels up by constantly poking and prodding your thyroid while it is exhausted. Imagine a factory that has to make 1,000 thing-a-ma-bobs a day. Now say that factory is running smoothly with 50 thing-a-ma-bob assemblers working a normal shifts of 8 hours 5 days a week. Then a few of them quit, or pass away, or retire, or whatever. The manager, Mr Pituitary, gives a speech to the remaining 45 or so worker about putting in a little extra time and working harder to make up the slack. The factory still makes it’s 1,000 thing-a-ma-bobs and everyone manages though they’re a little extra tired. But then, another guy retires, and it’s getting a bit tough, so some guy starts putting in an extra shift each week. Then the assembler putting in the extra shift falls asleep behind the wheel, and now the thing-a-ma-bob factory is down another worker, but they still need to get out that 1,000 thing-a-ma-bobs every day. Then another few assemblers quit because they are becoming unhappy. So the manager, Mr Pituitary, just starts yelling at all the remaining assemblers constantly and insisting they put in 10 hour shifts 6 days a week. The factory is still pumping out those 1,000 thing-a-ma-bobs a day for now, but it can’t keep it up. Soon more employees are going to quit or hurt themselves. It isn’t sustainable. A little levothyroxine will let it relax and work at a more manageable pace.
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This is common with Hashimoto’s which is an organ specific autoimmune disease that affects the thyroid and causes secondary hypothyroidism, which means that the hypothyroidism is caused by the Hashimoto’s. You need a doctor that will treat your symptoms and TSH lab, while also testing your T3 and reverse T3. Some people with Hashimoto’s do well on just T4, some need that and T3.
British Thyroid Foundation
btf-thyroid.org › subclinical-thyroid-disease
Subclinical thyroid disease
Learn about subclinical (borderline) thyroid conditions
Medscape
emedicine.medscape.com › tools & reference › endocrinology
Hypothyroidism Workup: Laboratory Studies, Imaging Studies, Screening
Patients with elevated TSH levels (usually 4.5-10.0 mIU/L) but normal free hormone levels or estimates are considered to have mild or subclinical hypothyroidism. Primary hypothyroidism is virtually the only disease that is characterized by sustained rises in TSH levels.
HealthCentral
healthcentral.com › condition › thyroid › thyroid-gland-function-tests
Interpretation of Thyroid Tests
June 1, 2020 - Sometimes the diseased thyroid gland will start producing very high levels of T3 but still produce normal levels of T4. Therefore, measurement of both hormones provides an even more accurate evaluation of thyroid function.
NPS
nps.org.au › assets › fa172d98f69769b8-d253ad676cdd-6f85b7bb7adf6b07a897038044b88b7bd93037a211bf0756d6ca9a0a05fd.pdf pdf
12 | Volume 34 | NUMBER 1 | february 2011 www.australianprescriber.com
It is not uncommon to find a raised TSH but normal free T4. In most cases this suggests autoimmune thyroid disease. This subclinical hypothyroidism is more likely to progress to · overt hypothyroidism when higher levels of TSH and thyroid