TSH is often the first test doctors use to determine whether you have too little or has too much thyroid hormones. Low TSH is linked to an overactive thyroid or hyperthyroidism. Read on to learn about the causes, symptoms, and natural ways of increasing your TSH levels.
Causes of Low TSH & Hyperthyroidism
1) Goiters & Grave’s Disease
Goiters are an enlargement of the thyroid gland, and can sometimes be seen as a bulging in the neck area. Goiters are usually a sign of thyroid dysfunction or iodine deficiency .
Other common causes of hyperthyroidism are toxic nodular goiters (swollen thyroid – also known as Plummer’s disease) and painless (or “silent”) thyroiditis (a condition where the immune system attacks the thyroid gland, causing it to become inflamed) .
2) Mild Iodine Deficiency
There are many different ways that stress can impact your T3 and T4 levels.
For example, many studies have suggested that experiencing negative and stressful life events increases the likelihood of developing Graves’ disease, a common cause of hyperthyroidism [8, 9, 10, 11, 12].
Nonetheless, several animal studies support the idea that stress is a contributing factor in thyroid dysfunction. For example, multiple rat studies have found that stress disrupts thyroid function, although in different ways.
Stress-induced by electric shocks to rat tails led to decreases in T3, T4, and TSH .
A variety of different chronic stressors (including water or food deprivation, cold temperatures, flashing lights, etc.) may also increase T3 and T4 levels .
4) Hormonal Changes in Pregnancy
Because of the hormonal changes and thyroid stimulation that occur during pregnancy, thyroid dysfunction is more common in pregnant women. About 2.1 – 3.4% of pregnant women experience either hypothyroidism or hyperthyroidism .
Studies have also found a variety of adverse effects on the children of women with hyperthyroidism. These include low baby weight during pregnancy (intrauterine growth restriction), premature labor and birth, and low birth weight [19, 20, 21].
5) Low-Carb Diets
In one study, a high-fat low-carb diet also can decrease T3 levels, and both high-fat low-carb and high protein low carb diets can lower TSH levels .
One study found that smokers have lower TSH levels than non-smokers .
7) Certain Medications
Rexinoids (a type of retinoid) may lower thyroid-stimulating hormone levels in rodents, healthy people and cancer patients (possibly by inhibiting TSH secretion and gene expression) [24, 25, 26, 27, 28].
However, one study with 10 patients showed that one type of rexinoid (bexarotene) did not affect TSH levels .
A meta-analysis of 7 different studies showed that metformin reduces TSH levels for hypothyroid patients, but not for people with normal thyroid function .
8) Radiation Exposure
A common treatment for cancer itself is radiation therapy. Unfortunately, radiation therapy puts patients at a greater risk for thyroid cancer, as seen in multiple studies involving children [38, 39, 40].
Limitations and Caveats
A lot of studies in this article talk about associations between low levels of TSH and certain conditions. These studies are relevant but it is important to note that correlation does not imply causation. Just because abnormal TSH levels are linked to specific conditions it does not mean that TSH caused these conditions. It could be the case that the disease caused the abnormal TSH levels, or some underlying factor caused both. Without further studies, it’s impossible to know which is the case.
Symptoms of Low TSH & Hyperthyroidism
A study of 84 hyperthyroidism patients found that the most common symptoms include :
- Increased sweating
- Extreme thirst
- Hyperactive reflexes
- Heat intolerance
Less Common Symptoms
- Muscle weakness
- Sleep difficulties
- Weight loss
- Increased eye sensitivity, leading to crying or tearing up, or painful sensitivity to light (photophobia)
- Increased heart rate (tachycardia)
- Swelling of tissues (peripheral edema)
- “Lid lag” (delay in the movement of eyelids)
- Excess stool production (more than 3x/day)
Hyperthyroidism can also cause psychological symptoms such as apathy, although this was found to be more common in elderly patients (> 70 years old) .
Hyperthyroidism can also cause a number of symptoms that affect the mouth, jaw, and throat, such as burning mouth syndrome, osteoporosis of jawbones, swollen or enlarged thyroid tissue (goiter), and higher chance to develop cavities and periodontal disease .
Health Risks of Low TSH
1) Linked with Worse Mental Health
Low TSH levels may contribute to declines in mental health among the elderly.
In a study with 293 adults over the age of 65, low TSH levels were linked with deteriorating cognitive function .
Another study of 313 elderly adults showed that low TSH levels were associated with worsening cognitive function as well as dementia .
2) Linked to Worse Bone Health
Having higher TSH levels may also support bone health in the elderly.
Low TSH levels were linked to a lower bone mineral density in a study with 674 elderly women .
In a study with 686 elderly women, those with low TSH levels had a much higher risk of fracturing their hip bones or spinal cord .
A study with over 14,000 patients showed that elderly women (but not elderly men) with low TSH levels had a higher likelihood of hip fractures .
3) Linked with Shorter Lifespan
However, although high levels of TSH are generally associated with negative outcomes in adults and children, this might not be the case for the elderly. In fact, many studies suggest the opposite – that in older people, it is actually lower TSH levels that cause problems, while higher levels may be protective.
A number of findings suggest that high TSH levels may be beneficial for living longer.
A very elderly group of people (with a median age of 98) had significantly higher levels of TSH when compared to a control group with a median age of 72 .
For 2,290 elderly adults aged 70-79, those with slightly elevated TSH levels had less difficulty walking, were able to walk faster, and were in better shape than those with normal TSH levels .
A study with 558 adults from ages 85 to 89 found that those with the highest TSH levels had the lowest overall risk of dying .
How to Increase TSH Levels Naturally
1) Increase Your Iodine Intake (If Mildly Deficient)
3) Stop Smoking
Stop or reduce smoking, because smoking decreases TSH levels .
4) Reduce Alcohol
Reduce or stop alcohol consumption . Alcohol use is associated with decreased TSH production.
5) Increase Your Carb Intake
If you are on a low-carbohydrate diet, you may need to increase your carbohydrate consumption .
The following supplements can help increase TSH:
7) Maybe Increase Serotonin
Unsuprisingly, antidepressant medications that increase serotonin have a similar effect. Selective serotonin reuptake inhibitor (SSRI) sertraline increased TSH in one study with 62 depressed patients .
One study with 19 depressed patients treated with SSRIs showed a relationship between TSH levels and symptom improvement. Patients with lower levels of TSH prior to treatment had greater improvements in their depressive symptoms .
8) Avoid Corticosteroids
Studies have shown that glucocorticoids (steroid hormones such as cortisol and dexamethasone) lower TSH levels in both hypothyroid patients and healthy people (potentially by inhibiting TRH) [78, 79, 80, 81].
9) Other Hormones to Look Into
A Word About Conventional Treatments & their Side Effects
The most common treatment for hyperthyroidism in the United States is radioiodine ablation, which is generally safe. Radioactive iodine destroys thyroid cells, and therefore fewer thyroid hormones are produced [5, 87].
Other treatment options for hyperthyroidism include thyroidectomy (surgical removal of the thyroid). Common complications with thyroidectomy are hypothyroidism, low calcium levels (hypocalcemia), and vocal cord paralysis [89, 90].
Antithyroid medications are also commonly prescribed. These include Tapazole (methimazole) and propylthiouracil (which stop thyroid hormone synthesis) or cholestyramine (which promotes excretion of excess thyroid hormones) [5, 87].
One study with 449 Graves’ disease patients showed that side-effects of antithyroid medications include skin rashes, liver damage (hepatotoxicity), and low white blood cell count (agranulocytosis/neutropenia) .
Other side-effects of antithyroid medications are joint pain, swelling, nausea, and vomiting .
Learn More About TSH
This post is part of a three-part series about TSH.
- Find out how the TSH blood test works and what the normal TSH range in part one
- Learn about the causes and symptoms of high TSH and how to lower your levels naturally in this post
Irregular TSH Levels?
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