Hypothyroidism and insomnia: what is the connection?

Hypothyroidism and insomnia: what is the connection?

Typically, doctors associate difficulty sleeping with an overactive thyroid rather than an underactive thyroid. However, limited evidence suggests that hypothyroidism may also be linked to sleep problems.

There is little research on the relationship between hypothyroidism and insomnia, and existing research shows mixed results.

A study indicates that hypothyroidism is associated with, but does not directly cause, insomnia. A older, smaller study did not find a correlation between the two.

This article discusses whether hypothyroidism is linked to insomnia and why there might be a link. It also explores how people can relieve symptoms.

There may be a link between hypothyroidism and insomnia. A study 2019 explored the relationship between subclinical hypothyroidism and sleep quality.

Subclinical hypothyroidism is an early, mild form of the disease that does not meet the criteria for an official diagnosis of hypothyroidism.

After comparing the sleep of 2,224 people with subclinical hypothyroidism with 12,622 people with healthy thyroid hormone levels, the authors found several correlations. In general, people with subclinical hypothyroidism had:

  • shorter sleep duration
  • longer sleep latency, which is the time it takes to fall asleep
  • less satisfaction with sleep quality

Researchers also found that people with both subclinical hypothyroidism and poor sleep quality were more likely to be female, younger, or have low body weight.

Older search from 2014 also examined the possible link between subclinical hypothyroidism and poor quality sleep, but the sample size was smaller and less diverse. Participants included 682 men, 38 of whom had hypothyroidism.

Data analysis revealed no association between thyroid hormone levels and poor quality sleep. However, due to the limitations of this study, it may not be accurate.

Subclinical hypothyroidism involves high levels of thyroid-stimulating hormone (TSH). When thyroid levels in the body are low, the part of the brain called the hypothalamus causes the pituitary gland to release more TSH.

When TSH reaches the thyroid gland, it stimulates the gland to make more of the hormone known as free thyroxine (T4).

People with subclinical hypothyroidism therefore have typical blood levels of T4 and high levels of TSH, which may mean that they have no or mild symptoms of hypothyroidism.

Researchers don’t fully understand how high levels of TSH can lead to inappropriate sleep, but they do offer a possibility theory.

This connection between the hypothalamus, pituitary and thyroid is the hypothalamic-pituitary-thyroid (HPT) axis. As a person falls asleep, the HPT axis becomes more active.

This increases the release of TSH, which stimulates the thyroid gland. Under certain physiological conditions, this thyroid stimulation can lead to sleep disturbances.

Although it is not known whether hypothyroidism can directly cause insomnia, it is possible that the disease indirectly disturbs sleep. A person with hypothyroidism may experience:

Physical discomfort

The physical symptoms of hypothyroidism can sometimes disrupt a person’s sleep. For example, if a person experiences joint or muscle pain, sensitivity to cold, or anxiety, they may have trouble sleeping.

A older study from 2011 indicates that insomnia is more prevalent among people who have more health problems. With this in mind, the wide range of symptoms produced by hypothyroidism can negatively influence sleep quality.

Medication side effects

Doctors treat hypothyroidism with thyroxine, which increases low levels of thyroid hormones to relieve symptoms of the disease. At the correct dose, it is an effective treatment for many people.

However, if someone takes more than they need, they may experience side effects, including:

  • inability to sleep
  • anxiety or nervousness
  • Increased appetite
  • to be hot
  • tremor
  • racing heartbeat

Other health issues

Hypothyroidism is associated along with other health conditions that can disrupt sleep, such as obstructive sleep apnea (OSA), which causes breathing to temporarily stop and restart repeatedly throughout the night.

OSA can cause daytime fatigue, frequent awakenings, or difficulty staying asleep. Others sleeping in the same room may notice snoring, choking, or gasping sounds if someone has OSA.

Hypothyroidism is also associated with the symptoms of restless legs syndrome, which causes unpleasant crawling or tingling sensations in the legs when someone is resting.

What helps insomnia depends on what’s causing it. For those with hypothyroidism, a doctor may suggest:

  • start treatment with thyroxine to relieve physical discomfort
  • lowering someone’s thyroxine dose to a more comfortable level if they are having side effects
  • testing for other conditions that may cause insomnia

It is important not to increase or decrease the dose of thyroxine without first talking with a doctor.

If starting or adjusting a person’s thyroid medication isn’t helping, a doctor can look for other potential causes. They can ask someone when their insomnia started, how often it happens, and any changes that happened in their life during that time.

If a doctor suspects a sleep disorder such as OSA, they may refer the person to a sleep study to diagnose it. Alternatively, if the insomnia is associated with another physical or mental health problem, the person can start treatment for that.

Hypothyroidism has no cure, but in almost all cases medication can handle this, bringing the thyroid hormones to a healthy level.

Evidence suggests that there are other ways people can support their thyroid hormone levels, for example with:


Older search from 2015 evaluated the effect of a regular exercise program in 20 people receiving treatment for hypothyroidism. The authors performed blood tests for thyroid hormones before and after 3 months of hour-long daily exercise sessions.

After comparing the results with people who did no physical activity, they concluded that exercise can improve thyroid function.


Iodine is a nutrient that the thyroid gland uses to make thyroid hormones. Most people in the United States get enough iodine.

However, in Rare cases, having an iodine deficiency can cause hypothyroidism. People with iodine deficiency can get more of this substance from foods such as seaweed or from supplements.

If iodine deficiency is not the cause, taking iodine supplements will not provide any benefit.

Additionally, people with an autoimmune thyroid disease, such as Hashimoto’s disease, may find that iodine in foods or supplements makes their condition worse. A doctor or dietitian can advise you on the best approach for each individual.

Something almost everyone can benefit from is a diet that reduces inflammation. According to US Department of Veterans Affairs, inflammation is linked to a number of chronic diseases, including autoimmune thyroiditis. Thyroiditis can lead to hypothyroidism.

People with autoimmune hypothyroidism may benefit from an anti-inflammatory diet. It involves eating:

  • lots of fresh fruits, vegetables, and whole grains
  • at least 30 grams of fiber per day
  • foods that contain omega-3 fatty acids, such as wild salmon
  • monounsaturated or “healthy” fats, such as olive oil, rather than saturated fats

Melatonin is a hormone that the body produces naturally as part of the sleep-wake cycle. Its production increases with evening darkness, promoting healthy sleep, and stops when a person is exposed to light, helping them to wake up.

As a result, it synchronizes the sleep-wake cycle with the rhythm of night and day.

Some people take supplemental melatonin as a sleep aid. According to National Institutes of HealthShort-term use of melatonin supplements appears to be safe, but there is very little research on long-term effects.

A small study from 2001 examined the effect of melatonin on women with hypothyroidism, 36 of whom were perimenopausal and 18 postmenopausal. The researchers randomly sorted the participants into two groups. One group took a placebo at bedtime, while the other took melatonin.

Scientists found that the group taking melatonin had significantly higher levels of thyroid hormones compared to the placebo group after 3-6 months.

They suggested that low melatonin levels due to aging may be linked to low thyroid hormone levels, explaining why taking a melatonin supplement also improved TSH levels.

Large-scale trials are needed to confirm that melatonin is safe and effective for people with hypothyroidism. People who want to try a melatonin supplement should ask a doctor about safe dosages and be aware that the quality of supplements can vary widely.

Many factors may contribute to insomnia, including:

  • stress
  • shift work
  • hormonal changes, such as during pregnancy or menopause
  • lifestyle factors, such as:
    • using electronic devices near bedtime
    • do too little exercise
    • consuming caffeine, nicotine, street drugs, or alcohol
    • take long naps during the day
    • having an irregular sleep schedule
  • environmental factors, such as:
    • noise or light
    • frequent travel to different time zones
    • a temperature that is too hot or too cold in the room

People with sleep disorders may benefit from reducing one of the possible risk factors for insomnia that they can control. For example, it can help:

  • create a cool, dark and comfortable sleeping environment
  • wake up and go to bed at the same time every day
  • reduce or stop caffeine and alcohol consumption
  • stop smoking
  • exercise regularly, but avoid exercising at night before sleeping
  • manage stress or practice relaxation techniques

Hypothyroidism may be linked to insomnia, but research to date is inconsistent.

However, people with hypothyroidism often have trouble tolerating cold temperatures at night or joint and muscle pain that can disrupt sleep. Thyroxine side effects can also lead to trouble sleeping if the dose is too high.

Although thyroid hormone deficiency does not directly cause insomnia, the wide range of symptoms associated with thyroid dysfunction can easily aggravate sleep disturbances and reduce a person’s ability to get restful, quality sleep.

Talk to a doctor if insomnia becomes a persistent problem. Treating the underlying problem and making lifestyle changes to promote sleep can help.