Written by the Nuvirox Research Team
Key Points
- A systematic review found hyperthyroidism is consistently linked to insomnia, while the hypothyroidism link is weaker and more inconsistent than commonly assumed.
- A study of 137 Graves' disease patients found 66.4% had difficulty falling asleep.
- A study of older men (MrOS study) found neither subclinical hypothyroidism nor hyperthyroidism was significantly associated with decreased sleep quality.
Short answer: an overactive thyroid has a clear, consistent link to insomnia; an underactive thyroid's connection to insomnia is real but considerably weaker and more inconsistent than a lot of health content implies.
See a Doctor Before Self-Treating
This article covers general research on thyroid function and sleep. If you have a diagnosed or suspected thyroid condition, please work with your doctor or endocrinologist on both the thyroid diagnosis and any related sleep symptoms — thyroid hormone levels require blood testing to assess properly, and self-treating suspected thyroid-related insomnia without medical guidance isn't advisable.
Does an overactive thyroid actually cause insomnia?
The evidence here is fairly consistent. A study of 137 patients with Graves' disease — the most common cause of hyperthyroidism — found 66.4% reported difficulty falling asleep. A systematic review on thyroid dysfunction and sleep describes hyperthyroidism as heightening neural excitability due to thyrotoxicosis, which is considered the primary driver of insomnia in these patients, alongside nervousness and irritability that can cause arousal and make falling asleep harder. Hyperthyroidism has also been specifically linked to restless legs syndrome in review literature, adding another potential sleep-disrupting factor beyond insomnia alone — a connection worth knowing about alongside the general pattern described in why your legs feel weird at night.
What about an underactive thyroid — does that cause insomnia too?
This is the part where the evidence is genuinely weaker than commonly assumed, and worth stating plainly rather than glossing over. A systematic review on thyroid function and sleep patterns notes that in one study, patients with hypothyroidism had longer sleep latency, shorter sleep duration, and lower sleep satisfaction than euthyroid individuals — but a different study found no relationship between subclinical hypothyroidism and sleep quality at all. The Osteoporotic Fractures in Men (MrOS) study, using both objective actigraphy and subjective sleep measures in 682 older men with thyroid function data, found that neither subclinical hypothyroidism nor subclinical hyperthyroidism was significantly associated with decreased sleep quality — directly contradicting the assumption that any thyroid abnormality reliably disrupts sleep.
A 2024 Mendelian randomization study, which uses genetic data to test for causal relationships, found no bidirectional causal link between insomnia and hyperthyroidism, hypothyroidism, thyroiditis, or thyroid nodules — though it did find that thyroid cancer specifically increased the risk of insomnia. This kind of genetic evidence suggests that many of the associations seen in observational studies may reflect overlapping symptoms or shared risk factors rather than one condition directly causing the other.
So why do so many articles say hypothyroidism definitely causes insomnia?
Likely because the symptom overlap is genuinely confusing to disentangle. A systematic review notes that individuals with hypothyroidism experiencing symptoms like muscle and joint pain, cold intolerance, or anxious mental states may have insomnia driven by those symptoms rather than by low thyroid hormone directly — and untangling "hypothyroidism causes insomnia" from "hypothyroidism causes symptoms that happen to also disrupt sleep" is difficult with the observational data available. The same review also notes obstructive sleep apnea and restless leg syndrome are both more common in people with thyroid dysfunction, adding further overlapping conditions that could explain some of the observed association without a direct hormonal mechanism — which is also why unexplained sleep symptoms alongside cold feet at night are worth a thyroid panel rather than guesswork.
An important interaction to know about before considering ashwagandha for sleep
Ashwagandha, an ingredient in many sleep-support blends (including this one), has been studied for its effects on thyroid hormone levels, and some research has found it can increase T4 (thyroxine) levels. That's occasionally explored as a potential benefit for people with underactive thyroid, but it also means it isn't a neutral ingredient if you're managing a thyroid condition, especially hyperthyroidism, or taking thyroid medication where hormone levels need to stay within a specific target range. If you have any thyroid condition or take thyroid medication, please talk with your doctor or endocrinologist before adding an ashwagandha-containing supplement, so your thyroid levels can be monitored appropriately.
Is there a deeper biological reason thyroid hormone and sleep are connected at all?
Yes — thyroid-stimulating hormone (TSH) itself follows a circadian rhythm, and research on the hypothalamus-pituitary-thyroid (HPT) axis describes it as both influenced by and influencing sleep quality and duration, rather than sitting in a one-way relationship. Clinical research has found that intravenously administered thyrotropin-releasing hormone (TRH) can alter sleep parameters directly, including reduced non-REM sleep and changes in sleep efficiency or wakefulness, which is direct physiological evidence that this axis has real effects on sleep architecture, not just a statistical association in survey data. Related research on the hypothalamus-pituitary-gonadal (HPG) axis found that postmenopausal women with lower estradiol and higher luteinizing hormone had poorer sleep quality, including less deep sleep, suggesting insomnia in midlife may sometimes reflect an overlapping set of hormonal-axis changes rather than the thyroid acting in isolation — one more reason a full hormone picture, not just a single thyroid panel, can be useful context for a doctor evaluating unexplained sleep problems.
Frequently asked questions
Is insomnia a reliable sign of a thyroid problem?
For hyperthyroidism, difficulty sleeping is a fairly consistently reported symptom in the research (like the 66.4% rate in the Graves' disease study). For hypothyroidism, the evidence is considerably more mixed, with some well-designed studies finding no significant link at all — so insomnia alone isn't a reliable stand-in for a thyroid diagnosis either way.
If I have hypothyroidism, will treating it fix my sleep?
This isn't clearly established in the research — some of the sleep problems in hypothyroidism may stem from overlapping symptoms like joint pain or anxiety rather than the low thyroid hormone level itself, so results may vary and this is worth discussing with your treating doctor.
Can I take a sleep supplement with ashwagandha if I have a thyroid condition?
Please check with your doctor or endocrinologist first — ashwagandha has been found in research to affect thyroid hormone (T4) levels, which matters especially if you're on thyroid medication or being monitored for a thyroid condition.
From Nuvirox
Why we formulated Sleep+ Restore
Sleep+ Restore pairs 10 mg of melatonin with a 905 mg blend of calming botanicals and amino acids — L-tryptophan, L-theanine, chamomile, passionflower, ashwagandha, GABA, and 5-HTP among others — studied individually for supporting relaxation and sleep onset. It is backed by a 60-day money-back guarantee, long enough to actually evaluate it the way sleep research suggests you should.
Because Sleep+ Restore contains ashwagandha, which has been shown in research to affect thyroid hormone levels, please talk to your doctor or endocrinologist before using it if you have any thyroid condition or take thyroid medication.
The bottom line
The connection between thyroid problems and insomnia is real for hyperthyroidism, with fairly consistent research support, but considerably weaker and more inconsistent for hypothyroidism than most general health content suggests — a well-designed study of older men found no significant link at all for either subclinical condition. If you have a thyroid condition, loop in your doctor before adding any new supplement, particularly given ashwagandha's documented effect on thyroid hormone levels.
References
- Thyroid Function and Sleep Patterns: A Systematic Review. PMC11285688.
- Song ML, et al., as cited in: Thyroid Dysfunction and Sleep Disorders. PMC8423342.
- Kim EJ, et al. Association Between Thyroid Function and Objective and Subjective Sleep Quality in Older Men: The Osteoporotic Fractures in Men (MrOS) Study. PMC4363141.
- The interplay between subclinical hypothyroidism and poor sleep quality: A systematic review. Sleep Med. 2024. ScienceDirect S0953620524001171.
- Alterations in Hypothalamus-Pituitary-Adrenal/Thyroid Axes and Gonadotropin-Releasing Hormone in the Patients with Primary Insomnia: A Clinical Research. PMC3739817.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.