Can Vitamin D Trigger Insomnia

Can Vitamin D Trigger Insomnia? Uncovering the Truth

Multiple research shows that insomnia and poor sleep quality is highly correlated with vitamin D levels. Individuals with low vitamin D levels are more likely to sleep poorly and develop insomnia.

Do you keep tossing left and right or stare at the ceiling for long hours every night before finally falling asleep? 

Perhaps you wake up to use the restroom and find it hard to go back to sleep. These are all symptoms of insomnia: finding it hard to sleep, staying asleep, or returning to sleep if you wake up in the middle of the night. 

But what role does vitamin D or calciferol have to play in all these? 

In this article, we answer the questions you may have regarding vitamin D and sleep. We share the connection between vitamin D and insomnia and also detail the primary causes of insomnia.

Is there a connection between vitamin D and insomnia?

Many researchers have attempted to establish a direct link between vitamin D and chronic insomnia. 

One of the reasons for the increased focus on vitamin D as a potential contributor to sleep disorders is that scientists have found the sunshine vitamin in parts of the brain that regulate sleep. 

This finding suggests that vitamin D plays a prominent role in the body’s sleep-wake cycle and sleep quality. 

Let’s take a closer look at the links below. 

Can low vitamin D cause insomnia?

Various studies conducted across multiple populations, like older adults, individuals undergoing hemodialysis, and children, have shown a substantial association between low serum vitamin D levels and poor sleep quality. 

A study of 3,048 men aged 68 years or older found that participants with lower vitamin D levels (< 20.3 ng/mL) were more likely to sleep for less than five hours than those with higher levels (≥ 40.06 ng/mL). 

The researchers made the same observation for sleep efficiency. Sleep efficiency is how much time you spend sleeping relative to the time spent in bed. 

Another study of a population with hemodialysis observed that participants with “sleep disturbance” had lower vitamin D in their blood versus those without sleep disturbance. 

This association remained significant even after adjusting for other variables. 

Scientists also explored the relationship between vitamin D levels and sleep deprivation in children. 

A study of 39 children with an average age of 6.6 years showed that the vitamin D deficient (< 30 ng/mL) population slept less and had poorer sleep efficiency versus those with normal or sufficient vitamin D levels. 

These studies, and many more like them, show a strong correlation between low vitamin D levels and insomnia symptoms. 

However, they do not prove that vitamin D deficiency is the cause of insomnia. 

That said, there is evidence that treating vitamin D deficiency can significantly improve sleep duration and help restore a person’s 24-hour sleep-wake cycle. 

Case study of treating insomnia with vitamin D supplements

A 35-year-old woman with excessive daytime sleepiness and insomnia, which she had for more than six years, was treated by doctors. 

The woman had no prior disease and wasn’t taking any medication that could induce a sleep disorder. She had no family history of sleep disorders either. 

The doctors noted that the symptoms are synonymous with non-24 h sleep-wake disorder. This term means the woman’s biological clock is not synchronized with the regular 24-hour day cycle. 

The doctors exposed her to both non-pharmacological and pharmacological treatments, which all failed. Some non-pharmacological treatments included light therapy, physical activity, and sleep hygiene. 

The doctors also tried to correct her circadian rhythm with melatonin. Both approaches failed to ease the woman’s sleep problems. 

The doctors then examined the woman’s vitamin levels and thyroid hormones. 

They found that she had insufficient levels of vitamin D (74% less than the lower limit of normal), vitamin B12 (10% less than the lower limit of normal), and folic acid (71% less than the lower limit of normal). 

The woman was subsequently placed on supplementation to correct the vitamin deficiencies. 

After one month of vitamin D intake, her body returned to the regular 24-hour rhythm. At this point, her vitamin D and folic acid levels were above the lower limit of normal. 

She initially struggled to sleep at her preferred bedtime, but after staying awake for a whole day, she was able to get a 7-hour sleep between 11 p.m. and 6 a.m. without any alarm. 

In subsequent interaction with the doctors, she reported a recurrence of symptoms after stopping her vitamin supplementation. The doctors recommended she resume taking vitamin D supplements only. After some weeks, her daytime sleepiness improved, and she could return to work. 

You can achieve similar results by taking vitamin D supplements. Why Not Natural’s Organic Vitamin D3 and K2 with Spirulina Capsules is packed with 10,000 IU of D3 per capsule. It’s free from fillers and is tailored for quick and maximum absorption, helping you reach your vitamin D goals much quicker. 

Can excessive vitamin D cause insomnia?

There is little to no scientific evidence that excessive vitamin D causes insomnia. There’s sparse research that shows a high dosage of vitamin D may reduce melatonin secretion at night. Melatonin is the hormone that helps the body recognize the difference between day and night. 

One of the studies with a population of multiple sclerosis patients found that melatonin secretion reduced, while blood levels of vitamin D increased after three months in the group that received a high daily dosage (4,370 IU) of vitamin D supplementation. 

However, a vital point is that the study participants were in locations with less sunlight exposure, which may have influenced the participants’ perception of day and night. 

What are the causes of insomnia?

Insomnia can be caused by several issues, including: 

Lifestyle causes

Your habits and lifestyle choices can affect how well you sleep and may lead to insomnia. These lifestyle choices include:

Poor diet and eating habits

Consuming too much confectionery, sugar-sweetened drinks, and generally excessive low-quality carbohydrate (like refined sugars) intake has been linked to poorer sleep quality and insomnia symptoms. 

Conversely, food intake rich in fish and vegetables is associated with good sleep quality. It’s also important to note that the meal you have before bed plays a significant role in how quickly you fall asleep and how well you sleep.

Additionally, skipping breakfast and having no clear eating schedule may affect your sleep quality. 

Lack of exercise or physical activity

In a study of almost 8,000 Danish daytime workers, researchers found that workers who engaged in less physical activity had severe sleep problems. 

The scientists concluded: “These data suggest that a vicious circle may exist between poor sleep and reduced leisure-time physical activity.” 

Researchers also studied the correlation between physical activity and insomnia symptoms in the older male population and found that the former negatively correlates with poor sleep quality. 

Many studies have also shown that increased physical activity can help counter insomnia symptoms. One study found that exercising 30 minutes daily can increase sleep duration by 15 minutes on average

Another study that examined 22 controlled trials on the subject matter reached the same conclusion: physical activity improved sleep quality. 

Smoking and caffeine consumption

An assessment of 818 nonsmokers and 189 smokers found that smoking, particularly nightly smoking, increases insomnia severity and also leads to shorter sleep duration. 

A survey of 3,516 adults revealed similar outcomes; “smoking was associated with difficulty initiating sleep and difficulty waking up.” 

Caffeine and alcohol intake also have a similar effect as smoking. Taking coffee or other drinks with the stimulant close to bedtime will disturb your sleep. 

Watching TV or using gadgets in bed

About 90% of studies examining the association between devices in the bedroom and insufficient sleep concluded that kids using devices in bed delays sleep onset and reduces total sleep time. The same observation has been found in adults. 

Big lifestyle changes

Being in a new environment, changing jobs, having a new infant, a new work or study schedule, and much more can alter your sleep pattern and lead to insomnia. Even jet lag, when not managed properly, may interfere with your sleep, especially if you travel a lot.

Psychological causes

According to the National Alliance on Mental Illnesses (NAMI), psychological causes are responsible for about half of all insomnia cases

The chief culprits include psychological stress, anxiety, and depression. The reality is that whichever comes first can lead to the other. Poor sleep can lead to psychological issues and vice versa. 

In terms of stress, both positive and negative news can cause you to be stressed. 

For example, getting pregnant while being positive news to some people may also induce anxiety and stress, which may lead to insomnia. So it’s something worth monitoring.

Physical causes

Perimenopausal and menopausal women are more likely to suffer from insomnia than younger women. Also, as many as 80% of pregnant women experience insomnia at some point in the pregnancy, particularly during the third trimester. 

Medical conditions

Medical conditions like cancer, diabetes, obstructive sleep apnea, acid reflux, infections, injuries, and various kinds of disorders can affect your sleep quality. 

For example, someone with diabetes is likely to urinate more often during the night due to high blood sugar levels, which may force them to wake up and struggle to return to bed. 


The list of medications that can lead to insomnia include:

  • Cold and allergy decongestants
  • Asthma medications
  • Blood pressure medications
  • Diabetes medications
  • Memory medications
  • Mood and anxiety medications
  • Pain medications
  • Prostate medications
  • Stimulants for attention-deficit/hyperactivity disorder (ADHD)
  • Steroids or anti-inflammatory medications

Does vitamin D improve sleep?

Many studies have shown that taking vitamin D supplements improves sleep quality and sleep duration and helps recipients fall asleep faster. 

Researchers gave vitamin D supplements to veterans with chronic pain and low serum levels of the vitamin. 

Veterans with blood levels lower than 20 ng/mL received 50,000 IU of vitamin D weekly, while those with serum levels between 20-29 ng/mL received 1200 IU daily.

After 19 months, the researchers reported that sleep improved relative to the baseline before participants received vitamin D supplements.

Another clinical trial split participants into two groups and administered a 50,000-unit vitamin D supplement to one group every fortnight for eight weeks. The other group received a placebo. 

The data showed that sleep scores reduced significantly in the group that received dietary supplements compared to the group that received the placebo. 

A meta-analysis of previous studies on the subject matter also came to the above conclusion: vitamin D supplementation leads to a significant improvement in sleep quality.

These studies show that vitamin D can help improve sleep quality and reduce other insomnia symptoms.

What are the symptoms of low vitamin D levels?

Your symptoms largely depend on whether you have an insufficient or deficient vitamin D level. 

The Office of Dietary Supplements at the National Institute of Health notes that a level below 30 nmol/L (12 ng/mL) is considered too low, while 50 nmol/L (20 ng/mL) or above is enough for the body’s needs. 

That said, according to Yale, you may show no symptoms of vitamin D deficiency and yet be deficient. It may take a bone fracture or pain for doctors to request a test. 

That’s why it’s vital to be aware of some of these symptoms so you can be more proactive in managing your health. 

Some of these symptoms include: 

Muscle weakness or pain

Vitamin D deficiency may be the primary or joint cause if you’re experiencing muscle weakness or pain. 

Per this journal article, insufficient or deficient vitamin D levels can lead to musculoskeletal pain, falls, diseases affecting the skeletal muscles, and more. 

An examination of 150 patients complaining of musculoskeletal pain found that 93% had vitamin D deficiency, with blood levels ranging from 11.18-12.99 ng/mL. 

Poor sleep hygiene

There’s no need to belabor this symptom since we’ve established a clear association between vitamin D and sleep. So, if you’re struggling with sleep despite having the right conditions and environment for quality sleep, vitamin D deficiency may be the reason.  

Hair loss

Are you shedding hair more than usual? Vitamin D has been found to play an essential role in new follicles creation. Hair follicles help grow your hair. So, less vitamin D equals fewer hair follicles and, thus, less hair. 

A meta-analysis of past research shows that vitamin D is associated with scarring and non-scarring alopecias. Alopecias are conditions or ailments that lead to hair loss. 


Fatigue may be caused by several things, including poor sleep hygiene and quality, poor diet, lack of daily physical activity, and vitamin D deficiency. 

Researchers in Norway examined 572 patients in a cross-sectional descriptive study. These patients complained of fatigue, musculoskeletal pain, and headache and were all tested for vitamin D levels. 

About 58% of the patients had vitamin D levels below 20 ng/ml or 50 nmol/L. This figure was 83% in patients from South Asia, Africa, and the Middle East. 

Research has also shown that vitamin D supplementation can help improve fatigue in healthy populations deficient in calciferol. 

Depression and mood disorders

Do you suddenly flip between moods? One minute, you’re happy, and the next minute, you’re sad and angry. Well, it seems vitamin D may have a role in how you feel. 

This is because scientists found that people with depression had a higher prevalence of vitamin D deficiency than those without. A meta-review of multiple studies also revealed that low vitamin D levels are strongly associated with depression. 

Sixty-four percent of 14 studies in another meta-analysis showed a strong negative correlation between postpartum depression and vitamin D deficiency. 

Rickets in children and osteomalacia in adults

At this point, it’s no longer a symptom but a full-blown disease due to prolonged vitamin D deficiency, which inhibits bone mineralization. 

Both conditions refer to a scenario where your bone is soft enough to bend and easily break. It’s called rickets in children and osteomalacia. 

Exclusively breastfed babies are at a high risk of rickets because breast milk contains small amounts of vitamin D. 

The American Academy of Pediatrics recommends that parents give infants 400 IU of vitamin D daily to provide the required amount of nutrients needed for strong and healthy bones. 

Do you have a newborn or an infant? Are they on exclusive breastfeeding? 

Help them avoid rickets and get the daily required amount of vitamin D with Vitamin D3 liquid drops supplement fortified with vitamin K2 by Why Not Natural. 

Other symptoms of vitamin D deficiency

Other symptoms of vitamin D deficiency include:

  • Osteopenia or osteoporosis
  • Poor wound healing
  • Loss of appetite
  • Regular recurring illness or infections
  • Pale skin
  • Weight gain
  • Anxiety

How to increase your vitamin D Levels and improve sleep

There are three approaches to increasing your vitamin D levels. You can increase your daily sun exposure, eat vitamin D-rich foods, or take vitamin D supplements. We’ll explore these three methods below. 

Daily sun exposure

The sun hitting your skin aids vitamin D production, and the best time to go under the sun is around noon. Sadly, many people do not get enough daily sun exposure to reach the needed vitamin D level. 

And even when they do, other factors like time of the day, skin color, and what a person wears can influence how much vitamin D your body produces from the sun. 

Melanin limits the body's ability to produce vitamin D from the sun. That's why African Americans have the highest prevalence of Vitamin D deficiency and insufficiency. 

Those with darker skin must spend more time under the sun to produce the same amount of vitamin D as the non-Hispanic white population. 

Your location also plays a notable role in how much vitamin D your body can generate from the sun. 

A study found that someone in Miami will need to spend only three minutes under the sun at noon to produce the vitamin D the body needs, while someone in Boston will need to spend twenty more minutes. 

Vitamin D-rich foods

Foods rich in vitamin D include fatty fish like tuna and mackerel, some cheese, egg yolks, and mushrooms. 

As you can see, your options are not that great or limitless. That’s why many products like milk and cereal are fortified with vitamin D to fill this nutrient gap. 

Notwithstanding, many people struggle to eat at all, talk more of eating a balanced diet. 

Vitamin D supplements

Taking vitamin D supplements is the fastest and most reliable way to increase your vitamin D levels. 

It simply removes the roadblocks associated with the other two methods discussed above. 

If you’re considering vitamin D supplements, vitamin D3 is the recommended variant for dealing with deficiency or insufficiency. Per many sources, vitamin D3 is more active and thus more effective

If you’re deficient, you’ll need a loading dose upfront. This dosage is typically between 25,000-50,000 IU, which you’ll take once weekly for two to three months. 

You’ll only require a maintenance dose of 800-10,000 IU when your vitamin blood levels have returned to normal, depending on your specific case.  

Our Organic Vitamin D3 and K2 With Spirulina Capsules contain 10,000 IU of D3 per capsule to boost and maintain your vitamin D levels. 

Health benefits of taking vitamin D

Vitamin D has many benefits, including the following:

Muscle strength and healthy bones

Bones need calcium and phosphorus to form and retain their structure and strength. However, the body cannot absorb calcium without the help of vitamin D. 

Vitamin D also regulates calcium concentration in the blood, ensuring you’re not at risk of hypercalcemia or toxic calcium levels in the blood. 

Adequate and optimal vitamin D keeps your bones and muscles strong and prevents conditions like osteomalacia, rickets, and osteoporosis. 

Reduced risk of dying from cancer

Researchers found that there was a higher rate of colon cancer deaths in places where natural light is limited. The hypothesis here is that less natural light equates to lower vitamin D levels. 

Three separate studies also found that taking vitamin D supplements can reduce cancer mortality rates by at least 12%. However, vitamin D supplementation does not prevent cancer. 

Prevent seasonal flu and cold

Seasonal flu and cold leads to less productivity. Research has shown that taking vitamin D can help during flu season. 

Of 340 students, 170 were put on a daily dose of 1,200 IU of vitamin D, while the other half received a placebo. Only 10.8% of the vitamin D group experienced flu, while 18.6% of the placebo group did. 

The difference was even more pronounced (2 in the vitamin D group versus 18 in the placebo group) in students with a history of asthma. 

Promotes a healthy heart

Do you want to build a stronger and healthier heart? Take vitamin D! 

A study of over 18,000 men found that the group with higher vitamin D levels (at least 30 ng/mL) was significantly less likely to develop a heart attack than those with lower levels (less than ≤15 ng/mL). 

Maintain cognitive ability in old age

Scientists measured the amount of vitamin D in four brain regions of 290 participants from the Rush Memory and Aging Project. 

The results show that participants with a higher concentration of vitamin D in the brain were significantly less likely to suffer dementia or cognitive decline by as much as 33%.  

Numerous other studies also reach similar conclusions. One in particular found that those with vitamin D levels below 25 nmol/L were at more risk of developing dementia. 

Promotes healthy mood and good sleep

Researchers found that having adequate levels of vitamin D helps the body to produce serotonin, a key neurotransmitter with multiple functions, including regulating mood and cognition. 

Low serotonin has been complicated in many mental disorders, including mood disorders, anxiety disorders, major depressive disorder, and more. 

May help with your weight loss journey

Half of 50 obese or overweight women were given 50,000 IU of vitamin D weekly for six weeks. The other half received a placebo. 

The women in the vitamin D group had a notably lower body mass index, weight, and waist circumference than the placebo group at the end of the study. 

May help prevent type 2 diabetes

According to the American Diabetes Association, low vitamin D levels increase the risk of insulin resistance

Insulin insurance prevents the body from using insulin to control your blood sugar, which can lead to diabetes. 

A study found that optimal vitamin D can reduce the risk of type 2 diabetes by 13%. 

Boosts oral health

You’re more likely to develop dental caries with lower levels of vitamin D. According to a study, your risk is at 2.48 times higher compared to someone with normal vitamin levels. 

Another study established a clear association between periodontitis and low calciferol. 

Prevents acne

A meta-analysis of previous research found that patients with higher levels of vitamin D had less severe acne versus those with deficient or insufficient levels. 

Another study found that vitamin D supplements improved the patients’ inflammatory lesions

Read also: Discover 11 Incredible Ways Vitamin D Aids Your Body

How long will it take for vitamin D supplements to work?

How long vitamin D will take to work depends on your vitamin D baseline, dose, consistency, age, if you get extra from the sun or food, and prior medical conditions. Vitamin D-deficient individuals may need at least three months for their blood levels to return to normal. 

One study found that retesting after four weeks of dietary supplementation showed no notable increase in vitamin D levels.

However, testing after 3-9 months showed the most significant increase

Two persons may take the same dose of vitamin D and end up with different results. 

Certain prior conditions like obesity may limit the absorption of vitamin D, while skin color may also reduce how much vitamin D your body can synthesize from the sun.

The consensus is that daily vitamin D supplementation of at least 2,000 IU will likely take months for your blood levels to return to normal. 

But you may begin to experience a difference from about a few weeks as your numbers improve. 

Can vitamin D supplements be taken without consulting a doctor?

You can take moderate doses of vitamin D without consulting a doctor if you’re a certified healthy person. However, the goal of taking vitamin D or any dietary supplement shouldn’t be to treat any sickness or disease but to boost and maintain your blood levels. 

Supplements are generally safe to consume. The United States Food and Drug Administration (FDA) has many mechanisms like the Good Manufacturing Practices (GMPs) in place to ensure supplements are as advertised. 

More importantly, it’s imperative to stay within the stipulated daily intake level. 

For vitamin D, this study notes that the “safe upper intake level for vitamin D3 is 10,000 IU daily.”

Consult your doctor before purchasing any drug or dietary supplements if you have any disease or ailment or you’re taking prescribed medication. 

Also, keep a record of the supplements you take and their doses to help your doctor in case you experience any adverse effects.

What should I take with vitamin D supplements?

For the most part, you can take vitamin D with other dietary supplements. However, research shows that taking magnesium alongside may be helpful. 

Per this study, magnesium level was inversely associated with vitamin D insufficiency.  

Can vitamin D be taken with other supplements?

You can take Vitamin D with other supplements. The supplements you choose to take with vitamin D will depend on your goal. For example, if you want to sleep well, combine it with melatonin at night. 

Can vitamin D be taken with multivitamins?

You may need to wait some hours before taking multivitamins if you’re taking vitamin D with magnesium. This is because magnesium reduces the absorption rate of zinc and calcium. 

Otherwise, there are no harmful interactions to expect when you take vitamin D with multivitamins. 

Can vitamin D be taken with Omega 3?

There’s no conflict when you take vitamin D with Omega 3. They do not counteract each other nor reduce the absorption rate of the other.  

Can vitamin D be taken with vitamin C?

You’ll see vitamins C and D together in many multivitamins if you check the factsheet. They’re both great for your immune system. You should, however, consult your doctor if you’re at risk of kidney stones. 

Boost your immune system and prevent urinary tract infections with our 5-in-1 supplement with Vitamins C and D, made with natural ingredients and suitable for both men and women.

Should I take vitamin D daily or once a week?

Most doctors recommend taking a smaller dose of vitamin D daily if the goal is to maintain an already normal vitamin D level. 

However, they may prescribe a larger weekly dose of at least 25,000 IU if you’re vitamin D deficient. This dose will probably last a few weeks (8-12) before you return to a lower daily dosage. 

Should I take vitamin D at night or in the morning?

You can use your vitamin D supplements during the daytime or at night. Our stance at Why Not Natural is to maintain a consistent schedule so that your dietary supplement is part of your daily routine. 

Who should avoid taking vitamin D supplements?

You may want to avoid vitamin D supplementation if you already have high calcium in your bloodstream. 

People with celiac disease should avoid the supplement, too, as the disease causes malabsorption issues. Also, individuals taking drugs for lowering cholesterol or thiazide diuretics should equally abstain from vitamin D. 

What are the symptoms of excessive vitamin D?

Excess calciferol in the body is also known as vitamin D toxicity or hypervitaminosis D. 

The primary symptom of this condition is elevated calcium levels in the blood, which may lead to high blood pressure and developing kidney stones.

The symptoms of excessive vitamin D include:

  • Hypercalcemia or elevated calcium levels come with symptoms like confusion, nausea, vomiting, loss of appetite, frequent urination, dehydration, muscle weakness, heart attack, and an injured kidney. 
  • Gastrointestinal symptoms like constipation, diarrhea, and stomach pain. 
  • Bone pain
  • Kidney problem
  • Increased thirst
  • Fatigue and lethargy

To avoid vitamin D toxicity, it’s imperative to stick to less than 10,000 IU daily and avoid the supplement if you have the risk factors shared earlier in the article. 

The Food and Nutrition Board (FNB) says that it’s very unlikely that you’ll develop vitamin D toxicity with a daily intake below 250 mcg or 10,000 IU.

Takeaway: Get more restful and quality sleep with vitamin D

We explored the relationship between vitamin D and insomnia and showed that the former is strongly associated with the latter. 

We also shared a case study of how a woman with excessive daytime sleepiness got better through vitamin D supplementation. 

The bottom line is that optimal vitamin D works wonders for quality sleep. You’ll fall asleep quicker, sleep longer, and feel more restful when you wake.

Visit the Why Not Natural supplement store today to check out our vitamin D supplement and other range of dietary supplements. 

Our products contain only quality and natural ingredients and are vegan-friendly. 

More importantly, we engineered them for quick absorption so you can reap the rewards sooner.

Don't forget to subscribe to our newsletter to learn which supplements to take, how to combine them for maximum benefit, and other health tips to boost your energy and vitality. Plus, discover natural strategies to reduce hormonal imbalances, stress, and anxiety. Click here to get started!

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