Vitamin D Deficiency
Vitamin D is both an essential fat-soluble vitamin and a hormone your body makes. Its chief role is to help your body absorb calcium and phosphorus and maintain healthy, strong bones, but it has many other roles. Vitamin D is essential for proper nerve, muscle, immune system, brain, and heart function.
Many people don’t get enough vitamin D, leading to a vitamin D deficiency. About 1 billion people worldwide have very low levels, while 50% of the global population has low levels.¹ In the United States, nearly 1 in 4 people have levels too low to maintain healthy bones and overall health.²
Vitamin D is essential for proper nerve, muscle, immune system, brain, and heart function. Many people don’t get enough vitamin D, leading to a vitamin D deficiency. With Cue Health, it’s easy to test and get the treatment for vitamin D deficiency.
What is Vitamin D Deficiency?

What is Vitamin D Deficiency?
A vitamin D deficiency is a blood vitamin D level below 12 ng/mL (30 nmol/L). Levels between 12 ng/mL and 20 ng/mL (30-50 nmol/L) are considered insufficient and increase your risk for deficiency and disease.
A long-term deficiency of vitamin D can lead to a loss of bone density, which can contribute to soft, weak, and fragile bones and weak muscles, leading to fractures, osteomalacia and osteoporosis in adults. In children, a lack of vitamin D leads to rickets, which is a condition that causes soft bones and bone deformities.
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Symptoms
Most people with vitamin D deficiency don’t have any symptoms or might have symptoms that resemble other conditions. Low vitamin D symptoms can also vary based on the severity of the deficiency, other health conditions, and other factors.
You might experience:
• Muscle pain
• Bone pain
• Muscle twitching
• Muscle spasms
• Tiredness
• Weakness
• Frequent bone fractures -
Who It Affects
Your body makes vitamin D in your skin from sunlight and then converts it into an active form in your liver and kidneys. You also absorb vitamin D from food in the small intestine of your digestive system. Few foods naturally contain vitamin D, however.
While anyone can have low vitamin D levels, older people are at increased risk. In the United States, 61% of older people have a deficiency.¹ As you age, your skin loses the ability to make vitamin D, and you’re more likely to spend more time inside, leading to less sun exposure. These factors combined increase your risk of deficiency.
People with certain conditions or lifestyle habits are also more likely to be deficient. This includes people who:
• Were breastfed as infants without vitamin D supplements
• Lack sun exposure
• A vegetarian or vegan diet
• Kidney or liver disease
• Have dark skin pigment
• Are obese
• Have had gastric bypass surgery
• Have certain digestive conditions like ulcerative colitis, Crohn’s disease, or celiac disease -
What Treatment Looks Like
Your clinician might recommend different treatment options depending on your vitamin D levels and other factors. Mildly low levels can often be treated with an over-the-counter vitamin D supplement like vitamin D2 (ergocalciferol) and D3 (cholecalciferol). Both forms increase vitamin D in your blood, but D3 might raise it higher and for longer than D2.
Treatment often starts with a high dose for 6 to 8 weeks and then lowers once your levels have improved, though your clinician will decide on the right amount. Your clinician may prescribe an active vitamin D medication called calcitriol or calcidiol for severe deficiency or a deficiency that doesn’t get better. You may need regular tests to monitor your levels while on this medication.
Low vitamin D levels can also cause low calcium levels. Depending on your tests, your clinician might also recommend you get more calcium in your diet or take calcium supplements. In general, getting the recommended daily amount of vitamin D in your diet or through supplements can help you prevent or treat low vitamin D levels.
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How Cue Can Help You Find Relief
Vitamin D deficiency can happen slowly over time and may cause vague symptoms that can be confused with other conditions. However, vitamin D testing is now often part of routine checkups, and vitamin D deficiency can be quickly diagnosed. Treatment is effective and can help improve your blood levels and overall health.
Cue makes it easy to test your vitamin D levels conveniently with our at-home test kits and get treatment delivered with over-the-counter vitamin D3 supplements. If you'd like to learn more about vitamin D deficiency and how it may be affecting you, Cue makes it easy to connect with a healthcare expert on-demand through the Cue Health App. Whether it’s a diagnosis or treatment, we offer easy, fast, and discreet care.

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¹ https://www.ncbi.nlm.nih.gov/books/NBK532266/
² https://ods.od.nih.gov/factsheets/VitaminD-Consumer/