Vitamin D Deficiency: What are the symptoms?
Vitamin D deficiency symptoms can vary from subtle to severe and often develop gradually. Early signs include fatigue, bone or back pain, muscle weakness or cramps, frequent illness, and hair loss. If untreated, deficiency may result in serious conditions such as osteoporosis, rickets, and difficulty with movement.
Early Symptoms of Vitamin D Deficiency
Even in its early stages, vitamin D deficiency can cause noticeable changes in how you feel and function. These initial signs are often subtle and can be mistaken for everyday fatigue or minor health issues, but recognizing them early can help prevent more serious complications. Here are several symptoms of having low vitamin D levels:
- Fatigue or tiredness
- Bone pain or back pain
- Muscle weakness or cramps
- Frequent infections
- Hair loss
- Slow wound healing
- Low mood or depression
Advanced or Severe Symptoms
While early signs of vitamin D deficiency may be easy to overlook, more advanced symptoms can lead to serious health problems. These severe effects develop over time and signal a greater impact on your bones, muscles, and ability to move, highlighting the importance of early detection and intervention.
- Osteoporosis or bone fractures
- Rickets (in children)
- Osteomalacia (in adults)
- Severe muscle weakness
- Difficulty walking or climbing stairs
Detailed Symptom Explanations
Fatigue or Tiredness
Vitamin D is vital to energy metabolism. Low levels can leave you feeling constantly tired or lacking in energy, as vitamin D participates in mitochondrial function and hormonal regulation that impact fatigue. Multiple studies link deficiency with increased fatigue and poor sleep quality.
Bone Pain or Back Pain
Vitamin D helps the body absorb calcium, a key mineral for bone strength. Deficiency disrupts calcium absorption, weakening bones and causing persistent pain, commonly in the lower back or joints.
Muscle Weakness or Cramps
The vitamin influences muscle fibers—deficiency can lead to generalized muscle weakness, increased cramps, and difficulty with normal movements like climbing stairs. Severe cases may impair mobility altogether.
Frequent Infections
Vitamin D modulates the immune system. Low levels may increase vulnerability to infections, especially respiratory illnesses and slow recovery from illness due to weaker immune defenses.
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Hair Loss
Research shows a link between vitamin D deficiency and certain hair loss disorders, such as alopecia areata, possibly due to the vitamin’s role in hair follicle cycling.
Slow Wound Healing
Vitamin D helps regulate cellular growth and tissue repair. Deficiency can delay wound healing after injury or surgery, as inadequate levels may impair new tissue formation.
Low Mood or Depression
Evidence connects vitamin D to hormone and neurotransmitter regulation. Deficiency can contribute to low mood, depression, and anxiety, although this relationship is complex and still being studied.
Osteoporosis / Fractures
Long-term deficiency reduces bone density, raising the risk of osteoporosis and fractures, particularly in older adults.
Rickets / Osteomalacia
Rickets occurs in children and leads to soft, weak bones and skeletal deformities (such as bowed legs). Adults may develop osteomalacia, which causes diffuse bone pain and tenderness due to poor mineralization.
What Causes Vitamin D Deficiency?
Vitamin D deficiency can result from insufficient dietary intake, limited sun exposure, dark skin pigmentation, malabsorption disorders, kidney/liver disease, or medications that interfere with vitamin D metabolism. At-risk groups include older adults, breastfed infants, people with chronic illnesses, and those who stay indoors or avoid sunlight.
When to See a Doctor
You should see a doctor if you experience persistent fatigue, bone or muscle pain, frequent infections, or hair loss. Certain groups—older adults, breastfed infants, people with darker skin, and those with digestive disorders—are at higher risk. Since symptoms overlap with other conditions like depression and fibromyalgia, a blood test can determine your vitamin D levels and guide treatment.
If you suspect vitamin D deficiency, or belong to an at-risk group and experience related symptoms, consult your healthcare provider for assessment and possible blood testing. Early diagnosis and management can help prevent long-term health complications.
References
- Akpınar, Ş., & Karadağ, M. G. (2022). Is Vitamin D Important in Anxiety or Depression? What Is the Truth?. Current nutrition reports, 11(4), 675–681. https://doi.org/10.1007/s13668-022-00441-0
- Bordelon, P., Ghetu, M. V., & Langan, R. (2009). Recognition and management of vitamin D deficiency. American Family Physician, 80(8), 841–846. https://www.aafp.org/pubs/afp/issues/2009/1015/p841.html
- Kaur, J., et. al. Vitamin D Deficiency. [Updated 2025 Feb 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Accessed on August 11, 2025 at https://www.ncbi.nlm.nih.gov/books/NBK532266/
- National Library of Medicine. (2024, April 22). Vitamin D Deficiency. MedlinePlus. Retrieved August 12, 2025, from https://medlineplus.gov/vitaminddeficiency.html
- Saini, K., & Mysore, V. (2021). Role of vitamin D in hair loss: A short review. Journal of cosmetic dermatology, 20(11), 3407–3414. https://doi.org/10.1111/jocd.14421
- Siregar, F. D., & Hidayat, W. (2023). The Role of Vitamin D on the Wound Healing Process: A Case Series. International medical case reports journal, 16, 227–232. https://doi.org/10.2147/IMCRJ.S402005
- Smith, K., & Hewlings, S. (2020). Correlation between vitamin D levels and hard-to-heal wounds: a systematic review. Journal of wound care, 29(Sup7), S24–S30. https://doi.org/10.12968/jowc.2020.29.Sup7.S24
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How long does it take for vitamin D to work?
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How can I raise my vitamin D levels quickly?
You can raise your vitamin D levels quickly in three main ways, but it can take up to a week for increased vitamin D intake or exposure to be reflected in a vitamin D blood test: increasing your intake of foods that are naturally rich in vitamin D or fortified with vitamin D, taking a vitamin D supplement, or getting outside and exposing your skin to sunlight (although experts do not recommend this without sun protection). Continue reading
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