Vitamin D deficiency
Last updated: 5 Nov. 2025
Reviewed by: Specialist doctors from the Elfcare quality team
Feeling low on energy, catching colds more often, or noticing muscle aches? These subtle signs might point to something deeper, like low vitamin D. Many adults live with mild vitamin D deficiency without knowing it. The symptoms are vague, but the impact is real.
Vitamin D plays a key role in bone strength, immune support, and mood regulation. When levels drop, your body starts sending quiet signals. The good news is that you can detect imbalances early through a simple blood test.
Book your consultation now to test your vitamin D levels
What is vitamin D deficiency?
Vitamin D is a fat-soluble vitamin your body makes when exposed to sunlight. It also comes from certain foods like fatty fish, eggs, and fortified dairy.
Once in your system, vitamin D helps regulate calcium and phosphate. These minerals are essential for strong bones, muscle function, and immune health. Vitamin D also supports mood and energy by interacting with brain and hormone pathways.
When levels are too low, your body struggles to absorb calcium properly. This can lead to bone pain, fatigue, and a weakened immune response. Too much vitamin D is rare, but low levels are common, especially in northern climates or among people who spend most of their time indoors
Symptoms of vitamin D deficiency
Vitamin D deficiency symptoms can be subtle.
Here are common signs to watch for:
Fatigue or low energy
Muscle weakness or cramps
Bone or back pain
Frequent colds or infections
Mood changes like low mood or irritability
Hair thinning or loss
Slow wound healing
Less common signs may include:
Joint stiffness
Weight gain
Difficulty concentrating.
Symptoms often overlap with other conditions. That’s why testing is so important. It brings clarity.
What causes vitamin D deficiency?
Several factors can lead to low vitamin D levels:
Limited sun exposure, especially in winter or for those with indoor lifestyles
Darker skin tone, which reduces vitamin D production
Ageing, as older adults produce less vitamin D naturally
Diet low in vitamin D, especially in plant-based diets
Certain medications like steroids or anticonvulsants
Digestive conditions that affect absorption, such as celiac or Crohn’s disease
Risk factors vary, but lifestyle and geography play a big role.
How is vitamin D deficiency detected?
A blood test for vitamin D measures your 25-hydroxyvitamin D (25(OH)D) level. This is the best indicator of your body’s vitamin D status.
25(OH)D shows how much usable vitamin D is circulating in your blood
Levels below 30 ng/mL may indicate deficiency
Results are interpreted alongside calcium, phosphate, and parathyroid hormone (PTH) levels for a full picture
Elfcare’s blood tests measure 25(OH)D and related markers so you can spot imbalances before they start affecting your daily life.
Why early detection matters
Vitamin D deficiency develops slowly. You may feel fine for months until fatigue, aches, or low mood become routine.
Early insight allows small, simple steps. You can adjust your diet, spend more time outdoors, or follow up with your doctor. You’ll feel more energized, focused, and resilient.
It’s not about treating illness. It’s about maintaining balance and supporting long-term health.
How Elfcare can help
Elfcare’s preventive health checks include key biomarkers for vitamin D status. We focus on awareness, not diagnosis, so you can understand your results and take action early.
Our platform helps you track changes over time, discuss results with your provider, and make informed lifestyle choices.
Summary
Vitamin D deficiency is common, often silent, and easy to miss. But with regular testing, you can catch it early before symptoms affect your energy, mood, or immune health.
When you understand your body, you can make choices that support your energy, focus, and long-term health.
Last updated: 5 Nov. 2025
Reviewed by: Specialist doctors from the quality team at Elfcare
FAQs
Vitamin D deficiency means your body doesn’t have enough vitamin D to support bone strength, muscle function, and immune health. It’s common in people who get little sunlight or have limited intake of vitamin D–rich foods. Fatigue, low mood, and muscle weakness are early signs that often go unnoticed until a blood test confirms low levels.
What is vitamin D deficiency?
The most common symptoms include tiredness, low mood, muscle or joint pain, reduced strength, and increased susceptibility to colds or infections. In the long term, severe deficiency can contribute to bone loss and osteoporosis.
What are common symptoms of vitamin D deficiency?
How is vitamin D deficiency diagnosed?
A simple blood test measuring 25-hydroxyvitamin D (25(OH)D) shows whether your levels are within a healthy range. This test helps identify mild, moderate, or severe deficiency so that treatment can be adjusted accordingly.
Can vitamin D deficiency be treated or improved?
Yes. Most people can restore healthy levels through vitamin D supplements, dietary changes, and safe sun exposure. In more severe cases, a doctor may recommend higher-dose supplements for a limited period. With the right approach, symptoms often improve within weeks.