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Vitamins

Vitamin D (25-OH)

Vitamin D is a fundamental marker for preventive health, supporting bone strength, immune defence, and overall well-being. Regular monitoring helps you stay ahead of potential deficiencies.

Doctor's Assessment Included

When is this value abnormal?

See the value that applies to you:

Choose male or female — this range differs by sex.

Enter your age — this range changes with age.

This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

up to 69 years Your group

Decision limits per result, in nmol/l
Result Value (nmol/l)
Deficiency < 30
Sufficient ≥ 30

70 years and older Your group

Decision limits per result, in nmol/l
Result Value (nmol/l)
Severe deficiency < 35
Deficiency 35–50
Sufficient ≥ 50

Nederlandse richtlijnen zijn het niet eens over deze grens. Het Zorginstituut stelt vast: "Er ontbreekt een eenduidige grens voor vitamine D-deficiëntie" (2022). Wij volgen de Gezondheidsraad, het NHG en het Farmacotherapeutisch Kompas. De NVKC hanteert 50 nmol/l voor iedereen; de osteoporoserichtlijn hanteert 50 nmol/l bij verhoogd fractuurrisico.

Source: Gezondheidsraad Reference population: Nederlandse bevolking (Gezondheidsraad 2012)

Source: Zorginstituut Nederland Reference population: Nederlandse bevolking (Gezondheidsraad 2012)

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

What It Measures

This test measures the level of 25-hydroxyvitamin D in your blood, which is the main circulating form of vitamin D and the most reliable indicator of your overall vitamin D status.

Why It Matters

Adequate vitamin D levels are essential for strong bones, a well-functioning immune system, and overall well-being. Low levels may be associated with an increased risk of bone disorders, mood changes, and weakened immunity. Consult your healthcare provider for personalised advice.

When to Test

Testing may be recommended if you experience fatigue, bone pain, or muscle weakness, or if you have limited sun exposure. Seasonal testing in autumn or winter can be helpful, as vitamin D production from sunlight is reduced during these months.

Symptoms

Low Levels

Symptoms of low vitamin D may include fatigue, bone pain, muscle weakness, frequent infections, and mood changes such as feelings of low mood. In severe cases, it may be associated with bone softening or increased fracture risk.

High Levels

Excessively high vitamin D levels, usually from over-supplementation, may cause nausea, vomiting, weakness, and excessive calcium build-up, which can affect kidney function. Consult your healthcare provider if you suspect elevated levels.

Recommendations

Male

If Low

Low vitamin D may cause fatigue, muscle weakness, and bone pain. Consider 2000-5000 IU daily supplementation and increase sun exposure.

If High

High vitamin D may indicate excessive supplementation. Reduce supplement dose and retest in 3 months.

Female

If Low

Low vitamin D may cause fatigue, muscle weakness, and bone pain. Consider 2000-5000 IU daily supplementation and increase sun exposure.

If High

High vitamin D may indicate excessive supplementation. Reduce supplement dose and retest in 3 months.

Lifestyle Tips

Aim for regular, safe sun exposure of around 15–20 minutes daily when possible. Include vitamin D-rich foods such as fatty fish, egg yolks, and fortified dairy products. Consider supplementation during winter months after consulting your healthcare provider.

Frequently Asked Questions

How much sunlight do I need for vitamin D?
Around 15–20 minutes of midday sun exposure on face and arms may be sufficient for many people, but individual needs vary based on skin tone, location, and season. Consult your healthcare provider for personalised guidance.
Can I get enough vitamin D from food alone?
It can be challenging to obtain sufficient vitamin D from food alone, as few foods are naturally rich in it. Fatty fish, fortified foods, and egg yolks are good sources, but supplementation may be needed, especially during winter.
What is a healthy vitamin D level?
Optimal ranges may vary depending on the laboratory and guidelines used. Your healthcare provider can help interpret your results in the context of your overall health and lifestyle.

Test Products

This marker is included in the following test panels.

Whoop

A 44-biomarker comprehensive health panel inspired by WHOOP Advanced Labs — a deep look at metabolism, cardiovascular risk, hormones, liver, kidney and inflammation.

SHBG (Sex Hormone Binding Globulin) TSH (Thyroid Stimulating Hormone) ALT (Alanine Aminotransferase) LDL Cholesterol Cortisol DHEA-S Estradiol (E2) Free Testosterone FSH (Follicle Stimulating Hormone) LH (Luteinizing Hormone) Total Testosterone Bicarbonate Calcium Chloride Ferritin Iron (Serum) Magnesium Potassium Sodium Transferrin CRP (C-Reactive Protein) Homocysteine Glucose (Fasting) HbA1c (Glycated Hemoglobin) ApoB (Apolipoprotein B) HDL Cholesterol Omega-3 Index Total Cholesterol Albumin HOMA-IR ALP (Alkaline Phosphatase) AST (Aspartate Aminotransferase) Bilirubin (Total) Total Protein Urea (BUN) Creatinine Vitamin D (25-OH) eGFR (Estimated Glomerular Filtration Rate) Insulin (Fasting) Leukocyte Differential Transferrin Saturation Lipoprotein(a) Triglycerides Basic Blood Count
€499,-

InsideTracker

A 36-biomarker performance and longevity panel inspired by InsideTracker Ultimate — covering heart, hormones, metabolism, inflammation, recovery and iron status.

SHBG (Sex Hormone Binding Globulin) TSH (Thyroid Stimulating Hormone) ALT (Alanine Aminotransferase) LDL Cholesterol GGT (Gamma-Glutamyl Transferase) Cortisol DHEA-S Estradiol (E2) Free Testosterone Total Testosterone Folate (Folic Acid) Vitamin B12 Calcium Ferritin Iron (Serum) Magnesium Magnesium (Intracellular) Potassium Progesterone Sodium Transferrin CRP (C-Reactive Protein) Glucose (Fasting) HbA1c (Glycated Hemoglobin) ApoB (Apolipoprotein B) HDL Cholesterol Total Cholesterol Albumin AST (Aspartate Aminotransferase) Vitamin D (25-OH) Insulin (Fasting) Leukocyte Differential Creatine Kinase (CK) Transferrin Saturation Triglycerides Basic Blood Count
€399,-

Vitamin D (25-OH)

€35,-