25-OH Vitamin D3 details
What 25-OH Vitamin D3 shows
25-hydroxyvitamin D3 is the main circulating form of vitamin D and the best overall marker of your vitamin D status. Your body produces D3 in the skin from sun exposure and also absorbs it from animal-based foods (like fatty fish and egg yolks) and many supplements. Low levels are common and are linked to weaker bones, increased fracture and fall risk, and have been studied in connection with immune function and mood, though evidence for some of these associations is still evolving. Very high levels, usually from over-supplementation, can lead to excess calcium absorption and, in severe cases, toxicity. Most standard vitamin D panels report this value as 'Vitamin D, 25-OH, Total' — combining both D2 and D3 — since D3 is typically by far the larger contributor.
Tests that include 25-OH Vitamin D3
This panel measures total 25-OH vitamin D, 25-OH vitamin D2, and 25-OH vitamin D3 to assess nutritional deficiencies and monitor nutrient supplementation.
- Vitamin D, 25-OH, Total The combined measure of both major forms of vitamin D (D2 and D3) in your blood — the standard test used to assess overall vitamin D status.
- 25-OH Vitamin D2 The form of vitamin D your body makes from plant-based (D2) supplements or fortified foods. Reflects how much vitamin D you're getting from these sources.
- 25-OH Vitamin D3 The main form of vitamin D your body produces from sun exposure or gets from animal-based foods and supplements. Shows the D3 part only; overall vitamin D status is judged on total 25-OH vitamin D.
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