Vitamin D, 25-Hydroxy · low result
What does a low Vitamin D, 25-Hydroxy mean?
Short answer
Low vitamin D is very common — limited sun exposure, darker skin, northern latitude, indoor work, obesity, malabsorption and older age all lower 25-hydroxyvitamin D. The NIH considers below 12 ng/mL deficient and 12–20 ng/mL inadequate; many clinicians aim for 30 ng/mL or more. Replacement is straightforward; retest 8–12 weeks after starting to confirm the dose works.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
What is the normal range for Vitamin D, 25-Hydroxy?
- age 18+: 30.0 – 100 ng/mL
Common in people with limited sun exposure, darker skin, obesity, or absorption issues. Supplementation is often used to correct it.
Full reference table, citations and testing options: Vitamin D, 25-Hydroxy biomarker page.
What are the common causes of low Vitamin D, 25-Hydroxy?
- Little sun exposure: winter, indoor work, sunscreen, covering clothing
- Darker skin (less D synthesis per unit of sun)
- Obesity (vitamin D is sequestered in fat)
- Malabsorption: celiac disease, Crohn's, bariatric surgery
- Kidney or liver disease; some anticonvulsants and glucocorticoids
What symptoms go with low Vitamin D, 25-Hydroxy?
- Often none
- Bone and muscle aches, proximal weakness
- Fatigue, low mood
- Fractures or bone softening when severe and prolonged
What do clinicians usually check next?
- Calcium, phosphorus and PTH if very low or if bone symptoms are present
- Consider celiac screening when there's no obvious reason
- Retest 25-hydroxyvitamin D 8–12 weeks after starting supplementation
Follow-up tests available at TestWell: Calcium ($26.99), PTH (Parathyroid Hormone) ($59.99), Phosphorus ($18.99).
If you're correcting a low level, retest about 3 months after starting supplementation — that's roughly how long 25-hydroxyvitamin D takes to plateau on a steady dose, per the Endocrine Society's deficiency guideline. Once in range, many people recheck annually, often in late winter when levels are lowest.
How do you recheck Vitamin D, 25-Hydroxy?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Basic Vitamin Deficiency Panel | Panel · 3 tests | $89.99 | No | 1–3 business days |
| Post-COVID Recovery Panel | Panel · 7 tests | $99.99 | Yes | 2–4 business days |
| Men's Health Panel | Panel · 8 tests | $139.99 | Yes | 2–5 business days |
| Vitamin D, 25-Hydroxy | Test | $41.99 | No | 1–3 business days |
Common questions
What vitamin D level is deficient?
Below 12 ng/mL is deficient and 12–20 ng/mL inadequate by NIH criteria; the Endocrine Society and many labs flag below 20 or 30 ng/mL as low.
How long until my level rises?
25-hydroxyvitamin D has a two-to-three-week half-life, so the new steady state takes about two to three months. Retest at 8–12 weeks.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.