Vitamin D, 25-Hydroxy · low result
Vitamin D deficiency (low vitamin D): symptoms, what the levels mean, causes and what to check next
Short answer
Low vitamin D is the most common deficiency found on a blood test: little sun, darker skin, northern winters, indoor work, obesity, malabsorption and older age all lower 25-hydroxyvitamin D. The NIH calls below 12 ng/mL deficient and 12–19 inadequate; many clinicians aim for 30 or more. Most people have no symptoms; bone pain, muscle weakness and fractures appear with prolonged, severe deficiency. Replacement is straightforward and is checked with a repeat level after 8–12 weeks.
Medically reviewed by Youmna DiStefano, MD · Last reviewed November 2026
When does this result need same-day care?
- Severe bone pain with difficulty walking, or a fracture after a minor fall — prompt evaluation for osteomalacia or osteoporosis
- Muscle cramps, tingling or seizures with a low calcium — same-day care
What is the normal range for Vitamin D, 25-Hydroxy?
- age 18+: 30 – 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?
- Too little sun — winter at latitudes above about 37°N, indoor work, sunscreen, covering clothing, and air pollution; skin makes less vitamin D with age
- Darker skin, which needs several times more sun exposure to make the same amount
- Obesity — vitamin D is stored in fat and less reaches the blood; levels fall further after rapid weight loss is not the issue, but bariatric surgery is
- Malabsorption — celiac disease, Crohn's disease, bariatric surgery, pancreatic insufficiency, cystic fibrosis, cholestatic liver disease
- Low intake — few foods contain vitamin D (oily fish, egg yolk, fortified milk and cereal); exclusively breastfed infants without drops
- Medications — phenytoin, phenobarbital, carbamazepine, rifampin, glucocorticoids, some HIV drugs, orlistat and cholestyramine
- Kidney disease and nephrotic syndrome (loss of the binding protein in urine), and advanced liver disease, which cannot make 25-hydroxyvitamin D
- Pregnancy and breastfeeding, which increase demand
What symptoms go with low Vitamin D, 25-Hydroxy?
- None in most people — the deficiency is found on a routine test
- Deep aching bone pain and tenderness, especially the lower back, hips, pelvis and legs; muscle weakness and aches, difficulty rising from a chair
- Fatigue, low mood and frequent infections are commonly attributed to it, with weaker evidence
- Fractures from minor falls, a waddling gait and bowed legs with prolonged severe deficiency (osteomalacia in adults, rickets in children)
What do clinicians usually check next?
- Calcium, phosphorus and alkaline phosphatase — a high alkaline phosphatase with a low phosphorus suggests osteomalacia; parathyroid hormone, which rises to compensate (secondary hyperparathyroidism)
- Creatinine and eGFR, and magnesium, which is needed to activate vitamin D
- Celiac serology (tissue transglutaminase IgA) when the deficiency is severe, unexplained or does not correct with replacement
- A bone density scan when there have been fractures, prolonged deficiency, steroid use or other osteoporosis risk
- Replace under a clinician's guidance — the form and amount depend on the level, body weight and absorption — and recheck 25-hydroxyvitamin D after 8–12 weeks, then yearly once stable
- Note that routine screening of healthy adults is no longer recommended by the Endocrine Society (2024); testing is for people with symptoms, risk factors or bone disease
Follow-up tests available at TestWell: Magnesium Test ($18.99), Calcium Test ($16.99), Phosphorus Test ($16.99).
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 |
|---|---|---|---|---|
| Vitamin Deficiency Test Panel (D, B12 & Folate) | 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 Test (25-Hydroxy) | Test | $36.99 | No | 1–3 business days |
Common questions
What are the symptoms of vitamin D deficiency?
Usually none. With prolonged, severe deficiency: aching bone pain and tenderness in the lower back, hips and legs, muscle weakness and aches, difficulty rising from a chair, fatigue, and fractures from minor falls. Children develop rickets with bowed legs. Low mood and frequent infections are often attributed to it, with weaker evidence.
What vitamin D level is too low?
The NIH and Institute of Medicine call 25-hydroxyvitamin D below 12 ng/mL deficient, 12–19 inadequate and 20 or above sufficient for bone health; the Endocrine Society historically preferred 30 ng/mL or more. Below 10–12 ng/mL is where osteomalacia, high parathyroid hormone and fractures become likely.
How long does it take to correct a vitamin D deficiency?
Blood levels rise over weeks and plateau at about three months, which is why the repeat test is done 8–12 weeks after starting replacement. Bone pain and weakness improve over weeks to months. The right form and amount depend on how low the level is, body weight and whether absorption is normal, so replacement is set with a clinician.
Can you get enough vitamin D from the sun?
In summer, at midday, with arms and legs exposed for 10–30 minutes a few times a week, most light-skinned people can; darker skin needs several times longer, and above about 37°N latitude the winter sun is too weak from roughly November to February. Sunscreen, glass, clothing and age all cut production, which is why diet and supplements matter for many people.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.