How much vitamin D per day, by age and need
The RDA is 600 IU/day under 70 and 800 IU/day over 70. Common maintenance is 1000-2000 IU/day; the upper limit is 4000 IU/day. The daily number by age, blood level, and source.
What people ask us next.
- How much vitamin D should I take per day?
- The RDA is 600 IU/day for adults aged 1-70 and 800 IU/day from age 71 (IOM 2011; NIH ODS). Common real-world maintenance is 1000-2000 IU/day, the range that more reliably holds a sufficient blood level; VITAL used 2000 IU/day. The tolerable upper limit is 4000 IU/day. Without a blood test, 1000-2000 IU/day of D3 is a reasonable low-risk default for most adults.
- Is 2000 IU of vitamin D per day too much?
- No. 2000 IU/day is well under the 4000 IU/day upper limit and is the dose used in the VITAL trial (Manson et al. 2019). It is a common maintenance dose that helps hold serum 25-OH-D in the 30-50 ng/mL target band, especially through winter. It is not a high or risky dose for healthy adults; the risk territory starts well above the 4000 IU/day upper limit.
- How much vitamin D per day to correct a deficiency?
- That should be guided by a blood test and a clinician. A measured deficiency (serum 25-OH-D below 20 ng/mL) is often corrected with a higher loading dose for several weeks, then a maintenance dose of 1000-2000 IU/day, with a retest at 8-12 weeks. The correction dose is deliberately higher than maintenance and time-limited, which is why it belongs under clinician oversight rather than open-ended self-dosing.
- Can you take too much vitamin D per day?
- Yes, but it takes a lot. Toxicity comes from supplements, not sun, and presents as hypercalcemia. It generally requires sustained intake well above the 4000 IU/day upper limit, often around 10,000 IU/day for months (NIH ODS). Staying at or below 4000 IU/day without a measured deficiency keeps the risk near zero, so routine megadoses are needless.
- Should I take vitamin D with food?
- Yes. Vitamin D is fat-soluble, so taking it with a meal that contains some fat improves absorption. Timing of day does not matter much; consistency does. A daily 1000-2000 IU D3 capsule with breakfast or dinner is a simple, effective routine. Choose D3 over D2, which raises and holds blood levels less effectively (Tripkovic et al. 2012).
- Do I need a blood test before deciding the dose?
- It is the only way to dose precisely. The marker is serum 25-hydroxyvitamin D; 30-50 ng/mL is a common sufficiency target and below 20 ng/mL is deficient. A maintenance dose of 1000-2000 IU/day is low-risk without testing, but anyone using higher doses or correcting a suspected deficiency should test, then retest in 8-12 weeks. See our what vitamin D does page for how the blood level drives the effect.
Every claim, cited.
- [01]Institute of Medicine. 2011. Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press. RDA 600 IU/day (ages 1-70), 800 IU/day (71+); tolerable upper intake level 4000 IU/day.
- [02]NIH Office of Dietary Supplements. Vitamin D Fact Sheet for Health Professionals. RDA, upper limit, serum 25-OH-D thresholds, and toxicity from supplements.
- [03]Manson JE, Cook NR, Lee IM, et al. 2019. Vitamin D supplements and prevention of cancer and cardiovascular disease (VITAL). N Engl J Med 380(1):33-44. 2000 IU/day maintenance dose, n=25,871.
- [04]Tripkovic L, Lambert H, Hart K, et al. 2012. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D: a systematic review and meta-analysis. Am J Clin Nutr 95(6):1357-1364. D3 superior to D2.
- [05]Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. 2011. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 96(7):1911-1930. Defines sufficiency as serum 25(OH)D above 30 ng/mL and uses a 50,000 IU weekly loading regimen for deficiency.
The Larderlab Team builds evidence-led frameworks for eating, lifting, and stocking a kitchen. We cite every claim. We publish the spreadsheet when possible. We buy what we review at retail price. When new data lands, we revise with a dated note.
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