Vitamin D dosing varies based on age, deficiency status, and individual factors. How much vitamin d should i take depends on whether you’re addressing deficiency or maintaining adequate levels.
RDA recommendations
Per Institute of Medicine:
- Adults under 70: 600 IU/day
- Adults 70+: 800 IU/day
- Pregnancy/lactation: 600 IU/day
Many clinicians and the Endocrine Society recommend higher doses (1500-2000 IU/day for adults).
For deficiency treatment
Mild deficiency:
- 1000-2000 IU daily
- Recheck levels at 8-12 weeks
Moderate-severe deficiency:
- 4000-8000 IU daily for 6-12 weeks
- Or 50,000 IU weekly for 6-12 weeks (prescription D2 typically)
- Then maintenance 1000-2000 IU daily
Upper limits
- Tolerable upper intake: 4000 IU daily for adults
- Sustained higher doses risk hypercalcemia
- Toxicity typically requires 10,000+ IU daily for months
Factors affecting needs
- Body weight (heavier individuals may need more)
- Skin pigmentation (darker skin needs more sun for synthesis)
- Latitude and season
- Sun exposure
- Age
- Malabsorption conditions
Frequently Asked Questions
Is 5000 IU per day too much?
Higher than RDA but generally safe. Above tolerable upper limit (4000 IU). Discuss with provider.
Should I take 50,000 IU weekly?
Used for treating deficiency. Equivalent to ~7000 IU/day. Prescription typically.
Can I overdose on vitamin D?
Difficult with standard supplementation. Sustained very high doses can cause hypercalcemia.
Should I get tested before supplementing?
For modest doses (under 2000 IU), testing optional. For higher doses, testing helpful.
How often should I check vitamin D levels?
Annually for those on supplementation; more frequently when adjusting doses.
The bottom line on vitamin D dosing
Most adults benefit from 1000-2000 IU daily. Higher for documented deficiency. Tolerable upper limit 4000 IU. Discuss with healthcare provider.