How long does it take to raise vitamin D levels with supplements?

This question is about Nutrition

Elle Penner, MPH, RD

It can take anywhere from 1-6 months to raise vitamin D levels with supplements. How much your levels increase and how long it takes will depend on the dose and your baseline vitamin D levels. Factors such as age, weight, skin pigmentation, genetics, physical activity level, and sun exposure also impact the effectiveness and absorption of supplemental vitamin D. If you have very low vitamin D (<20 ng/mL), you will likely require more vitamin D supplementation to achieve an optimal level for good health (>40 ng/mL).

If your baseline vitamin D level is at or below 40 ng/mL, moderate daily supplementation of 1,000-5,000 IU vitamin D3 (cholecalciferol) may be appropriate, however, you should talk with a dietitian or your doctor to find the right dosage.

hand with ring holding vitamin capsule


  1. National Institutes of Health. (2021, March 26). Office of Dietary Supplements - Vitamin D. National Institutes of Health – Office of Dietary Supplements.

  2. Diamond, T., Wong, Y. K., & Golombick, T. (2013). Effect of oral cholecalciferol 2,000 versus 5,000 IU on serum vitamin D, PTH, bone and muscle strength in patients with vitamin D deficiency. Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA, 24(3), 1101–1105.

  3. Han, Q., Li, X., Tan, Q., Shao, J., & Yi, M. (2019). Effects of vitamin D3 supplementation on serum 25(OH)D concentration and strength in athletes: a systematic review and meta-analysis of randomized controlled trials. Journal of the International Society of Sports Nutrition, 16(1), 55.