This question is about Nutrition
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.
National Institutes of Health. (2021, March 26). Office of Dietary Supplements - Vitamin D. National Institutes of Health – Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
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. https://doi.org/10.1007/s00198-012-1944-7
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. https://doi.org/10.1186/s12970-019-0323-6