From the Guidelines
For a vitamin D level of 17.6 ng/mL, I recommend taking 50,000 IU of vitamin D2 weekly for 8 weeks to raise your levels into the normal range (above 30 ng/mL). This recommendation is based on the guidelines from the NCCN task force report on bone health in cancer care 1. The report suggests that for patients with serum 25(OH) D levels below 30 ng/mL, a common regimen is prescription vitamin D (ergocalciferol) 50,000 IU weekly for 8 weeks, followed by a recheck of the serum 25(OH) D level.
- It is essential to note that vitamin D3 could be more effective in raising 25(OH) D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed, as stated in the report 1.
- However, the report also mentions that no difference in maintaining 25(OH) D levels was found when daily dosing was studied, which is why the weekly dosing regimen is recommended 1.
- After the initial treatment period, it is crucial to have your levels rechecked to determine the necessary maintenance dose, which may be 1000 IU of vitamin D2 or D3 per day, as suggested by the panel 1.
- It is also important to be aware of the potential risk of vitamin D toxicity, which may occur with daily doses of more than 50,000 IU per day that produce 25(OH) D levels larger than 150 ng/mL, as noted in the report 1.
From the Research
Vitamin D Supplementation
- The user's vitamin D level is 17.6, which is considered low 2.
- A study from 2011 found that commonly recommended dosages for vitamin D supplementation were insufficient to achieve a clinically relevant increase in 25-hydroxyvitamin D levels, and higher dosages were safe and effective under clinical practice conditions 2.
- The study suggested that supplementation with higher vitamin D dosages (2,000-3,000 IU/day) is required to achieve a relevant increase in 25-hydroxyvitamin D and normalization of parathyroid hormone (PTH) 2.
Dosing Recommendations
- A 2025 review emphasized that serum concentrations > 30 ng/mL (75 nmol/L) significantly lower disease and mortality risks compared to <20 ng/mL, and daily supplementation with 2,000 IU/day (50 mcg/day) of vitamin D3 can achieve this level 3.
- The review also suggested that a daily dose between 4,000 and 6,000 IU of vitamin D3 to achieve serum 25-hydroxyvitamin D levels between 40 and 70 ng/mL would provide greater protection against many adverse health outcomes 3.
- A 2019 systematic review and meta-analysis found that daily supplementation with both vitamin D and calcium was a more promising strategy for reducing the risk of fracture, with a 6% reduced risk of any fracture and a 16% reduced risk of hip fracture 4.
Considerations
- The user's low vitamin D level may be associated with increased risk of fracture, and supplementation may be necessary to achieve optimal levels 2, 4.
- The optimal dosage and duration of vitamin D supplementation may vary depending on individual factors, such as age, sex, and medical history 2, 3.
- It is essential to consult with a healthcare professional to determine the best course of treatment for the user's specific situation 2, 3, 4.