Whats the regular dosage for supplements for a 26 year old thats low (23- number on lab results) in vitamin d??

Data suggest a dose of 4,000IU/d is well tolerated by most and can be continued long term. Some docs use higher dosing for deficiencies when they follow blood levels. A standard 2,000 IU/d is a common supplement for extended use.

You can safely take 4000 units of vitamin D3 daily. Depending on your weight, after 3 months at this dose, you may be okay with 2000 units/day.