My vitamin d level is 37 ng/ml, this is below optimal (50-70 ng/ml), i already take 1000 iu d3/day, what dosage should i take for levels 50-70 ng/ml?

Vitamin D dosing: Get a bottle of 5000 iu vit d. Take 4 caps/day for a month then retest vit d levels. If you are in the ref range (more than 55) you can drop the dose to 5000iu/day thereafter. If not optimal, continue 4 caps/day for another month.

Level normal: Your level is normal. If you take a d3 supplement, 2000 units/day will keep your levels normal, but it will take up to 3 mos to get in your system. Don't overdose trying to make a lab test "optimal".