1000 wont likely do anything for you, get a Vit D 25 test done at your doctor.

to increase your vitamin d3 to at least 50 to 70 you might need 5000 to 7000 iu per day and it takes 3 months for the results to be seen in the blood work.

I take 6000iu liquid vitamin d3 per day and my levels are pretty stable at 53 to 65