The reddit post was taking 50,000IU a day, which is usually the amount prescribed for someone to take once a week.

Your 4000IU isn't too much. Lots of the brands you see in stores are 5k for daily supplementation.

> Your 4000IU isn't too much.

By what metric? Jeez. People, you need to get your blood checked. There is no one-fits-all dosage. In winter, 4000 IU/d was enough to raise my blood levels well into the excessive range.

My 4000 units were after blood testing and also after genetic testing which showed some VDR mutations that might benefit from supplementation. As mentioned in another comment, that dose brings me slightly over 30 ng/ml, so basically borderline ok.

I fully agree that supplementation should always be combined with both blood testing and also a general medical evaluation.

FWIW: my functional provider recently noted low levels in my labs and I was already taking 2K IU daily. She bumped me up to 6K UI daily.

4,000 is perfect.

Current recommendations are 800 IU per day if you’re not significantly deficient. Always keep testing at least once a year or so. I took 5000 IU per day for a while, which ended up pushing me over 60 ng/ml. That’s considered too high a level and may have negative health effects.

I tested after taking 4000 IU daily for quite a while and ended up at 30.9 ng/ml, so I guess I have some buffer left. But I fully agree, regular testing is prudent when supplementing anything above common established levels.