Vitamin D dose
International units or micrograms
1,000 micrograms (mcg) in a milligram (mg)
1,000 milligrams (mg) in a gram (g)
1,000 grams in a kilogram (Kg)
1 kg is 2.2 pounds
IU mcg
400 10mcg
800 20mcg
1,000 25mcg
2,000 50mcg
4,000 100mcg
https://www.healthline.com/nutrition/...

US

42% of people have a vitamin D deficiency

82.1% of black people

69.2% of Hispanic people.
Higher blood levels = over 33 ng/ml or 82.4 nmol/l
Lower blood levels less than 12 ng/ml or 30 nmol/l
50% lower risk of colorectal cancer
Consuming 1,000 IU (25 mcg) daily would help 50% of people reach a vitamin D blood level of 33 ng/ml (82.4 nmol/l)
Consuming 2,000 IU (50 mcg) daily would help nearly everyone reach a blood level of 33 ng/ml (82.4 nmol/l)
Taking 1,000 IU (25 mcg) of vitamin D daily reduced heart disease risk by 10%
Consuming 1,000–4,000 IU (25–100 mcg) of vitamin D daily should be ideal for most people to reach healthy vitamin D blood levels.
However, don’t consume more than 4,000 IU of vitamin D without your doctor's permission. It exceeds the safe upper limits of intake and is not linked to more health benefits

https://link.springer.com/article/10....

https://link.springer.com/article/10....

https://www.bmj.com/content/356/bmj.i...

https://www.medrxiv.org/content/medrx...

https://www.medrxiv.org/content/10.11...

https://papers.ssrn.com/sol3/papers.c...

https://www.nature.com/articles/s4143... (pdf link)

https://endocare.hu/wp-content/upload... (pdf link)

https://tilda.tcd.ie/publications/rep... (p

https://www.thelancet.com/journals/la...