Do high levels of vitamin a lower vitamin d levels? i took topical retinol for a few months and later on was deficient in vitamin d through a blood test?

Vitamin D deficiency is common during the winter, especially if you have not gone out a lot. Topical retinol (vitamin A) or even oral vitamin A should not affect vitamin D level.

Although there seem to be no definitive conclusions regarding the interaction between Vit A and Vit D in humans , some animal studies show an increase in bone demineralisation when rats were given both vit a and vitd . It is thought that this antagonism between the two vitamins is at a molecular level .

Vitamin A levels do no affect Vitamin D. Vitamin D deficiency is very common. You can safely take 5000 units/day of vitamin D3 for three months and 2000 units/day after that. Wish you good health!

Vitamin D does not interact with other vitamins and in essence, acts like a hormone secondary to ability to manufacture in the skin secondary to sunshine. Vitamin A does not cause vitamin D deficiency and key to get your levels up to 50-70 ng/ml by supplementation.