The linked study uses a daily dose of 6,000IU, and references two studies (13,26) which also tout the benefit of supplementing Vitamin D at a 3,000IU dose and a

The linked study uses a daily dose of 6,000IU, and references two studies (13,26) which also tout the benefit of supplementing Vitamin D at a 3,000IU dose and a 3,332IU dose, both daily. The two studies which are referenced (27,28) that do not find any significant benefits followed a different dosing strategy: 20,000IU and 60,000IU, weekly. It seems like daily, large doses is the best method for supplementing vitamin D. I've seen it suggested to pair vitamin D supplementation with calcium and magnesium [1]. [^1]: https://pubmed.ncbi.nlm.nih.gov/32972636/ https://pubmed.ncbi.nlm.nih.gov/32972636/