Daily morning and afternoon exposure to bright light might actually be more important to reducing depression than direct vitamin D supplementation. Low vitamin D might just be an indicator that you are not getting enough sunlight. Sunlight also affects melatonin and serotonin levels, and synchronizes your Circadian rhythm. Not sure why that article doesn't talk about Seasonal affective disorder (SAD), and how bright…
Anecdotally agree with this. I have vitamin D deficiency, was given 50,000 IU a week vitamin D to get it up. Never worked. Went to the beach one week and got blood tested again and my vitamin D levels climbed significantly. Now I make it a point to get outside and sunlight
https://www.tandfonline.com/doi/abs/10.1080/07315724.1994.10...