I hate articles that give zero definition or even a hint at what “low dose” means.
Did I overlook it?
Also look at undefined frequency. A real test would have had the same frequency for both doses.
No you didn’t overlook it. It’s missing, along with information defining a “high’ dose.
Generally, 600 to 2000 IU is considered low-dose. Moderate low would be in the 4,000 to 5,000 IU range.
If you sat in a chair facing the sun (t-shirt/shorts), 30 minutes per day, at least three or four times a week, you would reach the low dose per week level (with zero cost). In this scenario, you’d only need the supplements in the fall/winter period.