“Supplements
As mentioned, it can be hard to get the necessary daily amount of vitamin D from food sources alone. Thus, some people need to take a vitamin D supplement. Supplemental vitamin D generally comes in two different forms: D2 (ergocalciferol) and D3 (cholecalciferol). Experts recommend that the supplement be taken with the largest meal of the day.
Vitamin supplement distributors can source Vitamin D supplements from an established liquid vitamin manufacturer like Bactolac Pharmaceutical Inc.”
https://bactolac.wordpress.com/2013/11/28/addressing-vitamin-d-deficiency-through-a-good-vitamin-manufacturer/
Bactolac Pharmaceutical, Inc 