IMO 4,000 IU is not nearly enough D3. The doctors I have quoted all agree that 8,000 or more IU's are needed to get your blood level to the required 70+ ng/ml. At home inexpensive blood test here:
We would want these co-factors anyway just for optimal health, and powering up the immune system. Also do an internet search, "Benefits of xx" to see all of the additional health benefits of each co-supplement.