Which Viridian magnesium should I start with?
Bisglycinate, particularly if other forms have not agreed with you. Citrate is the well absorbed, cheaper alternative.
Why does Viridian sell four different magnesiums?
Because they differ in absorption and tolerance. It is not the same product relabelled.
Is the powder better than capsules?
Not better, but more flexible – you can vary the amount, and there is nothing to swallow.
When is the best time to take magnesium?
With food, and many people prefer the evening. The important part is with food.