People should try to take any supplements at the same time each day, as this may help form a habit and make it less likely for a person to forget to take the supplement.
However, the NIH warns that people should not take a magnesium supplement within 2 hours of oral bisphosphonates, such as Fosamax.
Additionally, people should take a magnesium supplement at least 4 to 6 hours before taking tetracycline or quinolone antibiotics, or at least 2 hours afterward.