Here’s a list of the 20 most common supplements, with recommendations on when to stop them before doing a blood test:
Vitamin D: stop 5 to 7 days before.
Vitamin B12: stop 5 to 7 days before.
Vitamin B9 (Folic Acid): stop 4 to 5 days before.
Iron: stop 24 hours before.
Zinc: stop 2 to 3 days before.
Magnesium: not required, but if you want a baseline level, stop 2 to 3 days before.
Calcium: stop 1 to 2 days before.
Omega-3 (EPA/DHA): stop 5 to 7 days before.
Multivitamins: stop 5 to 7 days before.
Creatine: stop 3 to 5 days before.
Probiotics: no need to stop.
Vitamin C: stop 1 to 2 days before if it's being measured specifically.
Vitamin E: stop 3 to 5 days before.
Vitamin A: stop 5 to 7 days before.
Coenzyme Q10: stop 2 to 3 days before.
Curcumin: stop 2 to 3 days before.
Ashwagandha: stop 3 to 5 days before.
Melatonin: no need to stop, unless a hormone panel is being tested.
Collagen: no need to stop.
Selenium: stop 2 to 3 days before.