Mixing and storage

Add 2 mL of bacteriostatic water to the 10 mg vial, which gives 5 mg in each mL, so 0.5 mg is 10 units and 1 mg is 20 units on an insulin syringe. Swirl gently until clear, never shake. Keep powder cool and dark, since melatonin breaks down in light. After mixing, keep it in the fridge in the dark and use it within 28 days.