* Melatonin should be Pharmacy grade. Pharmacy grade melatonin has a USP label printed on the bottle. The USP stands for United States Pharmacopeia. It provides testing and sets standards for food ingredients, medicines and food supplements. Products that meet the requirements of USP can display the USP Verified Dietary Supplement Mark on the product label. When you are buying USP grade liquid melatonin, you are assured that you are getting high quality melatonin sleep aid.
* Melatonin should be synthetic not from animal source. Animal based melatonin can be contaminated with viruses.
* Melatonin should not be mixed with other active ingredients like vitamins, to lessen the chances of getting complications.
* Melatonin purity should be 99% or higher.
* Melatonin supplements should be bought from reputable brands. It is always a good idea to look for a reputable brand of Melatonin Supplement because melatonin is sold as a food supplement and not as a medicine. The Food and Drug Administration does not regulate Melatonin Supplement manufacturers so the quality and quantity of varies from manufacturer to manufacturer.
* Consider using sustained release melatonin versus regular release melatonin.