I have just started using this product and I can definitely say that one of the best parts of this product is that there are no added chemicals or artificial colour or artificial preservative besides the main ingredient of quercetin. All other manufacturers will add multiple chemicals like magnesium stearate or artificial colour to the main ingredient which will always harm human health in the long-term. If you see a supplement that contains only the main ingredient in a vegetarian capsule, then that's the purest form of supplement one can use.