Every ingredient we use is tested to USP standards (or applicable standards as required). Each one is evaluated by both the supplier and Axcentria’s lab to ensure its purity and quality. The presence of any of those substances in an ingredient would eliminate its use. Our bottles and caps are held to an equally high standard of cleanliness and materials content. However, Axcentria cannot control the choice of hardware and device used by the customer. Inferior grade hardware is often the source of these contaminants.