GLC 1000 Powder (12.4 oz) GLC 1000 Powder is the world's only spectrum glucosamine formula scientifically engineered to optimize cellular uptake and utilization of the available composition. GLC 1000 is a 100% pure powder concentrate, giving you complete control over the accuracy and administration of each individual dose. GLC 1000 makes the perfect companion for older and less mobile dogs of all breeds, shapes and sizes.