The brand of "C" I take is Costco's Kirkland Signature [because it is the least expensive brand of tablets I have found]. Basically, all I am looking to ingest is plain "old" ascorbic acid, although additionally mine just happens to come with 10% citrus bioflavonoids [which are composed of 10% hesperidin and rutin]. It also has a very small amount of rose hips in it. But again, it is the pure ascorbic acid that I am after, as it is this that has the proven health [and disease fighting] benefits.