Five stars because the only way I can take C is in the buffered form. Anything acidic causes problems with a sensitive bladder. A second reason for five stars is that I have come to trust Solaray. Their forumulas are always in line with latest reliable information and research on supplements.
My son has autism and the Super Bio-Plex Vitamin C & Bioflavonoids increased his ability to process information, increased his functional and expressive speech within the first 2 weeks. We use high doses.