that's an interesting question. Most people take one tablet twice a day from what I read in this community. I know there are times when I wish I didn't have to take the second one if I'm going out in the evening, for example. There are supplements which have all the AREDS2 formulation but less zinc, and these come as one tablet per day. This makes me personally think that it's the full 80 mg dose of zinc which may be tough on our stomach if taken all together. I don't know the answer as it's a medical question, but this may shed more light on the subject. Wendy, Patient Leader.