The first article you cited is about vitamins A & E, which are also considered antioxidants, and there are problems with too much A or synthetic E. That's not the same as astaxanthin or resveratrol.

As a pharmacist who has researched vitamins and supplements thoroughly, I do not believe you can overdose on astaxanthin. It's not present in many food sources, so you can't rely on food for it. Up to 12 mg a day is great--beyond that, your fat storage becomes saturated and you eliminate excess, so it's a waste of your money. I take 8 mg daily, in split doses, and I don't sunburn anymore because it's a natural internal sunscreen.

If you're only taking 500 mg a day of vitamin C, I'd tell you to take 1000 mg daily in divided doses.

Sadly, food quality, even organic, is not what it used to be. Our soils are depleted and not as nurturing as in the past. In the 1940s, you could get all the vitamin A you needed from 2 peaches....now it takes 40 peaches. So I believe in supplementation even with a great diet.

I agree that there comes a point where you're taking too much, but I don't believe it hurts your body to take a lot of antioxidants (just not A or synthetic E), but it sure hurts your wallet. I think everyone should take at least one fat-soluble antioxidant and one water-soluble antioxidant daily.