The typical American meathead method of supplementation is this: "If a little in a diet is supposed to be good, then prolonged usage of isolated megadoses must be better." If we just used a little commonsense, we'd know it isn't what's healthiest... When it comes to our supplements, we don't even know if they work, let alone if they might be harmful when taken in megadoses and uninterrupted for months and months.
I've always believed (but not necessarily acted accordingly) that everything, and dietary supplementaries especially, should be consumed in moderation, at least long term. If you want to go hog wild on something, fine! But don't go hog wild forever. Take a break from it. Girl Scout cookies? Go for it! I can eat a box of those peanut butter patties in one sitting no problem. BUT, I don't do that more than once or twice a year. Fasting? Fine, but not every week. Smolov? Fine, but not months and months of it. Caffeine? Fine, but is a lot of it every single day preferable? Vitamins float your boat? Fine, but not always and forever.
The situation for plants, herbs, and dietary supplements is different. [than drugs] Because of the Supplement Act, the FDA doesn't regulate them, so they don't have to be tested before they're sold. Sometimes supplements are tested by the National Center for Complementary and Alternative Medicine (NCCAM), a branch of the National Institutes of Health. One difference between the FDA and NCCAM is that the FDA requires products to be tested before they're sold, whereas NCCAM might test some products after they've been put on the market. If researchers funded by NCCAM find that dietary supplements don't work or have harmful side effects, they publish their results in scientific journals. No product recall. No change in the label. No FDA warnings. If people don't read scientific journals, they don't know that claims on the label are false and misleading.
Do You Believe In Magic?, pg. 96