I came across an online article about "The Bad Combination For Supplements". So, I would like to share some of the interesting points here. The bad combination doesn't mean harmful for human body. One supplement is absorbed in body, but the other is hardly done. In that sense, it is more of the wrong combination than the bad one, to be exact. This is a matter of when we should take those kinds of supplements. The following examples are the combination for supplements to avoid and they counteract each other. 1)Calcium(Ca)+Iron(Fe) : If you take Fe with vitamin C, at least two hours later, you'll have to take Ca with another meal. 2)Zinc(Zn)+Cupper(Cu) : If you take Zn of over 25mg, you'll have to take Fe of a few mg. 3)Iron(Fe)+Green Tea/Coffee : If you take some coffee or tea, you'll have to take Fe at least a few hours later. If you take plenty of supplements for calcium, they prevent human body from absorbing magnesium(Mg), iron and zinc. So does High-does zinc. It causes cupper consumption slowly and one of the most wrong combinations. That's why practical rules which can cover these kinds of failure are that you don't take a single calcium supplement with supplement of a single iron or zinc at the same time. This habit will help remove typical potential competition of suppeiments each other. It's hard to make a time schedule for supplement. Instead, you'll just have to split some supplements into two group adn take each at breakfast and dinner. You should take Fe with vitamin C at breakfast and take Ca, Mg and Zn. Taking Mg just before sleep can help you relax.