*** Not all supplements carry the same quality of nutrients. Vitamins and minerals in their singular form can come in different forms. For example, magnesium comes as oxide, citrate and glyconate – citrate and glyconate being more absorbable than oxide. Here are some supplement forms we should avoid: - **Calcium as Calcium Carbonate:**  This is the least absorbable forms of calcium on the market. A very small percentage is actually absorbed. - **Magnesium as Magnesium Oxide:** The least absorbable, cheapest form of magnesium. - **Iron as Ferrous Fumarate:** This form of iron is incredibly constipating. - **Vitamin E as DL-Alpha Tocopherol:** This is vitamin E and they are using two forms. The "D" form which is natural and the "L" Form which is synthetic. The "L" form is used to water-down the more expensive, more bioactive "D" form. - **The B vitamins**: Citing anywhere from 1.1 mg to 15 mg per vitamin is a concentration so low as to have no impact on energy level. - **Nickelous Sulfate and Tin:**  I was unable to locate any references discussing a need for humans to supplement with nickel or tin. *** **References**: - [The Truth Behind Centrum: Supplement Or Chemical Cocktail?](https://www.meghantelpner.com/blog/the-truth-behind-centrum-doing-more-harm-than-good/)