I personally purchase all my supplements from Swansonvitamins.com, but there are plenty of reputable vitamin companies out there (Twin Labs, Solgar, Solaray, Now). I would avoid buying supplements from the dollar stores, discount pharmacies, or those not produced in the US. I look for capsule forms and avoid tablets if at all possible, since they are easier to swallow and more readily absorbed in the digestive system. Of course, liquid forms of vitamins are probably the most easily absorbed, but are messier to take and may have undesirable tastes and not all nutritional supplements are amenable to this form due to solubility and stability issues.

One should keep in mind that all supplements are not created equal.

In some cases there are a variety of chemical forms for individual vitamins. Let’s take vitamin E for example: it comes in a synthetic form (dl-alpha tocoferol) and a natural form (d-alpha tocoferol). While they are basically the same molecule, they are arranged differently spatially and the body does not recognize the synthetic form. So the synthetic form is inferior to the natural form being inactive and potentially toxic.

To further confuse matters, there are other naturally occurring tocoferols (like gama tocoferol) and related naturally occurring compounds called tocotrienols. While the less complete synthetic and naturally occurring vitamin E supplements may appear to be a better price they are anything but a bargain health wise. This also applies to Vitamin D, which comes in a variety of forms (vitamin D2 is inferior to vitamin D3). This is another reason why I like Swanson’s Supplements since most of their products are in capsule form and they offer the more active forms of these supplements.

Finally, avoid the notion that if a little bit is good then more is even better.

This can get you in trouble with fat soluble vitamins such as vitamin A and D, which can be toxic and with trace minerals especially selenium. While multivitamins may not provide enough of a particular supplement, you may be getting too much if you’re taking an additional supplements along with your multi-vitamin. So be sure to check your multi carefully for the amounts of these individual constituents.