Unfortunately, internet blog sites are perpetuating misinformation and taking scientific principles out of context that ultimately lead to unnecessary fear and misplaced assumptions regarding various products, ingredients, etc.  Regarding magnesium stearate (stearic acid), there certainly seems to be some misconceptions circulating. 
Firstly, its classification as a demonized “interesterified fat” may be inappropriate. Stearic acid is a naturally occuring fatty acid. It can be chemically modified into an interesterified fat, however is not one by itself.
Secondly, the stearic acid conspiracy among bloggers has blown its presumed negative effects out of proportion, and a quick review of the scientific literature suggests that its effects have yet to be proven as negative. “Even though stearic acid is a saturated fat, studies have suggested that it has little effect on blood cholesterol levels.”  This comment was taken from the conclusion of a peer-reviewed, independent study comparing the effects of stearic acid, trans fatty acids, and dairy fat on serum lipid profiles.  Read the abstract here: http://www.ajcn.org/cgi/content/abstract/65/5/1419 
Lastly, if stearic acid is to be lumped into the “trans fat” category, be aware that the levels contained in dietary supplements are essentially negligible.  For reference, an order of fast-food fries contains 8 grams of trans fat.  The average per capsule dose of stearic acid from a NeuroScience, Inc. product is less than 10 milligrams.  Doing the math, one would have to consume 800 capsules to ingest the stearic acid/trans fat equivalent of an order of fries.
And for clarification purposes, stearic acid is included in dietary suppements as a “flow agent”, a necessary ingredient to facilitate the encapsulation process. NeuroScience is sensitive to the concerns of our customers and takes steps to ensure the safety of our products. We request that our manufacturers minimize the use of “unnatural” ingredients. We also design our formulas to maximize capsule space and minimize the need for fillers, binders, etc.