I stay away from all Muscletech product as much as possible. If you like artificial Red #40 in your body, that's your perogative. They use that almost exclusively in their products, I would do more research on the long term affects.
Allura Red AC, also called Allura Red, Food Red 17, C.I. 16035, and FD&C Red 40, is a red azo dye. It is used as a food dye and its E number is E129. Allura Red AC was originally introduced in the United States as a replacement for the use of E123, , as a food colouring.
It has the appearance of a dark red powder. It usually comes as a sodium salt, but can be also be used as both calcium and potassium salts. It is soluble in water. In water solution, its maximum absorbance lies at about 504 nm.
Allura Red AC is Food and Drug Administration approved for use in cosmetics. It is used in some tattoo inks. It is used in many products, eg. orange soda.
Despite the popular misconception, Allura Red AC is not derived from the cochineal insect. The red coloring Carmine is derived from an insect.
Allura Red AC has few health risks associated with it in comparison to other azo dyes. Upon its introduction onto the market, there were fears that Allura Red AC was carcinogenic, studies have since shown that this is not the case, the initial reports of its consumption causing tumors have since been shown to have been caused by the presence of para-cresidine.
Para-cresidine is an important reactant in the manufacture of Allura Red AC and is a known carcinogen, further studies have since been conducted and none of them found any trace of para-cresidine to be present in food-grade Allura Red AC.
Allura Red AC may also cause an adverse reaction in the small minority of people with an aspirin intolerance or allergy, manifesting itself as a skin rash (Urticaria). It has also been implicated in cases of hyperactivity in young children.
Edit: source: wikipedia