Here is a list of the most toxic protein powders as reported in Consumer Reports as of July 2010.

Muscle Milk
EAS Myoplex
BSN Whey Protein
GNC Whey Protein
Designer Whey
Jillian Michaels Whey Protein
Optimum Nutrition
Six Star
Solgar

Here is a list of some of the chemicals and agents that are in most protein powders.

Artificial Flavorings: This is a list of just some of the artificial flavors in protein powder, there are many more.

Amyl Acetate: Is a bean and banana oil flavor.It can cause nervous system depression , indigestion, chest pain, headaches, fatigue and irritate the mucus membranes.

Benzaldehyde: Is an almond flavor that can cause central nervous system depression and convulsions.

Borneal: It can cause gastrointestinal irritation, seizures, confusion and dizziness.

Carvacrol: It can cause respiratory and circulatory depression.

Formic Acid: This is artificial cinnamon and has caused cancer in mice and may affect our kidneys.

Bacillus Coagulars GBI-30;6086: ( natural product) This contains maltodextrin , micro crystalline cellulose, and sodium bicarbonate used for bulking purposes of the product.

Mono and Diglycerides: ( natural product) This is an emulsifier. They promote inflammation and obesity, raise LDL( bad cholesterol)and  lower HDL( good cholesterol). It also increases the risk of heart disease, stroke and diabetes.

Potassium Chloride: Also known as potash. Sodium free substitute for salt. Used as chemical feed for livestock. It is also used in lethal injections or to stop the heart for heart surgery. Side effects include gastrointestinal discomfort, including nausea, vomiting, diarrhea and bleeding of the digestive trac.

Sodium Casein: It is used in many foods. It can cause allergic reactions because it acts as a histamine releaser. It also aggravates symptoms of autism.

Sodium Dioxide: Silica is a common additive in the production of foods, where it is used as a flow agent in powdered foods. It is also used to absorb water in hygroscopic applications.It is a primary component of diatomaceous earth which has many uses ranging from filtration to insect control. It is also the primary component of rice husk ash which is used for example, in filtration and cement making.

Sucralose: It is an artificial sweetener 600 times more sweet than sugar. Sucralose has been shown to increase PH levels in the intestines and contribute to increase weight gain.

Xanthan Gum: It is used in the food process for viscosity and can cause bloating and diarrhea.