Dietary supplements are far more processed than food, so the chances are they are safer than food. The FDA has put up rigorous and effective safeguards to protect us. A primary goal of NNFA is to educate both the public and manufacturers. We also want to make sure that information for the public is factual and not sensationalized, and that consumers understand that glandulars are different from vitamins, minerals, and amino acids. To pass this inspection, companies must have rigorous methods of identifying raw materials and documenting their source.
Different tissues carry different risks of infectivity.
The following list of highest through smallest risk of infectivity was gathered from an FDA letter to dietary supplement manufacturers and other US government documents. Highest risk Especially brain tissue and spinal cord, possibly also retina of the eye. Medium risk Adrenal gland, cerebrospinal fluid, dura mater, ileum, lymph nodes, pineal gland, pituitary gland, placenta, proximal colon, spleen, tonsil. Low risk Bone marrow, distal colon, liver, lung, nasal mucosa, pancreas, sciatic nerve, thymus gland. Skeletal muscles and milk have never shown any infectivity.