A. The proteins in colostrum have almost no cystine content. Cystine is critically essential to the immune system. Although Growth Factors present in colostrum (including IGF-1, or Insulin-like growth Factor-1 which is effective in promoting muscle growth) are not affected by stomach acid, research published by one manufacturer of Colostrum (Vital Health News, Winter 1998, page 7) demonstrated that “the effectiveness of the immune factors present in colostrum is lowered by stomach acid.” Although the immune enhancing factors found in colostrum are often “preferable to single isolated immune components” (such as interferon, which is more likely to cause troublesome side effects), colostrum has NOT been demonstrated to be superior to isolated undenatured whey proteins such as bioactive whey protein. Colostrum (which is produced during the first 26 hours following birth by the mammary glands) is primarily composed of immunoglobulin and some lactoferrin. According to both laboratory experi