What is rBST?
Similar to humans, cows produce growth hormone, which is essential for normal growth and development. In cows, the naturally occurring growth hormone is called “bovine growth hormone” or “bovine somatotropin.”rBST, or recombinant bovine somatotropin, is a synthetic version of the naturally occurring growth hormone1.

Is rBST safe?
The U.S. Food and Drug Administration (U.S. FDA) approved rBST in 1993 for use in dairy cows to increase milk production. This approval was made after significant safety evaluation to ensure that milk from cows given with rBST was safe1.

How do I know if a product contains rBST?
The U.S. FDA does not require special labels for products produced from rBST-treated cows. Additionally, the U.S. FDA recommends, but does not require additional labeling on products that contain rBST-free claims. The additional labeling is intended to avoid misleading claims by clarifying that “no significant differences have been shown between milk derived from rBST-treated and non-rBST-treated cows.”

Products that have been certified organic by the U.S. Department of Agriculture (USDA) would only contain milk ingredients from non-rBST-treated cows.

Sources:
1Report on the Food and Drug Administration’s Review of the Safety of Recombinant Bovine Somatotropin (2009, April 23).
In U.S. Food and Drug Administration. Retrieved May 20, 2014, from
http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm130321.htm.