is consensus that they do work so long as the stated potency matches what is claimed by the label.

Commercial lactase is used as a medication for lactose intolerance. Since it is an enzyme, its function can be inhibited by the acidity of the stomach. However, it is packaged in an acid-proof tablet, allowing the enzyme to pass through the stomach intact and remain in the small intestine. In the small intestine it can act on ingested lactose molecules, allowing the body to absorb the digested sugar which would otherwise cause cramping and