The synthetic hormone, which stimulates milk production in dairy cows, has sparked controversy since it was first approved by the Food and Drug Administration in 1993. Farmers can produce more milk per cow and thereby take in more revenue by using the hormone, but advocacy groups have questioned its effects on humans.

Chipotle said it is the first national restaurant chain to get rid of rBGH entirely from its menu items.

The chain said it began using rBGH-free sour cream last year and has begun switching to rBGH-free cheese. The switch will be complete by the end of the year, the company said.