LYONS, Colo. — Since May, a string of states have passed laws that give critically ill patients the right to try medications that have not been approved by the Food and Drug Administration.

Deemed “Right to Try” laws, they have passed quickly and often unanimously in Colorado, Michigan, Missouri, Louisiana and Arizona, bringing hope to patients like Larry Kutt, who lives in this small town at the edge of the Rocky Mountains. Mr. Kutt, 65, has an advanced blood cancer and says his state’s law could help him gain access to a therapy that several pharmaceutical companies are testing. “It’s my life,” he said, “and I want the chance to save it.”

The laws do not seem to have helped anyone obtain experimental medicine, as the drug companies are not interested in supplying unapproved medications outside the supervision of the F.D.A. But that seems almost beside the point to the Goldwater Institute, the libertarian group behind legislative efforts to pass Right to Try laws. “The goal is for terminally ill patients to have choice when it comes to end-stage disease,” said Craig Handzlik, state policy coordinator for the Goldwater Institute, based in Arizona. “Right to Try is something that will help terminally ill people all over the country.”

Legislators in 10 other states will introduce these bills in 2015, Mr. Handzlik said, and lawmakers in Kansas, Tennessee, Texas and Wyoming have already filed bills or announced intentions to do so. Critics of the laws like Dr. David Gorski, a surgeon in Michigan who blogs about medical issues, call them “a cruel sham.”