A group of experts convened by the U.S. government concludes there is not enough evidence to support using e-cigarettes to quit smoking. The U.S. Preventive Services Task Force says medicines, including nicotine replacement products, along with behavior modification programs, are more effective.

The task force conducted an in-depth review of studies of smoking cessation methods, Time reports. “There was not enough information to determine whether e-cigarettes are more helpful or harmful for smoking cessation,” the experts wrote.

Both smoking cessation medications and nicotine replacement products are more effective than e-cigarettes in helping people quit, the report notes. Using medications and nicotine replacement products together are even more effective. Using behavioral modification programs, such as support groups and counseling sessions, can further improve the odds of quitting smoking, the experts said.

“We have an embarrassment of riches in terms of a menu of things to offer patients who want to quit smoking,” said task force member Dr. Francisco Garcia, Director and Chief Medical Officer of the Pima County Health Department in Arizona. “But every individual is different; some might respond better to behavioral therapy, some might respond better to varenicline, some might feel nicotine replacement is important to bridge them away from tobacco use.” Varenicline, sold as Chantix, is a smoking cessation medication.

The task force found that not enough studies have been done on the effects of smoking cessation medication on developing fetuses, and recommended pregnant women rely on behavioral, non-drug strategies to help them quit.