A new study concludes many smokers who try e-cigarettes find them less satisfying than regular cigarettes. The researchers say this suggests e-cigarettes may not be a useful tool to help a significant number of smokers quit.

E-cigarettes, also known as Electronic Nicotine Delivery Systems, or ENDS, “need to improve as a satisfying alternative or the attractiveness and appeal of [a] regular cigarette must be degraded to increase the potential of ENDS replacing regular cigarettes,” according to lead author Dr. Terry F. Pechacek of Georgia State University’s Tobacco Center of Regulatory Science.

The study found e-cigarettes helped a small group of smokers quit regular cigarettes, HealthDay reports.

The researchers included 729 current and former smokers who had tried e-cigarettes. Of these, 101 had quit all smoking, and 43 had switched from regular cigarettes to e-cigarettes. Of the 585 current smokers, 58 percent said they had tried e-cigarettes but did not use them anymore. The remainder of the current smokers decided to smoke both traditional and e-cigarettes.

The findings appear in Nicotine & Tobacco Research.

The FDA announced in May it is extending its oversight to all tobacco products, including e-cigarettes. The agency will ban sales of e-cigarettes, cigars, pipe tobacco and hookah tobacco to people under age 18.

Companies will be required to submit all tobacco products to the FDA for regulatory review. They will have to provide the agency with a list of product ingredients and place health warnings on their product packages and in ads.

The new rule, which goes into effect in 90 days, will not allow e-cigarettes, hookah tobacco or cigars to be sold to anyone under the age of 18 years (both in person and online); require age verification by photo ID; prohibit the selling of covered tobacco products in vending machines (unless in an adult-only facility); and prohibit the distribution of free samples.