US regulators have proposed new restrictions on the soaring $US2 billion ($A2.2 billion) market in e-cigarettes, which until now have been free from federal oversight.
The changes would also apply to other, previously unregulated tobacco products, including cigars, hookahs, nicotine gels, and pipe tobacco.
"This proposed rule is the latest step in our efforts to make the next generation tobacco-free," said Health and Human Services Secretary Kathleen Sebelius in a press release announcing the reform.
The proposal by the US Food and Drug Administration (FDA) would require sellers to enforce a minimum age restriction on those who wish to buy the products, including requiring identification.
Companies would be barred from handing out free samples, and would be required to include health warning labels.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
They would also be prevented from advertising a lower health risk, compared to traditional cigarettes, unless the FDA confirms scientific evidence backing up the claim.
"Tobacco-related disease and death is one of the most critical public health challenges before the FDA," said Mitch Zeller, director of the FDA's Centre for Tobacco Products.
"The proposed rule would give the FDA additional tools to protect the public health in today's rapidly evolving tobacco marketplace," he added in the statement.
E-cigarettes are battery-operated devices that deliver vaporised nicotine into an aerosol inhaled by the user.
Their use by young people has been booming, with a December study by the US Centres for Disease Control and Prevention estimating that 10 per cent of high school students had used e-cigarettes.
A report earlier this month found that of the nation's nine manufacturers of e-cigarettes -- which are marketed under various names including vape pipes or e-hookahs -- six sell flavours such as Cherry Crush or Chocolate Treat that could appeal to children.
