A new study has revealed shocking trends among young people, with many getting hooked on what researchers call "alcopops of the nicotine world".
The Liverpool John Moores scientists surveyed 16,193 14-17 year-olds about e-cigarette use, finding 19% had tried "vaping" or used the devices regularly.
The findings were published in BioMed Central's Public Health Journal, with scientists who carried out the research calling for greater restrictions on access to e-cigarettes.
Researchers are worried the "normalised" smoking alternative may act as a gateway to real cigarettes as it mimics the effect and still retains the addictive effect of nicotine.
Prof Mark Bellis told BBC News: "To many people the numbers we've identified might come as a bit of a shock.
"This is just being drawn into a repertoire - another drug that people can use to experiment with rather than being seen as an alternative to tobacco."
He also added they were "providing a concentrated form of a highly addictive substance, with known problems associated with it, and we need to be very cautious about that and how we protect our young people."
Dr John Middleton, of the Faculty of Public Health, said: "We need to protect children and young people from the harms of nicotine by regulating electronic cigarettes.
"Our concern is that if we wait for proof that electronic cigarettes could act as a gateway to smoking cigarettes, it will already have happened and the tobacco industry will have been given the opportunity to recruit its next generation of smokers."
E-cigarettes are provided as a healthier alternative to smoking, but some consider them to be deceptive.
They provide a mist of nicotine, a highly addictive substance which can increase blood pressure and heart rate, and can have detrimental effects on the brain development of unborn children.
Nicotine has also been linked with atherosclerosis (fatty deposits growing in artery walls, restricting blood flow).