Medical devices don’t typically come in flavors like “Spiked Nog,” “Apple Jaxx,” or “Aphrodite’s Affair,” but proponents of e-cigarettes—introduced in 2006—have argued that the pen-shaped nicotine vaporizers could help cigarette smokers kick the habit. Now, a review of the scientific literature, published today, lends credibility to this claim, although the matter is far from settled.Conducted by the UK Cochrane Centre, the review focused on just two randomized controlled trials, but it also considered data from 11 cohort studies, which compared people who were already trying to quit with and without e-cigarettes. On balance, the data “suggest that electronic cigarettes can be helpful [for] stopping smoking and reducing cigarette consumption,” says lead author and behavioral scientist Hayden McRobbie of the Wolfson Institute of Preventive Medicine in London.After 1 year, trial participants who used the devices were more than twice as likely (4% versus 9%) to successfully quit compared with those who used a nicotine-free placebo vaporizer. Another 36% of e-cigarette users were able to reduce the number of traditional cigarettes they smoked by 50% or more. But 28% of placebo users also reduced their cigarette consumption by at least 50%, suggesting that some of the e-cigarette’s quitting power may be derived from the mere act of “smoking” it.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)Because there are so few studies investigating how well e-cigarettes work as a quitting tool, the review’s confidence levels are low and estimates for efficacy are likely to change. But all the same, McRobbie says he’d recommend e-cigarettes to a friend or family member who was trying to stop smoking, and he thinks that health care professionals should be more open to recommending the devices.The Cochrane review looked for signs of serious adverse reactions to the e-cigarette therapy, but found none. That’s certainly not to say that e-cigarettes are completely harmless. “We don’t know the risk of long-term use yet,” McRobbie says. Previous analyses of their vapors have turned up numerous toxic chemicals and heavy metals. Whether these compounds are present in doses large enough to cause long-term health concerns remains to be seen. But compared with the harms of tobacco, “the actual health effects are quite likely to be smaller because e-cigarette vapor … has fewer toxins in it,” says Suzaynn Schick a biologist at the Center for Tobacco Control Research and Education at the University of California, San Francisco.Of course, the safest thing to do is to avoid cigarettes—electronic or otherwise—altogether. But for those already addicted to nicotine, e-cigarettes may be the lesser of two evils. “I hope now the debate can move on to how best we can advise and support smokers using these products to stop smoking completely as soon as possible,” said Ann McNeill, a professor of tobacco addiction at the National Addiction Centre at King’s College London, in an official statement. The Cochrane review calls for further study, specifically comparing e-cigarettes with other methods of quitting like the patch in terms of safety and efficacy. “We need some more data to strengthen the evidence,” McRobbie says.