Backing a ban, Malaysian religious leaders this month declared a fatwa on the "un-Islamic" habit, but it remains to be seen whether the decree will dampen enthusiasm.
"The business is growing very fast because there are many people trying to convert from tobacco smoking to vaping," Vape Empire`s co-founder Muhammad Sharifuddin Esa said, adding that his business has expanded to 57 locations since it opened just two years ago.
The pastime has proved a particular hit in the moderate, Muslim-majority nation, where other vices such as alcohol and drugs are especially frowned upon.
Now several Malaysian states say they may impose a ban from January 1 and have threatened to stop issuing new merchants` licences -- a potential blow to a sector worth an estimated 2.8 billion ringgit ($650 million) last year, according to reports.
Health risks debated
The industry, which is expected to grow by more than 13 percent year-on-year to 2025, is currently unregulated, and many say forbidding e-cigarettes -- already outlawed in Thailand and Singapore for health reasons -- is a big mistake.
"The government must regulate and not ban, because vaping is the future," Sharifuddin said.
Research on health risks remains split and like Malaysia, few countries have introduced national legislation to regulate the sector.
The devices function by heating flavoured nicotine liquid -- or e-juice -- into a vapour that is inhaled, much like traditional cigarettes but without the smoke.
Some experts warn vaping can produce cancer-causing formaldehyde and one US study said vaping is up to 15 times more harmful than traditional tobacco smoking. The World Health Organization has called on governments to ban the sale of e-cigarettes to minors.
But other research suggests vaping is safer than smoking cigarettes and manufacturers tout them as harmless aids to quit tobacco.
Enthusiasts in Malaysia say banning the habit doesn`t make economic sense.
"Vaping communities are fighting for their rights because the vape scene actually brings profits to the country," said Muhammad Imman, marketing manager of the colourfully named Fcuking Flava vape shop, one of thousands that have popped up across the country.
Marketers cater to local tastes, selling e-juice flavoured with snake fruit, lychee and even durian, the notoriously pungent Southeast Asian fruit.
The juices are marketed like single-malt whiskies or perfumes, as seen at a recent vaping convention in Kuala Lumpur, their creators extolling organic and other premium ingredients.
Aficionados gather daily in Malaysia`s vape shops, sometimes for "cloud chasing" competitions to see who can produce the biggest vapour puffs and to show off vape prowess by blowing rings into the foggy air.
Some agree there is a greater need for quality control to keep dodgy DIY e-juice from entering the market and to ensure e-cigarette devices aren`t used for smoking drugs like marijuana.
A growing number of amateur merchants have emerged across the country, where about a million people smoke e-cigarettes, a five-fold surge since last year, according to the Malaysia E-Vaporizers and Tobacco Alternative Association (MEVTA) activist group.
Making e-juice is a simple process that involves mixing readily available ingredients -- water, flavouring, nicotine and other easy-to-access chemical compounds.
On a Kuala Lumpur street recently, a vendor set up a table arrayed with a range of flavours, from guava to lychee on sale for about 30 ringgit ($7).
"Mine are the best," he boasted to passing office workers.
But some bottles looked old and reused, and he was tight-lipped on the e-juice`s origin.
Other more mainstream Malaysian manufacturers have struck deals to distribute their goods elsewhere in Asia and as far afield as Europe, as Malaysian flavours become popular overseas.
The habit doesn`t appear to be losing steam at home, especially among former smokers.
"I actually have reduced the level of nicotine when I vape," said officer worker Nicolas Chan, speaking between puffs on his lunch break.
"I feel better and have more energy after quitting cigarettes and starting to vape."