Cannabidiol (CBD), a derivative of cannabis, was banned in Hong Kong on Wednesday (Feb 1), forcing fledgling businesses to close.

Unlike its more famous cousin, tetrahydrocannabinol (THC), the psychoactive ingredient in marijuana that has long been illegal in Hong Kong, CBD - derived from the cannabis plant - is said to relieve stress and inflammation without getting users high, unlike THC.

In the city, CBD was once legal, and young people frequented CBD-infused cafes and shops.

With the prohibition, which took effect Wednesday but was announced by the government last year, all that has changed.

Many CBD-related businesses have closed, while others struggled to remodel. Consumers dumped what they saw as a cure for their ailments into special collection boxes.

In Hong Kong and mainland China, where CBD was banned in 2022, the new rule reflects a zero-tolerance policy toward dangerous drugs.

There are several categories of "dangerous drugs" in the city, including heroin and cocaine.

Hong Kong's government explained the policy change by citing the difficulty of isolating pure CBD from cannabis, the possibility of contamination with THC in the production process, and the ease with which CBD can be converted to THC.

The customs authorities promised last week to educate residents about the fact that CBD is illegal in Hong Kong, despite it being legal elsewhere.

As of Wednesday, possession of CBD can result in up to seven years in jail and a fine of 128,000 Hong Kong dollars. It is possible to face life in prison and a fine of 5 million Hong Kong dollars (US$638,000) if convicted of importing, exporting, or producing the substance.

The ban has been interpreted by some users as evidence that the international financial hub is regressing.

"It's just looking less like an international city," said Jennifer Lo, who started selling CBD-infused cheesecakes, cookies, and drinks in 2021.

Even before the ban went into effect, her business largely dried up.

She explained that rumours of the ban affected her business. "Some platforms took me offline without telling me. And then it became harder to get market space."

The ban forced Lo to dump all her remaining stock, including dozens of cookies, and rebrand her business.

The city's first CBD cafe, which opened in 2020, shut down as well.

She will have to find an alternative treatment for her eczema, said Karena Tsoi, who used CBD skincare products for two years.

"This is troublesome," she said. "Government shouldn't be regulating in this way."

Except for Thailand, which legalized marijuana cultivation and possession last year, most Asian nations have strict drug laws with harsh penalties.

CBD continues to be debated elsewhere.

Earlier this month, the Food and Drug Administration said there was not enough evidence to confirm the safety of CBD in food or as a dietary supplement. It called on Congress to create new rules for the growing market.

As marijuana-derived products have become increasingly popular in lotions, tinctures, and foods, their legal status has been murky in the US, where several states have legalised or decriminalized substances that remain illegal federally.