In an article posted previously, people were saying that it's strange how G-Dragon's marijuana test came out positive when he's reported to have only taken a couple of puffs. (Implying that he's a regular user)

On MBC's Good Day show, they interviewed an officer from the National Forensic Service and asked some questions regarding hair testing for marijuana. Here's how the interview went:

Q: Is it possible to get a positive result from smoking a couple of puffs of marijuana?
Officer: It's difficult to say because only a trace amount of marijuana remains on the hair. It's hard to say if it will show after smoking once or not.

Q: Does this mean that a trace (amount) can be found even after only smoking just once?
Officer: It's possible depending on the situation. There is no specific period on how long the components remain on the hair. For hair that is 3cm long, the trace can remain up to 3 months as long as it's not cut off.

In the article posted previously, the former director of the Korean Police Narcotics Bureau said that it's rare to get a positive hair test result after smoking only a couple of puffs. According to this most recent interview, it is possible.

Source: DCGD (Thanks @withSsung)
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