Many people know Dana Larsen as a dispensary owner and one of the organizers of 4/20 Vancouver, but now the long-time cannabis activist is launching a new service aimed at users of harder drugs.

Larsen has bought a $40,000 spectrometer that can analyze a few milligrams of a substance and fairly accurately determine its chemical make-up.

"We'll be able to analyze it and let them know what's in their substances and hopefully they can make more informed decisions about their drug use," Larsen said.

Larsen plans to set up a storefront where people can walk in off the street and have their drugs tested while they wait, but he also wants people from other parts of the country to send him samples through Canada Post.

"Technically what I'm offering here is illegal. It's considered trafficking if I take drugs from somebody else for these testing purposes," said Larsen. "But I'm not really too worried about that. We're in the middle of a devastating overdose crisis."

He says he will offer safe packaging guidelines to users of the service and doesn't believe the amounts in question, a few milligrams, will pose a health risk to postal workers.

"And of course, the reality is that there are lots of drugs going through the Canadian mail system right now anyways," Larsen said.

In his downtown office Wednesday, Larsen offered CTV News a demonstration of the machine and testing procedure, using a sample from a small plastic bag of white powder.

"Found on the ground, so no idea what it is," said Jared Evans, as he placed a few milligrams of the substance on the spectrometer.

The sample turned out to be about 50 per cent cocaine, and about 50 percent something else entirely.

"Essentially, the cocaine has a lot of benzocaine in it. I would tell this individual that it's probably closer to a half-half mix," said Evans. "I've found that the cocaine samples tend to have the most fluctuation in their consistency."

Benzocaine is a numbing agent commonly found in over-the-counter oral gels.

The test results don't surprise Kevin Hollett with the BC Centre on Substance Use.

"Our initial evaluation found that nearly two-thirds of all substances contained something else entirely than the person thought they were getting," said Hollett.

Larsen says he plans to share the test results with the people who send the samples in, on his website, and with the BC Centre on Substance Use which will include them in its monthly reports on the drug supply.

Larsen also hopes drug dealers will also send him samples of their products.

"A lot of dealers don't really know what they're selling," he said. "They buy some pills or powder from one source and they re-sell it to another one. So they will also be able to find out more about what they're selling and help their customers make better decisions."