Inside the Groundswell Cannabis Boutique in Denver, it looks like any other high-end retail store. A display case made of dark wood runs down the middle of the room.

“Clean, simple experience because we have a lot to tell,” said Don Novak, the store’s owner.

Under the display case’s nicely lit glass are ceramic dishes, each with a dried marijuana flower next to a card with the name of the variety—Purple Cotton, Maui Strawberry, Cherry Pie. Built into the walls are display cases showing off the various marijuana products for sale.

 “You have your concentrates, and then you have edibles, tinctures, drinks, patches, topicals and the other infused products that we carry,” Novak said.

State regulators were a bit taken aback by the range of products for sale.

“Spaghetti sauces, energy drinks, candy bars, gummy bears, all with these varying degrees of potency,” said Larry Wolk, the head of Colorado’s Department of Public Health and Environment. Wolk said they realized they needed to do something so it would be clear to people what they were getting, and how much of it.

“So as a state and regulatory agencies, we quickly recognized that and moved in to standardize packaging, standardize THC [tetrahydrocannabinol] potency amounts to a standardized, single serving,” he said. 

So now if you’re eating a square of a chocolate bar that’s considered a single serving, you know you’re getting 10 mg of THC. Colorado launched an educational campaign that tells people to take it easy on the edibles—start with a small amount to see what happens. The state also required child-safe packaging and banned gummy candy in the shape of bears or little people or anything that might appeal to kids. Wolk said his job got a little tricky when pot became legal.

“You know, as a physician, a public health guy, a pediatrician, it’s a lifetime of learning about the ills of marijuana, so it took a little bit of adjusting on my part as a regulator to stay objective, to stay evidence based,” he said.

But he said when he objectively looked at what had happened in the state “it was a bit surprising to see that we really haven’t seen an increase in adult use, nor youth use, as a result of legalization."

Wolk said they think the adults using marijuana now were already using before it was legal. As for youth, in a 2015 state survey, 21 percent of middle and high school students said they’d used pot in the last 30 days, which is actually slightly below the national average.

But some parents are worried, since research shows marijuana is bad for the developing brain. Diane Carlson is a founder of an anti-legalization advocacy group called Smart Colorado.

“Colorado kids are not viewing marijuana today as risky, and if you really look at that study, youth use varies dramatically from different areas within the state," Carlson said. "And two of the real epicenters of commercialization where there’ve been the most stores, youth use is up significantly.”

In Denver, where there are about 250 dispensaries, the state’s study showed more than 30 percent of middle and high schoolers reported using pot in the last month. And while some might be getting hands on their older brothers’ or parents’ stash, there’s also a black market they can buy from.

“We’re spending more time than ever on marijuana enforcement in Colorado,” said Jim Gerhardt, a police sergeant and the vice president of the Colorado Drug Investigators Association. Gerhardt said in addition to sales to young people and adults who want cheaper, untaxed pot, some of it is getting sent to states where it’s illegal, or even sold out of the country. He said a lot of that pot is coming from people’s homes—which complicates things for law enforcement.

“It used to be if you found a marijuana growing operation in a person’s home, it was illegal. It was on its face illegal," he said. "You could deal with that very quickly and efficiently. It’s legal now. It is legal to grow marijuana in a person’s home. That’s what fuels it. And in Question 4, you have the exact same ability to grow marijuana in your home that you have in Colorado.”

Question 4, of course, is the referendum we’re voting on here in Massachusetts next week.

Inside a nondescript warehouse in an industrial neighborhood of Denver is a giant room, full of thousands of young marijuana plants.

“So this is the nursery, this is kind of where it all starts,” said Duncan Cameron, chief production officer for a company called Good Chemistry.

Most of the state’s recreational pot comes from places like this. It’s warm and humid, and high power fluorescent lights beam down. 

“We’re not trying to mimic nature, we’re trying to beat nature," he said. "These lights are on for 24 hours a day.”

In each plant is a small blue or yellow tag. “So these are RFID tags that the state requires us to purchase,” Cameron explained.

Those tags allow the state to track each and every plant grown by a commercial grower, to make sure they don’t get into the wrong hands.

It’s one of the things supporters point to as a major benefit of legalization.  If people are smoking anyway, they say, isn’t it better that the state can monitor what’s grown, what pesticides are used, how it’s marketed and sold, and tax it to pay for that regulation?

Wolk pointed out the long-term data on the impact of legalization isn’t in yet. So if Massachusetts voters choose next week to legalize, he has some advice for regulators here: Start out by being restrictive.

“Once the horse is out of the barn it’s a little more difficult to pull back,” he said.

It’s essentially the same advice he has for people trying marijuana edibles for the first time. Start small and see what the effect is.