Tai Ayala's dependency on prescription medications to control both anxiety and irritable bowel syndrome still left her anxious about holding on to a full-time job.

The 25-year-old Royal Oak resident was never sure that she would be able to make it to work without having an accident or a flare-up. So two years ago, she turned to a product that is becoming more and more ubiquitous in the marketplace — CBD or cannabidiol, the non-psychoactive element of the cannabis plant — and has weaned herself off the prescription meds.

"I have a medical marijuana card, but I was more interested in the whole CBD aspect of it because I wanted something that was going to help with my IBS, so I could do my job without feeling impaired mentally," said Ayala, who is a budtender at the Greenhouse medical marijuana dispensary in Walled Lake. "When I made that switch to CBD, it definitely improved my way of life."

While the research on the benefits of CBD is scarce, there is a plethora of anecdotal evidence of how it has helped treat everything from chronic pain from such conditions as arthritis, multiple sclerosis and cancer; anxiety, depression and insomnia; addiction to tobacco and opioids; muscle spasticity and other health problems associated with multiple sclerosis and Parkinson’s disease; acne, and seizures among those with epilepsy.

More:CBD-infused products arriving at Kroger stores this week

More:Michigan's new rules could make CBD products easier to find

As a result, the market is flooded with products for humans and pets. BDS Analytics, a Colorado-based company that tracks the cannabis industry, has projected that CBD sales will reach $20 billion by 2024.

“We’re witnessing CBD maturing from a cannabis sub-category into a full-blown industry of its own,” attracting 15% of adults in the United States, said Roy Bingham, co-founder and CEO of BDS Analytics.

Other than one prescription drug, Epidiolex, which is used to treat severe forms of epilepsy, the U.S. Food & Drug Administration has not approved CBD products and does not test them.

That means there’s no federal oversight to ensure that what you think you’re buying is what you are actually getting, said Dr. Peter Grinspoon, a Harvard Medical School professor and a primary care doctor at Massachusetts General Hospital who wrote a memoir called “Free Refills: A Doctor Confronts His Addiction,” about his recovery from opioid addiction.

The American Medical Association says more well-controlled studies are needed on the use of marijuana and CBD for patients who have serious conditions before more states legalize pot for adult recreational use. The organization also has called on the federal government to review the status of marijuana as an illegal controlled substance "so clinical research and development of cannabinoid-derived medicines can take place."

It also supports research that would help to determine the consequences of long-term cannabis use, especially among young people, pregnant women, and women who are breastfeeding.

Despite the warnings from the AMA, 11 states have legalized marijuana for adult recreational use and 33 states have approved medical marijuana, and CBD is all the craze. You can buy it online in lotions, creams, oil, patches and tinctures. It’s at your local health food stores, gas stations, video stores and even at the Kroger around the corner. Products containing CBD are practically everywhere.

What is CBD and how much is it regulated?

An extract derived from the flowers and buds of hemp, CBD is legal in the United States as long as it contains less than 0.3% THC, the psychoactive component of marijuana, which gets people high.

Hemp and marijuana are both cannabis plants, but hemp has much lower concentrations of tetrahydrocannabinol, or THC. Since 1970, all cannabis has been categorized as a controlled substance and, as such, considered illegal by the federal government. But the 2018 farm bill legalized hemp and provides for regulating the growth of the plant.

But even though it’s legal and there’s easy access to CBD products, it’s very much a matter of buyer beware, Grinspoon said

“You could get pesticides or heavy metals in the product,” said Grinspoon, an expert on medical marijuana who serves on the board of directors for the Doctors for Cannabis Regulation. “And some of the CBD samples that have been tested even had (higher than legally allowed levels of) THC in them."

“I’m not against THC. I am a medical cannabis provider. But the last thing you want is THC when you’re not expecting THC," he added. "You could be driving home (after using such a product) and that is profoundly dangerous. The fact that it’s unregulated and you don’t know what dose you’re getting or if you’re getting something else on top of CBD is dangerous.”

Michigan’s Department of Licensing and Regulatory Affairs does not regulate CBD products with less than 0.3% THC. Those hemp-based products are handled by the Michigan Department of Agriculture and Rural Development, which issues licenses for the hemp growers and processors.

After starting a pilot program earlier this year, MDARD has registered and licensed 541 hemp growers in the state who are expected to plant more than 32,000 acres. Additionally, 389 processors who transform the hemp into other products have also been licensed.

The growers will have to have their hemp plants tested, either at the MDARD labs or labs licensed by the state to test medical marijuana, to make sure the plants contain no more than 0.3% THC. Once the hemp is transformed into CBD products, it becomes the U.S. Food and Drug Administration's responsibility.

But the FDA hasn't been testing CBD products, either. At Greenhouse and other retail outlets where CBD is sold, the products don't have stamps of approval, like what you might see on vitamins. However, Angie Roullier, the dispensary's team leader, said all the products it sells have been tested and those results are available to customers, who can buy the products without a medical marijuana card in a room next to the dispensary.

Any product with more than 0.3% THC is regulated in Michigan as marijuana, which now is legal for medicinal use and will be commercially available for sale by late this year or early in the new year for recreational use to anyone 21 and older. Those products are regulated by the state's Marijuana Regulatory Agency.

What are the concerns about CBD products?

Grinspoon said the concerns about the CBD products on store shelves include no one checking that the products and dosages listed on the CBD labels are accurate.

“Assuming you are getting the right dose of CBD and it’s just CBD," Grinspoon said, the two things consumers need to be concerned about are:

It could raise the levels of certain other medications in your blood in exactly the same way that grapefruit juice does. … So if you’re on blood thinners, you’re certainly going to want to tell your doctor that you’re on CBD so he or she can check the level of your blood thinners more carefully.

Your doctor might want to keep an eye on your liver enzymes because some of the trials of CBD elevated the level of liver enzymes.

“But overall, it’s a lot safer than anything else you’d be using if you’re using it instead of opioids for pain or Ambien to help you sleep or instead of benzodiazepine for anxiety," Grinspoon said. "It’s a lot safer than those. But there is no free lunch in medicine, so you have to keep an eye on certain things.”

Does CBD really work?

Beyond those risks is the question of whether CBD works at all for conditions other than epilepsy, and what dosage is ideal for the best effects.

At the University of Michigan, Kevin Boehnke, Ph.D., research investigator in the department of anesthesiology and the Chronic Pain and Fatigue Research Center, and Daniel Clauw, M.D., a professor of anesthesiology, medicine, and psychiatry, took a look earlier this year at why people were using CBD and found that most people cited relief from chronic pain as their top reason.

“CBD is incredibly accessible, as it is available online from a variety of vendors," Boehnke said. "However, the quality control for safety and potency is widely variable.”

They found that there's not enough fact-based evidence available to suggest that CBD should be recommended as a first choice treatment option for chronic pain.

"There's a lot of snake oil out there. We see it every day," Rouiller said. "Somebody will bring me in a bottle of what is supposed to be 1,000 milligrams of CBD tincture, and they're saying it's not working. They're frustrated that they spent all this money on a product that isn't working. And we'll turn the bottle around and look at the fine print on the label. And it'll say 5 milligrams of CBD. So at that point, it's glorified coconut oil."

Grinspoon said even though people swear that CBD products are helping, “in general the enthusiasm has outpaced the hard-core science on the efficacy."

While many people attest that CBD brings them relief from pain and other symptoms, few medical research studies have been done on marijuana and marijuana derivatives like CBD:

A study published in the European Journal of Pain in 2016 showed that CBD reduces arthritis pain in rats without side effects, but there haven’t been comparable human studies.

There have been small studies on the benefits of CBD in treating Parkinson’s, social anxiety, schizophrenia and post-traumatic stress disorder, but a 2017 review of those studies by the National Institutes of Health suggested that while there may have been some benefits in using CBD to treat those ailments, the small sample size of the studies (less than 100 patients) couldn’t translate into blanket conclusions that CBD was beneficial.

“I’ve had patients have what seems like a pretty dramatic effect beneficially, and I’ve had other people say, ‘Why did I just waste $60 on this? It didn’t do anything,’ ” Grinspoon said. “It’s very variable. It’s complicated by the fact that it’s not that regulated, so you have to be a savvy shopper to even be sure that you get the right amount of CBD that you’re ordering.”

For the last few decades, research has been stymied by a national anti-drug sentiment, and federal policy that still considers marijuana an illegal substance.

“It used to be that if you wanted to study whether cannabis or anything cannabis-related is harmful, you could get a huge grant,” he said. “But if you wanted to study something beneficial, like does CBD help with pain, you wouldn’t get funded by the U.S. government.

That has started to change as research institutes begin more and more studies on the health benefits of marijuana. The International Phytomedicines and Medical Cannabis Institute at Harvard University was launched in May to study the effects of plant-based medicines, including cannabis, and making those medicines available globally.

While there has been a good deal of animal research with cannabis and CBD, Grinspoon noted that animal studies don’t always translate perfectly to humans.

“For certain things, we have human data for CBD,” he said. “For childhood epilepsy, there was enough human data for the FDA to approve the drug Epidiolex for childhood epilepsy."

What to look for before you buy a CBD product

For anyone who decides to try it, Grinspoon’s best advice is to choose only CBD products that are independently lab tested.

“Look for a certificate of assurance that they have had independent testing,” Grinspoon said. “Don’t just take their word for it. You know, if you go into a gas station, you’re not necessarily going to get good CBD. But if you go to one of these online places that has a lot of good reviews and has independent lab testing or a COA, certificate of assurance, that they’ve had independent testing, then you’re much more likely to get actual CBD.”

And Rouiller suggested that consumers also look at where the product is manufactured and choose American-made products because the soil in other countries where the hemp is grown could be suspect.

"There's a lot of products that are coming in from China and other places where they couldn't care less about the dirt that they're growing in," she said. "That's when you get things like heavy metals."

Contact Kathleen Gray: 313-223-4430, kgray99@freepress.com or on Twitter @michpoligal.