You would have to be living in a cave to have missed the CBD (cannabidiol) craze that is sweeping across America: New products are cramming store shelves as the market explodes for what many Americans believe to be a miracle cure-all.
Everything from oils to gummies to pills, creams and ointments are now for sale at supermarkets and specialty chains. You can even get massages infused with CBD, or cosmetics laced with the drug.
A 'flood' of products
All of these products contain cannabidiol but not THC, the ingredient in pot that provides a "high". But what do scientists really know about the health benefits and risks of CBD?
Precious little, experts say, and consumers should take care that they aren't wasting their money.
"You have a flood of CBD products that are coming from hemp that are going out onto the market, and you've got all sorts of claims being made about those from people are trying to sell them," said Timothy Welty, chair of the department of clinical sciences at Drake University's College of Pharmacy and Health Sciences, in Des Moines, Iowa.
The flood of CBD products has become so overwhelming that the US Food and Drug Administration recently stepped into the fray.
The agency has whipped out a flurry of warning letters to companies marketing CBD products, telling them to stop making unfounded health claims for the substance.
Companies have falsely claimed that CBD can stop cancer cells, slow the progression of Alzheimer's disease, ease nerve pain and fibromyalgia, and curb withdrawal symptoms for people undergoing substance abuse treatment, the FDA letters state.
What started the craze?
The agency will hold a public hearing regarding CBD products and their safety, and it has formed a working group to consider new laws and regulations to govern this Wild West market.
CBD products have swamped the market not because of any new medical evidence, but because of a change in federal law, Welty noted.
Late last year, Congress passed a farm bill that lifted a decades-old ban on growing hemp. As long as the plant contains less than 0.3% THC, hemp can be grown legally anywhere in the United States by licensed farmers.
The bill specifically said the US Drug Enforcement Agency cannot regulate hemp products like CBD, Welty said. So, it's now up to the FDA to regulate the CBD craze.
The body contains a system of receptors that respond to the compounds in marijuana, including both THC and CBD, noted Dr David Copenhaver, director of cancer pain management and supportive care for the University of California, Davis Health Center.
Because of this, researchers have been highly interested in the potential benefits of CBD regarding a number of different health problems.
Potential to treat anxiety disorder
To date, there's only one use for CBD that has significant scientific evidence behind it – curbing the symptoms of rare forms of epilepsy.
The FDA last year approved the drug Epidiolex to treat two forms of childhood epilepsy. The medical evidence has shown that the highly purified CBD in Epidiolex can ease seizures.
For the rest of CBD's potential uses, there is simply too little evidence to make a firm conclusion.
The next potential medical use for CBD could be for the symptoms of anxiety disorder, said Welty and Yasmin Hurd, chair of translational neuroscience and director of the Addiction Institute at Mount Sinai.
Clinical trials suggest that CBD could help treat anxiety, but Welty feels there needs to be more study. Hurd is slightly more convinced, but agrees more study is needed.
"There is published evidence that CBD does decrease anxiety," Hurd said. "That's another indication where I can say I can believe the data; however, we still don't know the dosing regimen that would be effective for anxiety. Those are studies that are ongoing."
Other uses – as an anti-inflammatory, an aid for substance withdrawal, a sleep aid, a pain reliever – haven't been conclusively proven.
In some cases, the evidence runs counter to what people might suspect.
There's not much reason to believe CBD would be an effective means of pain relief, said Dr Ajay Wasan, vice chair for pain medicine at the University of Pittsburgh Medical Center.
"If you think of it as a medicine, it would be a weak analgesic," Wasan said. "It's really the THC component of medical marijuana which is the compound that gives you pain relief."
Possibility of harm
CBD might actually make the eye disease glaucoma worse, according to a study published last December in the journal Investigative Ophthalmology & Visual Science.
Researchers found that CBD eye drops increased ocular pressure in mice, even as THC appeared to reduce pressure – which might explain why medical marijuana has had mixed results when it comes to studies on glaucoma treatment.
"I've been surprised how much CBD has taken off and exploded with very little data," Wasan said. "Most of the other herbal supplements, there are at least some studies on it before it becomes really popular. But for this, I haven't seen anything."
The bottom line, researchers said, is that people who want to try CBD for one reason or another should talk with their doctor first. Welty noted that Epidiolex can be put to "off-label" use for other conditions if a doctor feels it might work.
Besides that, consumers might consider buying CBD products from a state-run programme. Some states like Iowa have established such programmes to make CBD available medicinally, Welty said.
"Those products are more reliable, because they have a system to monitor the purity of content," Welty said. "You're a little more sure that you're getting what you're paying for."
Many unregulated products
Welty is much less sure of the "artisanal products" containing CBD that are available in stores and dispensaries, and for good reason – studies have shown that most of these products fail tests for content and purity.
A 2017 study concluded that nearly seven of 10 CBD products didn't contain the amount of cannabidiol promised on the label, according to findings published in the Journal of the American Medical Association.
Nearly 43% of the products contained too little CBD, while about 26% contained too much. Worse, about one in five CBD products contained the intoxicating pot chemical THC.
"The CBD products that come through that route, there's essentially no control, and you as a consumer have no way to know what you're getting," Welty said.
Copenhaver believes other legitimate uses for CBD could be found, but it will require a more extensive knowledge of the way the human body responds to marijuana's different compounds.
People might do best to wait until the dust settles regarding the medical evidence, rather than being caught up in the CBD craze, Hurd said.
"It's like we do this every 30 years or so," Hurd said. "We romanticise something, that this is going to be the cure-all for every disorder. We've never found that."
Image credit: iStock