The cannabis extract is being hailed as a miracle drug. Is there any evidence that it works? Here's everything you need to know:

What is it?

Cannabidiol, or CBD, is a compound in the Cannabis sativa plant that doesn't get you high. (THC is the psychoactive component in marijuana that makes people euphoric.) CBD has exploded in popularity over the past year, because it's been purported to do just about everything: relieve pain; reduce anxiety and stress; and treat inflammation, insomnia, headaches, hangovers, nausea, skin disorders, joint pain, muscle spasms, and period cramps. When ingested, CBD affects cannabinoid receptors throughout the body, which have a regulatory function. CBD products were once limited to medical marijuana shops, but now those made from hemp — marijuana's low-THC cousin — are available online and in health-food stores, supermarkets, and even gas stations; next year, nationwide sales are expected to soar to $22 billion by 2022. Following endorsements from such celebrities as Jennifer Aniston, Joe Rogan, and wellness tycoon Gwyneth Paltrow, CBD was destigmatized seemingly overnight. "CBD is the chemical equivalent of Bitcoin in 2016," New York advertising executive Jason DeLand said. "It's hot, everywhere, and yet almost nobody understands it."

How is it ingested?

Some puff it from a vaporizer, but it's mainly produced as an oil concentrate, allowing it to be mixed in juice or other liquids and consumed by drinking. It's also being blended into bath bombs, lotions, and ointments as a topical treatment, and added to nearly every food imaginable, from ice cream and smoothies to gumdrops and salad dressing. A ritzy New York hotel offers an all-CBD room-service menu (meatballs and tater tots are best-sellers), and for a few extra bucks, cafés across the country will add a shot of it to your latte. Last summer, stoner icon Willie Nelson began selling "Willie's Remedy," a CBD-infused coffee, and major companies such as Coca-Cola are rumored to be considering bringing CBD beverages to the mass market.

So it's legal?

It's actually in a gray area. The Food and Drug Administration still classifies CBD made from the marijuana plant as a Schedule 1 substance, along with drugs like heroin and LSD. Just one CBD-based ­pharmaceutical — Epidiolex, which treats rare forms of pediatric ­epilepsy — is FDA approved, and it's illegal for CBD products to advertise medical benefits. Nonetheless, many small shops and online retailers sell hemp-derived CBD in states where marijuana is banned. The legality of CBD got a big boost in December, when President Trump signed the 2018 Farm Bill, which legalized commercialized hemp production. (It had been outlawed in 1937.) Hemp is a cannabis plant that contains less than 0.3 percent of the psychoactive compound THC and has been used for millennia in food and to make products like rope, paper, and textiles. The new law did not explicitly legalize hemp-derived CBD, but opened the door for the burgeoning market to become federally regulated.

How will that help?

Without regulation, CBD products are marketed and labeled about as reliably as snake oil. A 2017 University of Pennsylvania study examined 84 CBD products and found that nearly 70 percent were ­mislabeled — 40 percent had significantly more CBD than advertised, while about a quarter of them had significantly less. Dosage recommendations wildly vary. Alarmingly, about 20 percent of the products contained a significant amount of THC, which would show up on a drug test. "It really is the Wild West," said Marcel Bonn-Miller, the professor who led that study. "Joe Bob who starts up a CBD company could say whatever the hell he wants on a label and sell it to people."

Is CBD backed by science?

Most findings are preliminary at best, since research on CBD itself began only a few years ago. Studies on both animals and humans so far have found some evidence it might alleviate psychotic disorders, lessen anxiety, relieve mild or moderate pain, and reduce insomnia; as for cosmetic claims, one study found CBD reduced visible signs of aging in mice. Scientists say, however, that high-quality, double-blind clinical trials on humans need to be conducted to verify CBD's purported benefits. There's also uncertainty about proper dosage levels, CBD's side effects, and how CBD products interact with other drugs.

Where do experts stand?

Research may be sparse, but unlike, say, crystals and healing bracelets, CBD clearly does have biological effects. "I think there is a legitimate medicine here," says CNN chief medical correspondent Dr. Sanjay Gupta, a neurosurgeon. "We're talking about something that could really help people." That said, there is plenty of skepticism that CBD is a magical elixir. "There's an enormous placebo effect," said Dr. Margaret Haney, director of Columbia University's Marijuana Research Laboratory. "If you go in with this expectation, with all of society saying this will cure whatever ails you, it often will." Some call CBD "the new avocado toast" — a fad for ­wellness obsessives — but DeLand, the ad exec, believes that CBD's benefits will be confirmed or debunked before too long. "The future of this industry," he said, "is going to be based on fact, not fiction."

The GOP's embrace of hemp

The Republican Party's long-standing hostility toward cannabis was captured by former Attorney General Jeff Sessions, who famously said, "Good people don't smoke marijuana." Yet the GOP, which has opposed even medical marijuana, lined up behind legalizing commercial hemp and hemp-based CBD in the latest farm bill, with Senate Majority Leader Mitch McCon­nell (R-Ky.) leading the charge. McCon­nell's state of Ken­tucky used to have a robust hemp sector that now seeks to profit from CBD boom times: The global hemp market is projected to jump to $10.6 billion by 2025, and hemp grown for CBD oil can take in upward of $35,000 per acre — corn, by contrast, takes in less than $600 per acre. In pilot programs, Kentucky produced $16 million worth of hemp in 2017 and attracted $25 million in investments. In Decem­ber, McCon­­nell said legal hemp production would usher in a new era. "At a time when farm income is down and growers are struggling, industrial hemp is a bright spot of agriculture's future," he said. "It's time to show the world what Ken­tucky farmers can do with hemp."